Eclipse Engineering, Inc.

O-Ring Energized Seals vs. Spring Energized Seals: Choosing the Right PTFE Seal Energizer

Tue, 17 Mar 2026 02:16:12 GMT

While PTFE has many great properties, it is well known that elasticity is not one of them. In high-performance sealing applications, a secondary energizing element is required in almost all cases. Most PTFE seals are energized in one of two ways: with a metallic spring or with an elastomeric O-Ring.

Both methods ultimately accomplish the same goal — keeping the PTFE in contact with the sealing surface at all times — but each method has distinct characteristics. We’ll see that some applications will clearly favor one method over the other, but in some cases, either design could be used.

Below, we’ll talk about the advantages and disadvantages of both O-Rings and springs as energizers and why you might choose one over the other.

Operating Temperature Range for PTFE Seals

One of the most decisive factors in determining which energizing method is better for an application is the operating temperature range. Spring energized seals are limited only by the temperature capability of the PTFE itself, which is typically cryogenic (-450°F [-270°C] to +500°F [260°C]).

While some O-Ring materials can survive at significantly high temperatures, the reduced properties can often rule them out. At the other end of the spectrum, most O-Rings become hard and rigid at temperatures below -40°F [-40°C], effectively rendering them unusable. If the application is operating in extreme temperature conditions, the choice is often clearly spring energized seals.

Chemical Resistance and Media Compatibility

Another factor definitively favoring spring energized PTFE seals is if the application is operating in corrosive media. While PTFE is chemically inert to virtually everything, the chemical compatibility of O-Rings in certain media is something to carefully consider.

Strong acids and caustic solutions may rule out the use of O-Rings altogether. Other media, such as thick epoxies or resins, can encapsulate O-Rings, interfering with their functionality. Spring-loaded seals can often operate more successfully in these types of aggressive media.

Friction Control and Loading Characteristics

O-Rings were primarily designed to be sealing elements themselves; the fact that they can act as a spring is a secondary function. In fact, O-Rings don’t really compress the way metallic springs do — their shape is displaced rather than compressed. This is why O-Ring occupancy in a groove is calculated and designed around. If there is no room for the O-Ring to displace, it will fail to act as a spring.

The load vs. deflection curve of an O-Ring is very short and steep. The unit load is quite high compared to a Cantilever V-Spring or Canted Coil spring . They are effectively a much cruder energizer compared to their metallic counterparts.

In friction-sensitive applications, it’s clear that an energizer with high unit load and a short deflection range would not be the ideal choice. This is where the Canted Coil spring has a distinct advantage. Canted Coil has the unique property of having a near-constant load over a relatively broad deflection range. This means a seal can be designed to have predictable and controlled friction characteristics despite changing conditions and seal wear.

Canted Coil spring seals are typically the best choice for any application where reducing torque or friction is the objective. This is especially true in rotary seal applications where excessive loading will increase localized heating, contributing to expedited seal wear. O-Ring energized seals are usually only considered in very slow rotary applications.

Cantilever V-Spring can be advantageous in reciprocating applications requiring a heavy scraping effect. V-Spring can focus the loading force on the leading point of the sealing lip. Furthermore, multiple V-Springs can be stacked within a seal jacket corresponding to multiple sealing points on the lip. Eclipse has had great success with this configuration in viscous media applications. Such point loading could not be accomplished with an O-Ring.

Shelf-Life and Seal Longevity

While some applications require extended service intervals, others can take this to the extreme. Eclipse has provided seals to multiple dam and spillway gate projects where the life of the seal needs to be 50+ years. Some O-Ring compounds can have “unlimited” shelf-life, but most are not intended to be in service for so long.

Regardless of the compound, O-Rings are all subject to compression set. This is when the O-Ring becomes flattened over time and no longer returns to its original shape, thus ceasing to provide energy for sealing.

Spring Energized PTFE seals have indefinite shelf and service life. They are also impervious to many forms of environmental degradation, including UV exposure. If the seal needs to last for decades, a spring-energized seal is the superior choice.

So far, it might seem like Spring Energized Seals have the upper hand. But despite being the more sophisticated, advanced engineered product, they may not always be the optimal choice.

Sealing Performance and Surface Finish

O-Ring Energized seals can have a leg up on spring energized seals in terms of sealing performance because they have an O-Ring sealing on the static side of the gland rather than another PTFE interface. O-Rings will always have superior sealing ability compared to PTFE, especially on poor hardware surface finishes.

Even under the best conditions, PTFE will never achieve full “zero leak” capability, while an O-Ring most certainly can. Obviously, having only one PTFE interface instead of two will have a significant impact on sealability. The geometry of O-Ring Energized Seal rings can also be beneficial for sealing in some media. Compared to spring seals, the “contact patch” of a seal ring is typically much broader, creating a physically longer barrier and a longer leak path.

Gland Design and Installation

One clear advantage O-Ring Energized Seals typically have over spring seals is the simplicity of their groove design. Except at extremely small diameters, O-Ring Energized seals can be installed in solid glands. This is merely a rectangular groove cut in the hardware—from a manufacturability standpoint, this is as straightforward as it gets.

Piston configurations: Seal rings can be stretched into the groove on top of the O-Ring.
Rod configurations: Seal rings can be formed into a “kidney bean” shape to be installed in an ID groove.

In the vast majority of cases, it is impossible to install a Spring Energized Seal in a solid gland without damaging the spring. Therefore, solid glands are generally not recommended for spring seals.

Spring seals will require the gland to be a split or stepped configuration. Split glands require multiple hardware components and a larger design envelope, adding cost and complexity to the system. Furthermore, because spring seals have a PTFE interface on the static groove side, secondary polishing in the gland is often required. An O-Ring energized seal will operate fine on an “as machined” surface in the groove.

Cost Considerations for PTFE Seals

An O-Ring Energized Seal ring is highly economical for large-quantity production. In high-volume cases, raw PTFE billets can be near-net molded to minimize material waste and maximize machine run-rates.

Spring Energized Seals, in contrast, are much more complex to machine. The face groove to house the spring requires specialized tooling. It’s also not surprising that the spring itself is a more costly component than an off-the-shelf O-Ring. With a more expensive energizing element and supplementary labor steps (cutting, welding, and installing the spring), spring-energized seals are naturally more costly.

Wear Life and Material Thickness

With certain designs, O-Ring Energized Seal rings can have an advantage in terms of wear life. The simple design allows for a relatively thick radial wall. The more physical material there is, the longer the potential wear life.

The “U” shaped geometry of spring-energized seals means the sealing lip needs to be hinged. If the lip is too thick, the seal will be unresponsive, which could lead to leakage issues. In extreme wear cases, the failure mode of a spring-energized seal can present a problem: if the sealing lip wears through, the spring can be exposed and potentially gall or scratch the hardware.

Bidirectional Sealing Capabilities

While O-Ring Energized Buffer and Scraper rings are pressure directional, standard rod and piston seals are inherently bidirectional. This means they are equally capable of sealing pressure on either side of the seal — ideal for double-acting pneumatic or hydraulic cylinders.

Spring Energized Seals are largely intended for only sealing on the open spring side. It would require two springs facing back-to-back to handle bidirectional pressure on a piston, which can complicate design and lead to "pressure trap" situations.

Conclusion: Finding Your Sealing Solution

There are some applications where making the choice between a Spring Energized Seal and an O-Ring Energized Seal is easy. Deep cryogenics or highly torque-sensitive rotary applications definitively point to a Spring Energized Seal. If temperature, media, and friction characteristics are not extreme, an O-Ring Energized Seal will likely be the more economical and space-efficient choice.

Eclipse has decades of experience designing and manufacturing Spring Seals and Seal Rings of all types. Contact us today to determine if your application could benefit from a custom-engineered PTFE sealing solution.

Temperature Ranges for Various Seal Materials: From NBR to PTFE

Thu, 19 Feb 2026 06:55:55 GMT

Selecting the correct seal material is one of the most critical decisions in any sealing application, and temperature is often the defining factor.

Operating outside a material’s allowable temperature range can result in hardening, softening, extrusion, accelerated wear, or catastrophic seal failure — even when pressure, surface finish, and gland design are otherwise correct.

From common elastomers like NBR to high-performance polymers such as PTFE, each sealing material responds differently to heat and cold. Understanding the temperature ranges of seal materials, how they behave at thermal extremes, and how temperature interacts with pressure and motion is essential for achieving long-term sealing performance.

Why Temperature Plays a Critical Role in Seal Performance

Temperature affects nearly every physical property of a sealing material. As temperatures rise, elastomers may lose elasticity, exhibit compression set, or undergo chemical degradation. Thermoplastics may soften, creep, or permanently deform. At low temperatures, materials can stiffen, shrink, or lose their ability to maintain sealing force against hardware.

In dynamic applications, frictional heat at the seal interface can significantly increase localized temperatures. Even when ambient system temperatures appear safe, surface speed and contact pressure can push materials beyond their thermal limits.

Installation practices also influence how well a seal tolerates thermal cycling, particularly when deformation or residual stress is introduced during assembly.

Elastomer Seal Materials and Typical Temperature Ranges

Elastomers are widely used due to their elasticity and ease of installation, but they generally offer narrower temperature windows compared to engineered polymers.

Nitrile Rubber (NBR)

NBR is one of the most common elastomers used for O-rings and static seals, thanks to its affordability and resistance to petroleum-based oils. However, its moderate temperature capability makes it susceptible to hardening at low temperatures and compression set at elevated temperatures, limiting its effectiveness outside general industrial environments.

Hydrogenated Nitrile (HNBR)

HNBR improves upon standard NBR by offering enhanced heat resistance, ozone resistance, and mechanical strength. It is often selected when higher operating temperatures or longer service life are required while maintaining elastomeric sealing behavior.

Fluorocarbon (FKM / Viton®)

FKM materials are frequently chosen for high-temperature sealing environments and chemically aggressive media. Their ability to maintain sealing force at elevated temperatures makes them a common upgrade when NBR or HNBR reach their limits, particularly in fuel, chemical processing, and aerospace applications.

Silicone Rubber

Silicone provides exceptional low-temperature flexibility and remains elastic where other elastomers stiffen. While its upper temperature range is comparable to FKM, lower tear strength and abrasion resistance often restrict its use in dynamic sealing applications.

Thermoplastic and Polymer Seal Materials

Thermoplastics rely on geometry, interference, and energization rather than elasticity to create a seal. These materials often outperform elastomers at temperature extremes.

PTFE (Polytetrafluoroethylene)

PTFE offers one of the widest operating temperature ranges of any sealing material and is nearly chemically inert. It performs reliably in both high-temperature and cryogenic applications where elastomers fail. Because PTFE lacks inherent elasticity, it is commonly used in mechanically energized designs such as spring-energized seals to maintain a consistent sealing force across wide temperature swings.

PTFE’s low coefficient of friction also helps minimize heat generation in rotary and reciprocating motion, extending seal life in demanding applications.

UHMW Polyethylene

UHMW provides excellent abrasion resistance and low friction, making it well-suited for reciprocating applications involving abrasive or particulate-laden media. Its relatively low upper temperature limit, however, restricts its use in elevated-temperature environments .

PEEK

PEEK is a high-performance thermoplastic capable of maintaining mechanical strength at elevated temperatures while offering excellent wear resistance and dimensional stability. It is often selected for high-temperature, high-pressure applications where stiffness and long-term reliability are critical.

Seal Material Temperature Range Comparison

Actual performance depends on pressure, motion, media, surface finish, and seal design.

Static vs Dynamic Sealing: Understanding Real Thermal Limits

Published temperature ranges are typically based on static conditions. In dynamic sealing — especially rotary motion — frictional heat can significantly reduce the effective operating temperature of a material.

For example, a seal material rated for 250°F static service may fail prematurely at much lower ambient temperatures when exposed to high surface speeds. PTFE-based solutions are often favored in these situations due to their thermal stability and low friction characteristics.

Installation methods also influence thermal performance , as improper stretching, rolling, or deformation can introduce stress that accelerates failure during thermal cycling.

The Impact of Thermal Cycling on Seal Materials

Many sealing applications do not operate at a single, steady temperature. Instead, seals are exposed to repeated heating and cooling cycles during startup, shutdown, washdowns, or process changes. This thermal cycling can be just as damaging as sustained high or low temperatures — and in some cases, even more so.

Elastomeric materials are particularly susceptible to thermal cycling. Repeated expansion and contraction can accelerate compression set, cause micro-cracking, or reduce sealing force over time. In dynamic applications, this loss of elasticity often leads to leakage during cold starts or premature failure at elevated temperatures.

Thermoplastics such as PTFE and PEEK handle thermal cycling differently. While they are less prone to compression set, they can experience creep or dimensional changes if gland designs do not properly accommodate expansion and contraction. This makes gland geometry, surface finish, and energization especially important in applications with frequent temperature swings.

Accounting for thermal cycling early in the design process helps prevent intermittent leaks, improves seal longevity, and ensures reliable performance across real-world operating conditions — not just steady-state temperature limits.

Low-Temperature and Cryogenic Sealing Considerations

Cold environments present unique challenges for sealing systems. Elastomers may lose elasticity and fail to energize properly at startup, while thermoplastics may contract or become brittle if the gland design does not account for thermal shrinkage.

Materials such as PTFE and UHMW are commonly used in cryogenic sealing applications due to their ability to remain stable at extremely low temperatures. Proper gland design and installation technique are essential to maintaining seal integrity under these conditions.

High-Temperature Sealing Challenges

At elevated temperatures, seals are exposed to increased risk of compression set, creep, chemical degradation, and accelerated wear. In these environments, material selection must be paired with appropriate gland geometry and, in many cases, mechanical energization.

Spring-energized PTFE seals and high-temperature polymers such as PEEK are frequently used to maintain sealing force when elastomers can no longer perform reliably.

Selecting the Right Seal Material by Temperature

While temperature is a primary driver in material selection, it should never be evaluated in isolation. Pressure, motion type, chemical exposure, installation method, and expected service life all play a role in determining long-term sealing success.

Material selection is most effective when these variables are considered early in the design process, reducing the risk of premature failure and costly redesigns.

Designing for Reliable Performance Across Temperature Extremes

Understanding temperature ranges for sealing materials from NBR to PTFE is fundamental to seal reliability. When properly specified, seals can perform across extreme environments for millions of cycles.

When misapplied, even advanced materials can fail prematurely.

Eclipse Engineering works with customers to evaluate how temperature interacts with the complete sealing system — from material selection and gland design to installation and long-term performance.

For assistance selecting the optimal seal material for your operating temperature range, contact Eclipse Engineering to collaborate on a solution engineered for durability, reliability, and performance.

Seal Installation Best Practices for Reliable Performance

Tue, 17 Feb 2026 15:09:09 GMT

Proper seal installation is one of the most critical — and most overlooked — factors in sealing system performance. Even the most precisely engineered seal can fail prematurely if it is nicked, twisted, overstretched, or improperly seated during assembly. For manufacturers and engineers working with O-rings, PTFE seals, urethane components, and rigid polymer seals, installation must be treated as an integral part of seal design, not an afterthought.

This guide builds on Eclipse Engineering’s original insights and expands them with additional best practices, material-specific considerations, and tooling strategies to support consistent, repeatable seal installation across low- and high-volume applications.

Why Seal Installation Directly Impacts Performance

Seal failure is often traced back to installation damage rather than material selection or design flaws. Common installation-related issues include rolled O-rings, cut sealing lips, uneven compression, and permanent deformation caused by excessive stretching. These problems can result in leakage, accelerated wear, and shortened service life.

Installation-related risks increase as seal cross-sections become heavier, materials become less elastic, or production volumes rise. Understanding how different polymers behave under stress is essential when planning an installation method.

Designing Seals with Installation in Mind

Successful installation begins at the design stage. Gland geometry, lead-in chamfers, surface finishes, and allowable stretch must all support safe insertion without damaging the seal. Poor surface finish or sharp edges can easily cut or abrade polymer seals during installation, increasing the likelihood of early failure.

Surface finish is particularly important for rigid and semi-rigid polymers, where installation forces are higher, and material compliance is limited .

O-Ring Installation: Simple but Easy to Get Wrong

O-rings are among the most forgiving seals to install, but they are also frequently damaged due to complacency. In low-volume applications, O-rings can often be installed by hand. However, in higher volumes, installer fatigue increases the likelihood of rolling, twisting, or uneven seating.

Lubrication, when compatible with the application, can significantly reduce friction during installation. Care must be taken to avoid excessive stretching, particularly for small cross-sections or tight rod glands. Even minor installation defects can lead to spiral failure or uneven wear over time.

Material-Specific Installation Challenges

Different seal materials require different installation strategies, and applying a one-size-fits-all approach often leads to damage.

PTFE and PTFE Blends

PTFE seals present some of the greatest installation challenges due to their low elasticity and tendency to permanently deform if mishandled. Most PTFE blends exhibit elongations greater than 100%, which allows them to be stretched over pistons using bullet tools and pusher rings.

After installation, resizing tools are typically required to remove induced stretch and restore the seal to its intended geometry. These challenges are consistent with the broader advantages and limitations of PTFE materials .

Urethane and Elastic Polymers

Urethane seals and other elastic polymers can often be stretched into place without permanent deformation. While the risk of surface damage is lower than with PTFE, care is still required to avoid nicking the sealing surface or overstressing the material. Heavy cross-sections may still benefit from guided installation tools to ensure even seating.

Rigid Polymers

Rigid plastics such as PEEK, Torlon, and UHMW require careful alignment and controlled installation forces. These materials do not tolerate sharp edges or uneven loading well, making tooling and gland design especially important. Installation constraints should be evaluated alongside operating parameters during material selection.

Specialized Installation Tools and When to Use Them

Installation tools are essential when working with high volumes, tight tolerances, or less forgiving materials. Bullet tools help guide seals over threads and sharp transitions, while pusher tools ensure uniform seating without point loading. Resizing tools are critical for PTFE seals, particularly after stretching during piston installation.

Using makeshift tools such as screwdrivers or metal picks introduces unnecessary risk and often results in surface damage that compromises seal integrity. Purpose-built tools help protect both the seal and the mating hardware while improving consistency across assemblies.

Installing Seals in Small Rod Glands

Small rod glands introduce unique challenges due to limited access and tight diameters. For O-rings, installers can often seat one edge of the seal and allow the rest to follow naturally. When access is restricted, a three-pronged tool can deform the seal into a kidney shape for insertion before gently seating it into the groove.

PTFE rings typically require additional care. After being formed into a kidney shape and inserted, an internal resizing tool is often necessary to restore the seal’s round profile and eliminate bends created during installation. Without proper resizing, sealing performance may be compromised.

Using Heat and Lubrication to Aid Installation

For PTFE and similar polymers, controlled heat can significantly improve pliability during installation. Heating seals in hot water softens the material temporarily, allowing it to be installed with less force. Because PTFE cools rapidly, installation must occur immediately after heating.

Lubrication can also reduce friction and minimize installation damage, even for materials that are not highly elastic. Any lubricant used must be compatible with both the seal material and the operating environment to avoid long-term performance issues.

Verifying Proper Seal Installation

Inspection is a critical final step in the installation process. Seals should be visually checked for nicks, uneven seating, or distortion. Directional seals must be oriented correctly, and glands should be free of debris or surface defects that could damage the seal during operation.

In high-reliability applications, verification procedures help ensure that installation variability does not undermine seal performance over time.

The Role of Training and Standardized Procedures in Seal Installation

Even with the correct seal design and installation tools, inconsistent installation practices can negatively impact performance. For high-volume or repeatable assembly processes, standardized installation procedures help ensure seals are handled, stretched, resized, and seated correctly every time.

Polymer seals such as PTFE, UHMW, and PEEK are especially sensitive to improper handling, which can introduce stress or deformation that shortens service life. Clear work instructions and basic operator training reduce variability, minimize damage, and improve consistency across production runs.

Treating seal installation as a controlled process — rather than an informal task — helps manufacturers improve reliability, reduce scrap, and maintain long-term sealing performance.

Ensuring Long-Term Seal Performance Starts with Installation

Seal installation is not a secondary consideration — it is a defining factor in how a seal performs in service. From material behavior and gland design to tooling and inspection, every installation decision influences reliability, wear life, and leakage control.

Eclipse Engineering regularly works with customers to develop installation strategies and custom tools that support repeatable, damage-free assembly.

By addressing installation challenges early, manufacturers can reduce scrap, improve consistency, and extend the service life of their sealing systems.

For expert guidance on seal installation, tooling, or material selection, contact Eclipse Engineering to collaborate with our team on a solution engineered for long-term performance and reliability.

The Pros and Cons of Using UHMW for Your Sealing Application

Mon, 12 Jan 2026 22:19:42 GMT

Ultra High Molecular Weight Polyethylene (UHMW) continues to be one of the most widely used polymer materials in industrial sealing — especially where wear, abrasion, or tough media conditions are present.

While PTFE and PTFE blends remain the flagship choices for many high-performance seals, UHMW offers a unique combination of durability, low friction, and cost-effectiveness that makes it a compelling option for engineers, designers, and procurement teams.

As a polymer with extremely long molecular chains, UHMW behaves differently from standard polyethylene grades (LDPE or HDPE). Its enhanced toughness, impact resistance, and chemical stability have made it indispensable in applications ranging from abrasive media seals to scraper seals , wear rings , and guide bearings.

Below, we expand on the advantages and drawbacks of UHMW as a sealing material — while offering engineering insight, design considerations, and real-world guidance to help determine whether UHMW is the right choice for your application.

The Advantages of UHMW

UHMW provides a combination of properties that make it ideal for sealing, guiding, and wear applications in demanding environments. It is especially effective when media is abrasive, contaminated, or chemically complex.

Exceptional wear, abrasion, tear, and cut resistance

UHMW’s durability is foundational to its appeal. Its long molecular chains give it exceptional toughness—significantly greater than many PTFE blends. In extremely abrasive environments, UHMW’s wear life can exceed PTFE by 10× or more.

This makes UHMW a smart choice in slurry pumping, ceramic-filled coatings, and mineral-processing equipment, where the media behaves like “liquid sandpaper.”

Its toughness also contributes to UHMW’s ability to handle abrasive and particulate-laden media without compromising performance.

Superior performance in abrasive and particulate-laden media

When dealing with abrasive or particulate-filled media, UHMW’s toughness enables it to maintain sealing integrity and prolong system uptime.

Alongside abrasion resistance, UHMW provides effective scraping and wiping capabilities that make it ideal for heavy-duty seal applications.

Effective scraping and wiping capability

UHMW maintains a sharp, point-loaded leading edge, making it ideal for scraper seals that must prevent buildup from sticky, gummy, or viscous media such as epoxies, resins, or slurries.

Combined with its low-friction properties, UHMW reduces heat and wear in dynamic applications, further extending seal life.

Low coefficient of friction

While not as low as PTFE , UHMW’s low friction helps reduce heat generation and enables operation with minimal lubrication. This helps avoid stick-slip and reduces overall system maintenance.

For applications where ultra-low friction is mandatory, engineers often compare UHMW to spring-energized PTFE seals — but UHMW often wins when abrasion resistance takes priority.

Beyond friction, UHMW’s chemical and moisture resistance broaden its usability across challenging media environments.

Chemical and moisture resistance

UHMW resists water, many solvents, dilute acids, and aggressive cleaning agents. Its exceptionally low moisture absorption makes it well-suited for humid or wet environments, including wastewater applications.

Virgin UHMW also meets food- and medical-grade requirements, aligning with Eclipse’s expertise in FDA- and medical-grade sealing .

Finally, UHMW is widely available and cost-effective, making it a practical option for high-volume and budget-conscious projects.

Cost-effectiveness and widespread availability

Compared to PTFE, PEEK, or UHMW alternatives, UHMW is significantly more economical. For high-volume OEM programs or cost-sensitive MRO schedules, UHMW provides outstanding value.

While these advantages are compelling, it’s equally important to understand UHMW’s limitations to avoid potential performance issues.

The Disadvantages of UHMW

Despite its strengths, UHMW is not the right material for every application. Engineers should weigh its limitations carefully during material selection.

Limited high-temperature performance

UHMW begins to lose strength around 150°F (65°C) and has a continuous operating limit near 180°F (82°C). For high-temperature or high-speed rotary applications, PTFE, PEEK, or engineered composites outperform UHMW.

This temperature sensitivity also restricts UHMW’s suitability for high-speed rotary sealing.

Not suitable for high-speed rotary sealing

Rotary motion generates frictional heat at the seal interface. Even at room temperature, this can push UHMW beyond its thermal limits and cause distortion, creep, or premature wear.

In these environments, spring-energized seals or PTFE rotary seals are generally recommended.

UHMW’s high coefficient of thermal expansion can further impact dimensional stability in precision applications.

High coefficient of thermal expansion (CTE)

UHMW exhibits significant dimensional changes with fluctuating temperatures. For tight-tolerance components, this can result in poor sealing performance or binding.

Additionally, machining and processing challenges make UHMW more difficult to fabricate for precision applications.

Machining and processing challenges

Because UHMW chips into long, continuous strands and is susceptible to heat distortion, precision machining requires expertise in polymer manufacturing. Eclipse frequently advises customers on best practices through its custom-engineered solutions.

Its lower stiffness also makes UHMW less suitable for heavy static loads.

Lower stiffness and deformation risk

Under heavy static load, UHMW can creep or deform. In applications requiring structural rigidity or long-term dimensional stability, harder polymers such as Nylon, acetal, or PEEK may be more appropriate.

Understanding these limitations sets the stage for knowing when UHMW is the right choice — and when alternative materials should be considered.

When UHMW Is the Right Choice — and When to Look Elsewhere

UHMW excels in applications involving:

Abrasive or particulate-filled media
Reciprocating motion (piston rods, cylinders)
Scraper seals and wipers
Low-lubrication or no-lubrication environments
Food, beverage, and pharma conditions
Cost-sensitive, high-volume parts

UHMW may not be suitable when:

Temperatures exceed 150–180°F
Rotary speeds produce high frictional heat
Dimensional precision is critical
Heavy static loads require higher stiffness

If UHMW does not meet the requirements, we may recommend PTFE, PEEK, or specialized engineered polymer composites.

Once the right application is identified, following best practices in design ensures UHMW performs optimally.

Best Practices for Designing with UHMW Seals

1. Account for thermal expansion in gland design

Because UHMW expands significantly with heat, glands must account for expansion, especially in dynamic applications.

Machining allowances also play a critical role in ensuring dimensional accuracy.

2. Allow for machining tolerances

Custom-machined UHMW components may require stress relief or dimensional allowances to ensure accuracy after processing. Eclipse’s custom machining services can assist with this step.

Material selection should also match motion requirements for optimal performance.

3. Use UHMW in reciprocating rather than rotary applications

Piston seals, wipers, guide rings, and wear surfaces are ideal candidates. Selecting the proper grade ensures chemical and compliance requirements are met.

4. Choose the correct UHMW grade

Options include:

Virgin UHMW (FDA/food-grade)
Reprocessed UHMW for cost-sensitive applications
High-wear modified grades

Even with ideal design, planning for maintenance ensures longevity.

5. Plan for maintenance & wear monitoring

Even UHMW will wear down in abrasive applications. Designing components for easy replacement increases uptime and reduces unexpected failures.

Understanding these best practices sets the stage for real-world applications across industries.

Real-World Use Cases & Industries Where UHMW Seals Excel

UHMW is used widely across industries where abrasion resistance, moisture resistance, reliability, and cost-efficiency are top priorities.

Paint, coating & slurry equipment: UHMW scraper seals, guide rings, and wipers dramatically outperform softer plastics.
Resin, epoxy & adhesive dispensing: UHMW maintains wiping edges and prevents buildup.
Food, beverage & pharmaceutical processing: Virgin UHMW is FDA-compliant and chemically inert.
Manufacturing equipment wear components: Wear rings and guide bearings benefit from low friction and durability.
Marine, coastal & wastewater environments: Low moisture absorption extends service life.

These use cases highlight how UHMW can deliver reliable, cost-effective performance when applied correctly.

Is UHMW Right for Your Application?

UHMW is not a universal material, but when specified correctly, it delivers excellent value in terms of longevity, abrasion resistance, friction performance, and total cost of ownership.

Eclipse Engineering’s experts help engineers and procurement teams evaluate whether UHMW — or an alternative like PTFE, PEEK, or engineered composites — is the best choice for your temperature, pressure, media, and motion requirements.

If you're evaluating UHMW for your next project, we’re here to help. Contact our engineering team , and we’ll review your specifications, recommend optimal materials, and engineer a solution built for long-term performance.

The History and Ingenuity of the Buffer Ring: Part 2

Sun, 14 Dec 2025 23:04:00 GMT

The History and Ingenuity of the Buffer Ring: Part II

In the 1980s, the Buffer Ring began to gain real traction in the hydraulic sealing market. Customers quickly recognized that the addition of this single component dramatically enhanced overall system performance.

While the manufacturing cost increased slightly, the trade-off was worth it: lower operating temperatures, smoother motion, quieter operation, and most notably, a significant reduction in warranty claims and field failures.

The Buffer Ring proved that a small addition to the rod gland could have an outsized impact on hydraulic cylinder efficiency and longevity.

Buffer rings can also be manufactured as piston seals, though in that configuration, two would be required to operate in both directions. In most cases, a small amount of internal leakage across a Teflon® piston seal is acceptable — since it occurs entirely within the system.

The History of the Buffer Ring

The Buffer Ring originated in Germany and was initially designed to be used with a standard O-ring energizer. But when the design was tested in the United States, engineers made an important discovery: replacing the O-ring with a square ring energizer increased the sealing load by nearly 30%, while also reducing leakage during cylinder extension.

At the time, the gland geometries for the Buffer Ring had already been standardized, so designers simply adapted the configuration — reducing the elastomer width to make room for the new square ring and PTFE sealing element .

This adjustment opened the door to stacked Buffer Ring designs, where two rings could be used without the need for a traditional U-cup.

When paired with a double-acting wiper, leaked oil could be recaptured and returned into the system, creating a more self-contained and efficient hydraulic circuit.

In clean operating environments, these cylinders could even function without an external wiper — though a minor amount of leakage over time was expected.

For construction and heavy equipment applications, however, the addition of a wiper remained standard practice to keep contaminants out.

Back to the Square Ring

A small engineering debate emerged between German and American designers over which energizer type — O-ring or square ring — provided superior performance.

The German design had international recognition, but American engineers favored the square ring for its greater sealing load and stability. In the end, a compromise was reached: increasing the O-ring squeeze achieved better sealability without abandoning the traditional European design.

The decision wasn’t purely technical — square rings weren’t widely available in Europe, and the “not-invented-here” mentality influenced adoption. Still, both versions performed well in the field, and the Buffer Ring continued to evolve as a global sealing solution.

From a designer’s perspective, the square ring remains a strong choice. While over-squeezing an O-ring can shorten its lifespan, these systems always include a secondary sealing element, ensuring redundancy and preventing catastrophic failure.

How Does a Buffer Ring Work?

There are two prevailing schools of thought about how the Buffer Ring functions — and both play a role in its effectiveness.

A Teflon® piston seal is a simple cross-section with chamfered edges for installation.

Under pressure, oil can move across the seal interface due to micro-irregularities in the surface finish. With the Buffer Ring, this leakage is not a flaw but a controlled process that helps balance pressure and lubricate the system.

When the rod retracts into the cylinder, the Buffer Ring rocks in its groove.

The back-angle contact side of the seal changes geometry slightly, compressing the trapped oil and pushing it back toward the low-pressure side. This “rocking” or “pivoting” motion effectively pressurizes the oil film and recirculates it into the system — maintaining lubrication while preventing pressure traps.

Some engineers argue that this effect is caused primarily by geometry and surface finish, while others attribute it to the fluid dynamics of pressure equalization. In reality, both mechanisms likely contribute to the Buffer Ring’s unique self-correcting action.

The outcome is clear: less leakage, lower friction, and a longer-lasting seal system than traditional O-ring or U-cup designs.

The History and Ingenuity of the Buffer Ring: Part II

The Buffer Ring proved that a small addition to the rod gland could have an outsized impact on hydraulic cylinder efficiency and longevity.

The History of the Buffer Ring

This adjustment opened the door to stacked Buffer Ring designs, where two rings could be used without the need for a traditional U-cup.

When paired with a double-acting wiper, leaked oil could be recaptured and returned into the system, creating a more self-contained and efficient hydraulic circuit.

In clean operating environments, these cylinders could even function without an external wiper — though a minor amount of leakage over time was expected.

For construction and heavy equipment applications, however, the addition of a wiper remained standard practice to keep contaminants out.

Back to the Square Ring

A small engineering debate emerged between German and American designers over which energizer type — O-ring or square ring — provided superior performance.

How Does a Buffer Ring Work?

There are two prevailing schools of thought about how the Buffer Ring functions — and both play a role in its effectiveness.

A Teflon® piston seal is a simple cross-section with chamfered edges for installation.

When the rod retracts into the cylinder, the Buffer Ring rocks in its groove.

The outcome is clear: less leakage, lower friction, and a longer-lasting seal system than traditional O-ring or U-cup designs.

The Role of Bushings and Support Elements

In addition to the Buffer Ring, bushings and wear bands play an essential role in stabilizing the rod and maintaining proper alignment.

Typically, split Teflon® bushings are used on either side of the Buffer Ring assembly — one ahead of the first ring and another between the Buffer Ring and U-cup. This arrangement distributes side-load forces across a wider surface area and keeps the bushings properly lubricated.

When applications demand higher load-bearing capacity, alternative materials such as filled PTFE composites , PEEK, or thermoplastic bearings can support pressures from 1,000 PSI to over 40,000 PSI compressive.

These advanced materials extend system life in high-pressure, high-cycle environments like aerospace, energy, and heavy-duty hydraulic systems.

Modern Innovations in Buffer Ring Design

Since its introduction, the Buffer Ring has continued to evolve alongside advances in materials science and manufacturing technology.

Today’s designs benefit from precision machining, improved groove geometry, and specialized PTFE blends that outperform earlier versions.

Key Modern Enhancements Include:

Filled PTFE and polymer composites that resist extrusion and wear.
Finite Element Analysis (FEA) for optimizing groove geometry and pressure relief.
Hybrid designs integrating backup rings or anti-extrusion devices for ultra-high pressure.
Precision micro-machining for consistent dimensions and smoother finishes.

At Eclipse Engineering, our buffer rings are engineered with precision tolerances to meet specific pressure, speed, and temperature requirements.

Every design is backed by decades of hydraulic sealing expertise and advanced testing to ensure reliability in real-world conditions.

Comparing Buffer Rings to Modern Sealing Technologies

While the Buffer Ring remains a cornerstone of hydraulic seal design, it’s important to recognize its place in the broader landscape of sealing solutions.

Compared to U-cups, rod seals, and O-rings, the Buffer Ring is unique because it acts as a pressure modulator rather than a full barrier. It works in tandem with other seals to distribute load, regulate lubrication, and prevent extrusion.

In modern applications, engineers often pair Buffer Rings with custom PTFE seals or O-ring energized profiles, especially in systems where pressure fluctuations, side loads, and extreme temperatures are present.

These combinations provide both sealing integrity and dynamic response under demanding conditions.

Applications of Buffer Rings in Today’s Industries

Buffer Rings have found their way into nearly every industry where hydraulic or pneumatic power is used. Common applications include:

Heavy Equipment & Construction Machinery – backhoes, loaders, and excavators.
Agricultural Equipment – hydraulic actuators and control systems.
Aerospace & Defense – landing gear, actuators, and hydraulic flight systems.
Industrial Manufacturing – presses, molding systems, and automation cylinders.
Oil & Gas – drilling and valve actuation systems requiring high-pressure sealing.

Their ability to extend seal life, prevent leaks, and maintain smooth operation makes them indispensable in modern engineering design.

Why Material Science Still Matters

As sealing requirements evolve, so do the materials that make Buffer Rings more durable, flexible, and chemically resistant.

Modern versions use blends of bronze-filled PTFE, carbon-filled PTFE, UHMWPE, and PEEK composites for different operating conditions.

Choosing the correct compound remains one of the most important decisions in any sealing design. Eclipse Engineering’s team evaluates temperature, media compatibility, motion type, and system pressure to select or develop the right formulation for each project.

Partnering with Eclipse Engineering

At Eclipse Engineering, we continue to advance the legacy of the Buffer Ring with custom designs, advanced materials, and precision manufacturing.

Our engineers specialize in developing complete sealing systems — including buffer rings, U-cups, O-rings, and bearings — that meet the toughest performance and environmental demands.

From prototype development to full-scale production, every Eclipse product is manufactured in the USA and backed by a commitment to performance, innovation, and reliability.

Ready to Enhance Your Hydraulic System?

Contact Eclipse Engineering to speak with one of our sealing experts and discover how a custom-engineered buffer ring can improve system performance, reduce downtime, and extend component life.

The History & Evolution of Buffer Rings: How PTFE Transformed Hydraulic Seal Design

Sun, 16 Nov 2025 18:23:12 GMT

Hydraulic sealing technology has come a long way since the early days of heavy equipment engineering. In high-pressure systems — like those found in construction, mining, and agricultural machinery — seal performance directly impacts efficiency, reliability, and equipment longevity.

When seals fail, the result isn’t just a small oil leak; it can mean costly downtime, safety hazards, and extensive field repairs.

That’s why the development of the buffer ring marks such a pivotal moment in the history of hydraulic seal design. This simple yet ingenious component helped solve one of the industry’s biggest challenges: protecting critical seals from damaging pressure spikes, heat, and extrusion — all while extending system life and maintaining leak-free performance.

At Eclipse Engineering, we see the buffer ring as a turning point in modern sealing systems. The same principles that made it revolutionary in the 1970s still guide how we design and manufacture custom PTFE seals, U-cups, and buffer rings today.

Our engineers continue to refine materials, profiles, and manufacturing processes to deliver high-performance sealing solutions for hydraulic systems operating in the most demanding conditions.

In this post, we’ll explore the origins of the buffer ring, how it works, and why its design forever changed the way engineers think about hydraulic sealing solutions.

Why the Buffer Ring Revolutionized High-Pressure Hydraulic Seal Design

Back in the mid-1970s, an engineer named Roy Edlund of Busak & Luyken designed a high-pressure seal with an unexpected but revolutionary behavior: it would rock in the groove under pressure. This effect occurred when the rod was retracted into the cylinder, creating pressure on the retract side.

The material used for this innovative seal was a bronze-filled PTFE (Teflon®) — a material that could resist extrusion and provide long seal life. However, because the seal was made from filled Teflon, a small amount of oil would leak under the lip as the cylinder extended.

Surprisingly, this wasn’t a flaw — it was a feature. When the rod retracted, the buffer ring would rock slightly to the low-pressure side, forcing leaked oil back into the retract side of the cylinder.

This self-correcting motion not only reduced leakage but also extended the life of hydraulic seals, transforming how engineers approached high-pressure hydraulic sealing systems.

Today, this component is known as the Buffer Ring, and it helped usher PTFE seals into nearly every high-pressure hydraulic application we see today.

Pre-Buffer Ring Sealing Problems

Before the advent of the buffer ring, manufacturers of high-pressure hydraulic systems—like those used in backhoes, cranes, and heavy machinery—were facing frequent seal failures long before their warranty periods ended.

The standard urethane U-Cup seal performed adequately at moderate pressures, creating a near-zero-leak system under normal conditions. However, as bulk oil temperatures rose and pressure spikes occurred, these seals would degrade rapidly.

Common Problems Before Buffer Rings:

Pressure spikes causing urethane to crack and fail prematurely
Heat buildup accelerating material wear
Frequent downtime and costly field repairs for OEMs
Inefficient energy use due to internal leakage and friction

These issues didn’t just shorten seal life — they affected entire hydraulic system performance, leading to increased maintenance costs and reduced operational efficiency.

The Buffer Ring Solution

The Buffer Ring addressed these issues with remarkable simplicity. By adding a secondary sealing element in front of the U-Cup, engineers could dramatically reduce pressure spikes, lower system friction, and extend seal life.

This dual-seal configuration acted as both a pressure buffer and a lubrication regulator, allowing a controlled amount of oil to reach the U-Cup for cooling and reduced friction.

Key Benefits of Buffer Rings:

Extends U-Cup life by reducing pressure load
Lowers bulk oil temperature in the hydraulic system
Reduces system friction for smoother operation
Improves equipment uptime and lowers warranty costs

The results were clear: longer-lasting seals, fewer failures, and lower maintenance costs — a combination that quickly made PTFE buffer rings a staple in hydraulic cylinder design.

How the Buffer Ring Works

At first, many engineers were skeptical. How could placing one seal in front of another reduce pressure without creating a trap?

The answer lies in the controlled leakage mechanism that defines buffer ring design.

The Science Behind It:

The buffer ring intentionally allows micro-leakage, ensuring the U-Cup remains lubricated.
This leakage prevents heat buildup and material degradation.
During retraction, the buffer ring “rocks” slightly, pushing oil back into the system — maintaining balance and preventing trapped pressure.

This unique dynamic allows the U-Cup to operate in a low-pressure, low-temperature, and well-lubricated environment, dramatically extending its operational life.

For hydraulic cylinder manufacturers, the buffer ring meant higher reliability and fewer field failures — all while simplifying maintenance protocols.

Why Material Selection Matters in Buffer Rings

While early buffer rings used bronze-filled Teflon, modern versions leverage advanced polymer blends that improve flexibility, wear resistance, and compatibility with different fluids.

Common Buffer Ring Materials:

Bronze-filled PTFE: Excellent wear and extrusion resistance for high-pressure applications.
Glass-filled PTFE: Improves stiffness and temperature performance.
Carbon-filled PTFE: Reduces friction, ideal for dynamic sealing.
UHMWPE or PEEK composites: Used in extreme pressure or chemical environments.

Choosing the right material depends on the operating pressure, temperature, media, and motion type (static, reciprocating, or rotary). Eclipse’s in-house engineers often customize these materials to achieve optimal seal performance and longevity.

Comparing Buffer Rings to Other Hydraulic Seals

While buffer rings are critical in high-pressure hydraulic applications, they serve a distinct purpose compared to other seals.

This comparison illustrates how the buffer ring acts as a pressure regulator, rather than a primary barrier — a distinction that has made it indispensable in modern hydraulic seal systems.

Design Considerations for Hydraulic Buffer Rings

To ensure optimal performance, buffer rings must be carefully matched to the system’s design parameters.

Key Design Factors:

Groove geometry: Must allow slight rocking and oil return flow.
Surface finish: Polished to minimize friction and leakage.
Temperature and pressure range: Ensure compatibility with seal material.
Lubrication path: Must support oil return to maintain seal life.

At Eclipse Engineering, these factors are analyzed during the seal design process, ensuring that every hydraulic sealing package meets or exceeds system requirements.

The History and Legacy of the Buffer Ring

The Buffer Ring began as a patented design under the name Stepseal® , owned by Trelleborg. Though the original patents have long since expired, the design remains a cornerstone in modern hydraulic sealing technology.

Refinements, like removing the corner heel to prevent extrusion in ultra-high-pressure systems, have kept this design relevant for nearly 50 years.

Today, Eclipse continues to evolve this technology through custom seal design, advanced materials, and precision manufacturing in Erie, Colorado — ensuring each solution meets demanding application needs.

Eclipse Engineering: Custom Buffer Rings for Modern Hydraulic Systems

At Eclipse Engineering, we design and manufacture custom buffer rings, U-cups, and bearings for hydraulic cylinders and actuators across industries — from aerospace to heavy equipment .

Our engineers can develop a complete sealing solution tailored to your system’s unique needs, using the right blend of PTFE, polymer composites, and energizers to achieve the perfect balance of sealing reliability and cost efficiency.

All Eclipse products are manufactured in the USA, combining decades of experience with cutting-edge sealing technology.

Ready to improve your hydraulic system performance? Contact Eclipse Engineering today to speak directly with an engineer about your application.

Why Surface Finish Matters in Polymer Seal Performance

Fri, 26 Sep 2025 02:20:36 GMT

Picture this: You have an application using a standard O-Ring. The O-Ring seals great, but is wearing out very quickly, and the friction is far exceeding the goals of the system. You retrofit a fancy PTFE spring-energized seal that costs 1000 times more than the O-Ring… only to find out it leaks!

Did you get a defective seal? Is the seal designer incompetent? Is the raw material bad?

Actually, everything about the design and manufacturing of the spring-energized seal could be perfect, and you could still find yourself with leakage.

While blaming the seal might be your first instinct, the leakage, in fact, could have nothing to do with the seal itself — and everything to do with the surface finish of the hardware it’s trying to seal against.

How is Surface Finish Defined?

If you’ve seen an image of a seemingly smooth surface under a high-power microscope, you know that what looks flawless to the naked eye can actually be full of peaks, valleys, cracks, and imperfections.

These microscopic features of any surface are particularly important to sealing performance. Surface finish is a complex and in-depth subject that has many facets of analysis to describe the texture or topography of a surface.

In the world of seals, surface roughness is typically used to describe the finish condition of a sealing surface. The Roughness Average (Ra) value is the most commonly used parameter, expressed in microinches or micrometers. The lower the value, the smoother the surface.

Ra is generally used for historical or traditional purposes, and not for its merit, as it doesn’t fully define a surface. It leaves the possibility of a surface with high peaks and low valleys to still average out to a reasonable number. (Though in most modern finishing techniques, this would be an undesirable and unacceptable condition.)

These peaks and valleys are really what matter to sealing performance, especially when using polymer-based seals. These are the microscopic gaps that the seal is responsible for closing off.

Why Surface Finish is More Critical for Polymer-Based Seals

If you’re accustomed to using O-Rings or elastomeric seals, hardware surface finish might be considered an afterthought. In many cases, an “as machined” finish will be perfectly fine for an O-Ring to seal against.

An O-Ring is much softer and more compliant than PTFE and most other polymers. A rubber-like material can easily conform to rough and uneven surfaces to provide effective sealing.

While PTFE might be considered a relatively soft plastic, it’s still many times harder than most O-Ring materials. Rather than “squishing” into a microscopic gap in the surface to seal it, a harder material will merely bridge the imparity, creating a leak path.

In most cases, surface finishes intended for an O-Ring will result in unacceptable leakage when used with a PTFE or polymer-based seal.

What Surface Finishes are Recommended for Polymer-Based Seals?

Surface finish requirements will largely be dependent on the media to be sealed and the dynamics of the system.

Recommendations for a static seal that’s meant to work in peanut butter will be very different from a reciprocating valve sealing liquid oxygen.

Below is a table with standard recommendations based on some common media and dynamic situations. These provide a general idea of the surface finishes needed, but please consult us for application-specific suggestions.

It’s important to note that the best surface finish achievable from a typical turning process is usually a 16 µin Ra. In many cases, it won’t be better than a 32 µin.

Milling operations can result in even poorer finishes. Cast surfaces are also unlikely to have finishes better than these.

This is important because, aside from sealing a very viscous media in a static situation, an “as machined” or “as cast” surface finish is unlikely to be sufficient for a polymer seal. Some form of post-process surface treatment will almost always be necessary.

Processes such as grinding, honing, polishing, and lapping can achieve the required finish, though these add significant cost to hardware. Depending on the configuration, polishing the inside of a groove deep inside a housing may be very challenging. It’s usually easier to get better finishes on rod surfaces rather than bores.

Therefore, given the option, it’s typically better to keep the dynamic sealing surface on a rod or shaft.

Cost–Benefit Analysis of Surface Finishing for Polymer Seals

Surface finishing can significantly impact both the cost of hardware and the reliability of the seal. For many projects, engineers must decide whether the added expense of finishing operations is justified by the performance benefits.

For example:

In a general industrial application where a small amount of leakage is acceptable, a turned surface at ~32 µin Ra may perform adequately.
In aerospace or medical devices, however, where leakage tolerance is close to zero, investing in polishing or lapping can mean the difference between mission success and costly failure.

The decision often comes down to risk versus return. Investing in better finishes increases upfront manufacturing cost but reduces the risk of failure, downtime, or warranty claims.

At Eclipse, we work with customers to assess the acceptable level of leakage for their application and recommend the most cost-effective surface finish that still ensures reliability.

Surface Treatment Methods to Improve Seal Performance

When a machined or cast surface doesn’t meet the finish requirements for PTFE or polymer seals, additional surface treatments can dramatically improve sealing performance.

Common post-processing methods include:

Grinding : Achieves finishes down to 8 µin Ra, ideal for shafts and rods.
Honing : Creates crosshatched bore surfaces that improve lubrication and wear resistance.
Polishing : Delivers ultra-smooth surfaces, critical for medical, cryogenic, or semiconductor sealing.
Lapping : Provides some of the smoothest finishes possible (sub-1 µin Ra), used in aerospace and high-vacuum systems.

The right treatment depends on geometry, media, and system dynamics. Each method adds cost, but when balanced correctly, they provide the performance improvements needed to ensure long-term sealing success.

What is Acceptable Leakage?

It’s important to note that surface finish recommendations can vary greatly depending on specific applications. Surface finishes may need to be more or less stringent based on the leakage goals of the system.

While any polymer seal will likely never achieve a “zero leak” situation despite the best surface conditions, it can be expected that the better the finish, the tighter the leakage control.

This is not always the case with O-Rings, where finishes that are too smooth can actually hurt sealing performance and significantly increase friction in dynamic situations.

Generally, with PTFE or polymer-based seals, the finishes “can’t be too good.”

But as stated earlier, achieving highly polished surfaces in certain hardware configurations can be very costly. It’s up to you to determine if the cost of achieving these finishes is needed to meet the goals of the application.

Eclipse has many customers who use finishes worse than recommended because leakage isn’t critical. For example, a customer constructing a standard air cylinder might typically use O-Rings for all primary seals.

In cases where operating temperature is too high for O-Rings, they may use an Eclipse PTFE spring-energized seal . Here, improving hardware finishes isn’t necessary, because slightly more leakage only results in a small decrease in efficiency — an acceptable tradeoff.

On the other end of the spectrum, finishes might need to be much better than recommended in critical sealing applications.

For example: a spring-energized seal used to contain cryogenic propellants on long-term space exploration missions. Any leakage here represents a mission limitation and liability. In this case, special techniques and materials might be necessary to provide the best finish possible.

The Future of Surface Engineering in Sealing Applications

Advancements in manufacturing are opening the door to new ways of achieving the ultra-smooth surfaces required for high-performance polymer seals.

Emerging approaches include:

Laser Surface Texturing (LST): Controlled micro-patterning to reduce wear and enhance lubrication.
Plasma Surface Treatments: Altering surface chemistry to reduce friction and improve sealing compatibility.
Additive Manufacturing (3D Printing) Finishing: Post-processing techniques such as abrasive flow machining or electro-polishing that transform rough 3D-printed parts into seal-ready components.
Diamond-Like Carbon (DLC) Coatings: Thin coatings that improve wear resistance, reduce friction, and create smoother interfaces.

These methods, once limited to aerospace or semiconductor industries, are becoming more accessible across sectors like energy storage, medical devices, and industrial machinery.

Eclipse stays at the forefront of these advancements, helping customers leverage modern surface engineering methods to achieve sealing success without excessive cost or complexity.

Eclipse Is Here to Help

Eclipse understands the implications of requiring polished surface finishes and that these kinds of operations are not always possible. We’re here to utilize our vast selection of seal materials and our decades of experience in seal design to provide a solution to even the most challenging applications.

For example, Eclipse had a customer looking for a seal for a large, heavy chamber door. The groove for the seal was a milled surface, and it would not be practical — or even really possible — to remove the door and perform a polishing process to improve the finish.

By careful seal material selection and unique design characteristics, we were able to provide a sealing solution that met their leakage requirement goals.

While recommendations are useful guidelines and starting points, they are not necessarily the end of the story. Contact Eclipse today to put our advanced knowledge base and manufacturing expertise to work for your most difficult sealing challenges.

Advantages and Disadvantages of PTFE O-Rings: A Complete Guide

Tue, 23 Sep 2025 19:08:19 GMT

Polytetrafluoroethylene (PTFE) O-rings are a trusted sealing solution in industries where extreme conditions demand more than standard elastomers can handle.

From aerospace and automotive to chemical processing and medical devices, PTFE O-rings offer unique advantages that make them indispensable — but they also come with trade-offs that engineers must carefully consider.

In this guide, we’ll cover everything you need to know about PTFE O-rings: their strengths, limitations, best applications, and how to choose the right seal for your needs.

What Are PTFE O-Rings? An Inside Look at Fluoropolymer Seals

PTFE is a synthetic fluoropolymer known for its exceptional chemical resistance, wide operating temperature range, and low friction properties. These characteristics make PTFE O-rings an ideal choice for demanding sealing applications where traditional rubber compounds fail.

Unlike elastomer O-rings, which can degrade under harsh chemicals or elevated heat, PTFE O-rings maintain integrity and performance in extreme environments. However, PTFE’s rigidity and limited elasticity also mean that it behaves differently in a seal groove, requiring careful design and installation considerations.

PTFE Grades and Fillers: Tailoring Performance for Specific Needs

Not all PTFE O-rings are created equal. While virgin PTFE provides outstanding chemical resistance and purity, filled PTFE grades offer improved mechanical properties that address some of PTFE’s weaknesses. By adding reinforcing materials to the polymer, manufacturers can optimize O-rings for specialized conditions:

Glass-filled PTFE : Improves dimensional stability and reduces cold flow, making it a strong choice for high-pressure static applications.
Carbon-filled PTFE : Enhances wear resistance and compressive strength, useful in dynamic sealing environments.
Graphite-filled PTFE : Provides better thermal conductivity while retaining PTFE’s chemical inertness.
Bronze-filled PTFE : Offers higher strength and reduced creep, though with slightly lower chemical resistance.

Choosing the right PTFE blend allows engineers to fine-tune performance for their exact application, ensuring the O-ring is not just durable but also efficient in its operating environment.

Unmatched Advantages of PTFE O-Rings

PTFE O-rings provide numerous benefits that make them the go-to choice for engineers and manufacturers:

Chemical Resistance – PTFE resists nearly all aggressive chemicals, solvents, and acids, making it suitable for highly corrosive environments.
Wide Temperature Range – Performs reliably from cryogenic conditions up to approximately 500°F (260°C).
Low Friction and Non-Stick Properties – PTFE’s smooth surface minimizes wear and reduces energy loss in dynamic applications.
Non-Contaminating and Inert – Ideal for food, pharmaceutical, and medical manufacturing where purity is critical.
Exceptional Shelf Life – Unlike elastomers, PTFE does not degrade or age, ensuring long-term reliability in storage and use.

PTFE O-rings shine where chemical exposure, high temperatures, and durability are non-negotiable.

Performance Trade-Offs: Disadvantages You Should Know

While PTFE O-rings deliver unmatched benefits, they also have limitations:

Lack of Elasticity – PTFE does not compress or stretch like elastomers, which can make sealing more difficult in certain applications.
Cold Flow / Creep – Under sustained pressure, PTFE can deform permanently, leading to leakage over time.
Installation Challenges – PTFE’s rigidity makes it prone to cracking or distortion if improperly installed.
Poor Low-Pressure Sealing – Without elasticity, PTFE O-rings may not seal effectively in low-pressure static applications.

Understanding PTFE’s weaknesses is critical to designing grooves, selecting backup rings, and ensuring proper installation.

Cost Considerations: PTFE vs Elastomers and Hybrids

Beyond performance, cost plays a significant role in seal selection. PTFE O-rings generally cost more than traditional elastomers like NBR, EPDM, or Viton®, both because of the raw material and the machining required for production.

However, the initial price tells only part of the story. PTFE’s longer service life, resistance to chemical attack, and ability to operate in extreme environments often reduce overall lifecycle costs.

For industries where downtime or seal failure is extremely costly — such as aerospace, semiconductor, or pharmaceutical manufacturing — PTFE can deliver a better return on investment despite higher upfront expenses.

In contrast, elastomers remain the most economical choice for standard operating environments, especially when flexibility and resilience are more critical than chemical or temperature resistance.

Best Uses for PTFE O-Rings vs Elastomers

When should you choose PTFE over traditional elastomer O-rings like NBR, EPDM, or Viton®?

Choose PTFE O-Rings When:

Your system operates in extreme chemical environments.
High operating temperatures exceed elastomer limits.
Friction reduction is critical for performance.
Long-term storage and shelf stability are required.

Stick with Elastomers When:

You need flexibility and resilience in the seal.
Applications involve frequent dynamic movement at low pressures.
Cost efficiency is more important than chemical resistance.

PTFE and elastomer O-rings each excel in different areas. Choosing the right material depends on your application priorities.

Industry-Specific Applications and Case Examples

PTFE O-rings aren’t just versatile — they solve industry-specific problems where elastomers fall short:

Aerospace : Fuel systems, hydraulic controls, and engine components rely on PTFE to withstand aggressive fuels and wide thermal cycles.
Automotive : PTFE O-rings in transmissions and emission systems prevent seal degradation from high heat and chemical exposure.
Medical & Pharmaceutica l: Non-reactive and FDA-compliant PTFE ensures sterility in pumps, valves, and drug delivery systems.
Food & Beverage : PTFE’s non-stick properties prevent flavor carryover and contamination while meeting safety standards.
Chemical Processing : Strong resistance to acids, solvents, and reactive gases ensures uptime in critical manufacturing equipment.

By tailoring PTFE O-ring solutions to each industry’s unique needs, engineers can maximize performance, safety, and reliability.

When to Choose PTFE O-Rings vs Spring-Energized Seals

Spring-energized seals are an alternative when PTFE alone cannot provide adequate sealing. These seals combine a PTFE jacket with a metallic spring, which provides the elasticity PTFE lacks.

Advantages of Spring-Energized Seals:

Maintain sealing force even under low pressures.
Handle extreme dynamic applications better than plain PTFE O-rings.
Resist creep deformation thanks to spring support.

When to Use Spring-Energized Seals Instead of PTFE O-Rings:

In cryogenic applications where contraction reduces sealing force.
For vacuum applications requiring reliable leak-tight sealing.
When system pressure cycles frequently.

If your application demands both PTFE’s durability and elastomer-like sealing force, spring-energized seals may be the better fit.

Proper Installation & Long-Term Care of PTFE O-Rings

To get the most from PTFE O-rings, careful installation and maintenance practices are essential:

Groove Design – Ensure the groove is designed to account for PTFE’s lack of elasticity and cold flow.
Lubrication – Use compatible lubricants to reduce installation friction and risk of cracking.
Backup Rings – Employ backup rings in high-pressure applications to prevent extrusion and creep.
Inspection & Replacement – Regularly inspect seals for deformation, creep, or damage and replace as needed.

Proper installation extends service life and helps PTFE O-rings perform reliably in challenging conditions.

Custom PTFE O-Ring Solutions from Eclipse Seal

Not every sealing challenge can be solved with an off-the-shelf solution. That’s why Eclipse Seal specializes in custom PTFE sealing products designed to meet exact performance requirements.

Our capabilities include:

Custom-compounded PTFE blends for unique environments.
FDA, USP Class VI, and other regulatory-compliant materials.
Engineering support for groove design and material selection.
Prototype-to-production manufacturing for specialized industries.

Eclipse Seal’s expertise ensures you get a PTFE O-ring tailored to your exact application needs.

How Eclipse Seal Supports Your PTFE Sealing Needs

PTFE O-rings offer unbeatable resistance to chemicals, heat, and wear, making them a powerful sealing option in many industries. However, their limitations in elasticity, creep resistance, and installation complexity mean they are not always the right choice for every application.

The key is understanding when PTFE is the best fit — and when alternatives like elastomers or spring-energized seals may deliver better results.

At Eclipse Seal, we help engineers and manufacturers navigate these choices by providing both off-the-shelf and custom PTFE sealing solutions. Our expertise ensures that your seals perform reliably under the toughest conditions.

Ready to find the right PTFE O-ring solution for your application? Contact Eclipse Seal today and let our team guide you to the best sealing technology for your needs.

All About Extrusion Gaps

Sat, 16 Aug 2025 22:17:00 GMT

One of the most common questions we hear at Eclipse is: How much pressure can a particular seal handle? The answer depends on several factors, but the principal limiting factor in any seal system’s pressure capacity is the extrusion gap — often referred to as the “E-Gap.”

This critical design element determines how a seal performs in high-pressure sealing applications. The extrusion gap and the desired pressure-handling capability all directly influence seal design, seal type, and material selection . Understanding what an extrusion gap is — and how to control it — is crucial for designing high-performance seals and O-rings that withstand demanding environments.

For many industries, gaining this understanding can mean the difference between long-term reliability and costly downtime, making E-Gap management not just a technical detail but a business-critical strategy.

What is an Extrusion Gap?

In sealing systems, the extrusion gap is the clearance between hardware components. In a piston configuration, it’s the clearance between the piston and bore; in a rod configuration, it’s the clearance between the rod and the housing it passes through.

The extrusion gap can be described in terms of radial clearance or diametral clearance. At Eclipse, we always state it in terms of radial clearance, which equals the diametral clearance divided by two. This distinction is important, as engineers sometimes misinterpret clearances, leading to an underestimation of the gap size.

While manufacturing specifications may call for precise tolerances, real-world conditions often create variation. For example, if a piston’s outside diameter is machined 0.030” smaller than the bore, the theoretical gap of 0.015” per side only exists if components are perfectly concentric.

Misalignment or side loading can increase the gap on one side while eliminating it on the other. In operation, dynamic forces, vibration, and wear can all influence actual clearance.

Because of these variables, seals must be designed for the maximum potential gap, not just the nominal print clearance. This ensures that extrusion gap seals perform reliably even in less-than-ideal conditions.

Why is it Called the “Extrusion Gap”?

The name comes from the most common failure mode in high-pressure systems: seal material extruding through the clearance gap. If the E-Gap is too large for the application’s pressure, the seal can deform, cold-flow into the gap, and eventually lose sealing integrity.

In practice, when too much extrusion occurs, the seal’s geometry changes permanently, and its ability to maintain a tight seal diminishes. This is particularly true for spring-energized seals , which have a weak point at the lip hinge where extrusion often begins. Simpler seal designs, such as seal rings, can tolerate more extrusion but may sacrifice wear life and long-term reliability.

In general, the smaller the extrusion gap, the higher the pressure the seal can safely withstand. That’s why controlling this clearance is one of the first design considerations for any high-pressure sealing application.

What Determines a Seal’s Extrusion Resistance?

A seal’s resistance to extrusion depends on several key factors:

1. Cross-Section Size

Larger cross-sections can handle higher pressures for the same extrusion gap. Conversely, for a given pressure, a seal with a smaller cross-section requires a smaller E-Gap to avoid extrusion.

2. Material Selection

Material choice is critical. Eclipse offers materials such as EH042 and EU000 that deliver exceptional extrusion resistance. If PTFE -based materials are required, blends with higher filler content generally improve performance. For example, PTFE blends like ET019 and EZ032 provide superior E-Gap tolerance.

3. Operating Temperature

Temperature has a significant effect on extrusion resistance. At elevated temperatures, materials soften, making them easier to extrude. A seal rated for a certain pressure at room temperature might only handle half that at 500°F. Conversely, at cryogenic temperatures, materials become stiffer and more resistant to cold flow.

4. Hardware Finish & Alignment

Surface finish, concentricity, and straightness of the mating components all influence the effective E-Gap in service. Poor alignment or rough surfaces can accelerate extrusion wear.

5. System Dynamics and Pressure Spikes

Seals in systems with frequent pressure spikes or pulsations may need more conservative E-Gap limits, as sudden surges can rapidly drive extrusion damage.

What If My Extrusion Gap is Larger Than Recommended?

In many designs, it’s not always possible to keep a minimal E-Gap. Larger hardware, tolerance stack-ups from bearings, and assembly constraints often require wider clearances.

For instance:

Large Diameter Hardware: As component sizes increase, maintaining extremely tight tolerances becomes cost-prohibitive.
Linear Bearings or Wear Rings: These often require larger hardware clearances to prevent metal-to-metal contact.
Ease of Assembly: In heavy machinery, close clearances can make installation impractical.

When minimal E-Gaps aren’t feasible, Eclipse can apply several design strategies:

Extended Heel Designs

By extending the heel of a spring-energized seal, more material must extrude before the sealing surface is compromised. Eclipse’s ECSE, EVSE, and EHSE series are examples of extended heel seal solutions.

Back-Up Rings

These are high-modulus components placed adjacent to the seal to block the extrusion gap. Materials like EP033 Virgin PEEK are commonly used, offering high strength without damaging hardware surfaces. Learn more about back-up rings .

Cammed Back-Up Rings

For extreme pressures, cammed designs expand under load to close the gap completely. This approach has allowed Eclipse seals to function in systems exceeding 30,000 psi.

Dual-Seal Configurations

In some cases, using two seals in tandem — one to take the brunt of the extrusion risk and another as a primary sealing element — can be an effective solution for oversized E-Gaps.

Related Case Study

For a real-world example of how Eclipse engineers address the challenges of balancing extrusion gap requirements with other hardware constraints, read our case study: Balancing Extrusion Gap and Wear Ring Exposure in a High-Pressure CO₂ Extraction Application . This project highlights the trade-offs, custom design considerations, and performance results achieved when working within demanding operating conditions.

Measuring and Maintaining an Extrusion Gap

Accurate measurement and ongoing monitoring are essential for maximizing seal life. Precision metrology tools can confirm radial clearances during assembly. Over time, wear or deformation of hardware can enlarge the gap, making scheduled inspections critical.

Maintenance best practices include:

Measuring clearances during every major overhaul.
Inspecting seals for early signs of extrusion damage.
Replacing worn hardware to restore original tolerances.
Documenting measurements and comparing them againstmanufacturer recommendations to track gradual changes.
Conducting finite element analysis (FEA) simulations for new designs to predict extrusion risk.

Industry Applications Where Extrusion Gap Control is Critical

Extrusion gap considerations apply to nearly all high-pressure sealing systems, but they are especially critical in:

Oil & Gas Sealing Solutions : Downhole tools must endure extreme temperatures and pressures.
Aerospace : Hydraulic actuators demand leak-free operation despite fluctuating loads.
Medical Devices++ : Surgical and diagnostic instruments rely on precision sealing.
Marine & Subsea: Saltwater corrosion and deep-sea pressures present unique sealing challenges.
Industrial Equipment : Heavy-duty presses and hydraulic systems require robust sealing against pressure spikes.
Renewable Energy Systems : Wind turbines and hydroelectric systems often operate in remote, harsh environments where seal failure is costly.

By tailoring seals to these industry-specific challenges, manufacturers can dramatically improve service life, reduce downtime, and ensure compliance with performance standards.

Designing for Performance and Reliability

Controlling the extrusion gap is more than a design choice — it’s the foundation of seal and O-ring performance in high-pressure environments. By selecting the right materials, optimizing hardware tolerances, and incorporating advanced design features like extended heels and back-up rings, engineers can significantly extend seal reliability and service life.

At Eclipse, we specialize in custom high-performance seals for the most demanding applications. Whether your project involves aerospace, oil and gas, medical, or marine systems, our engineering team can design a solution that maximizes performance and durability.

Contact us today to discuss your unique sealing challenges and discover how we can engineer the ideal solution for your needs.

Case Study: Spring Energized Seals in Autonomous Underwater Vehicles

doug@eclipseseal.com (Doug Montgomery) — Tue, 22 Jul 2025 01:45:35 GMT

Much like aerial drones and unmanned aircraft, submarines and underwater vehicles have advanced similarly in recent years. Improvements in lithium battery capacity and efficiency have led to the increased usefulness of unmanned undersea vehicles by extending their range and operating time. Size and weight of the overall vehicles have been significantly reduced. Often, fully instrumented submersible vehicles can be small enough to be lifted and handled by a single person, drastically reducing operating costs by eliminating the need for large deployment ships or launching cranes.

Advancements in software and sensor development have also led to an increased number of autonomous vehicles employed in the field. Autonomous Underwater Vehicles (AUV) have distinct advantages over similar remotely operated vessels. With the ability to operate independently, AUV’s eliminate the need for any kind of hardline tether or direct communication with a pilot on the deployment vessel. This greatly extends their range and reduces operating costs.

AUV’s have seen growth in usage across a wide variety of industries due to these recent advancements. Commercially, the oil and gas industry has made extensive use of AUV’s in seafloor surveying. Properly mapped areas not only detail new potential off-shore drilling sites but can also help identify efficient routing of pipelines and other infrastructure, both reducing costs and environmental impact.

Existing pipeline inspection is also more frequently being performed by AUV’s. The increased regularity and thoroughness of inspections help ensure issues are identified early, reducing risk and worst case, preventing a major environmental disaster.

Scientists have also employed AUV’s for use in several oceanographic research functions ranging from microbial life surveyance to ocean temperature monitoring. AUV’s also find extensive use in military applications such as intelligence/reconnaissance, as well as underwater wreckage location and recovery.

With more AUV’s in service and their capabilities increasing, the demand for better sealing performance is also intensifying. Eclipse is there to meet the demand as seals play an obvious critical role in a submersible vehicle.

The Client’s Issue

Eclipse was approached by a leading AUV manufacturer looking for a better seal to be used on the vehicle control fins. Located at the rear of the vehicle near the thrust propeller, two sets of fins pivot to control the up and down, and side-to-side direction of the vehicle. They are actuated by electric servo motors. Repeatable and consistent functionality of the fins is critical for precise control of the vehicle. A UAV may be used to survey a large portion of the seafloor where it is required to maneuver in a specific pattern. This is to completely cover a geological grid of interest. Without accurate steering capability, the AUV’s usefulness will be limited.

The customer was looking to extend the depth capability of their current AUV. With increased depths comes increased external pressure, and this is an obvious concern for the sealing systems. More specifically, how the pressure affects the friction of the seals. All seals will be pressure energized to a degree, and many common seals are specifically designed to allow the external pressure to help provide sealing force and energy.

While increased sealing force is great for providing leak-free seals, it comes with the adverse effect of increased friction at the interface surface. This is exactly what the customer was experiencing with their current sealing configuration. Due to the increased water pressure, at a certain depth, the friction around the shaft of the control fin was great enough that the servo motors were unable to pivot the fin. The AUV would effectively be out of control.

To go to extreme depths, some vehicles use a pressure-balanced system. This is where the internal pressure of the vehicle, often filled with oil, is made to be similar to the external water pressure. Thus, the pressure differential across the seals is very small. While an effective solution, it is also costly. The customer did not want to change their internal components, so this was not a viable option.

Increasing the size or torque capacity of the fin servo motors was also not an option. With power and space being in limited supply on a submersible, the customer could not afford any additional power consumption for increased torque to counteract the friction. Eclipse was challenged with creating a leak-free seal that also met the customer's stringent friction and torque requirements.

Operating Conditions:

Pressure: 400 PSI

Media: Seawater

Temperature: 32° to 120°F

Shaft Diameter: 0.375”

Dynamics: Slow Rotary, Oscillating

Breakout Torque Requirement: less than 4 in-lbs

The Eclipse Solution

Eclipse knew seal material selection would be the first major area to address. When friction is of chief concern, a PTFE-based seal material would seem like a good choice. Eclipse knew from experience, though, that a PTFE material would likely not meet the near-zero leakage requirement for sealing water on a relatively rough shaft surface finish. On the other end of the spectrum, a softer urethane material would no doubt seal very well, but the coefficient of friction would be too high.

Eclipse chose its EH042: Thermoplastic Elastomer as the seal material. Thermoplastic Elastomer (TPE) has a coefficient of friction halfway between a typical PTFE and Rubber or Urethane. Therefore, it inherits the high sealability of the softer compounds without being too high in friction. Eclipse knew this would be the perfect seal material choice for tightly controlling water while keeping torque requirements to a minimum.

Unlike many rubber compounds, EH042 also has the bonus of not being susceptible to explosive decompression. In underwater applications, this provides an added level of reassurance that sealing integrity will be maintained even in emergency surfacing situations.

While the seal material alone would have been a significant upgrade to the customer’s current seal, the improved properties of the EH042 would not be enough to meet the very low torque requirement. Eclipse turned to the physical design of the seal itself. In rotary situations where torque is very sensitive, a Canted Coil Spring Energized Seal is likely the best choice.

The unique properties of the Canted Coil spring lend themselves to very precise friction control. Unlike Cantilever spring or O-Ring energizers, which exhibit a largely linear load versus deflection relationship, Canted Coil has the characteristic of a near-constant load over a wide deflection range. This means that as the spring becomes more compressed, the load also does not increase. This distinctive property is very useful in seals where friction due to loading needs to be finely tuned, as the seal can be designed to work in the constant loading range.

Eclipse chose Hastelloy® as the spring material for its in-house manufactured canted coil spring. As an upgrade to the standard 300 series stainless steel spring, Hastelloy will provide better long-term corrosion resistance in the saltwater environment.

But even with the use of the EH042 material and canted coil spring, a standard type spring energized still would not have met the customers’ torque requirement. Eclipse turned its attention to the actual seal geometry to look for further improvements in the frictional loading. Despite having a relatively large hardware envelope to fit the seal, Eclipse chose to use one of its smaller spring series to limit the size and depth of the spring cavity within the seal. Having a smaller area to act upon, the pressure energization by the outside water would therefore be limited. A smaller series spring, of course, has a smaller available deflection range to operate in, but Eclipse worked within this limitation by utilizing the careful tolerance control within its in-house machining capability.

The lip geometry of the seal and how it interacts with the shaft mating surface was the next area of focus. By modifying the machined angles of the lip, Eclipse precisely controlled the amount of surface contact between the lip and shaft. This delicate adjustment led to the perfect balance of limiting contact area, therefore decreasing friction, and still providing enough surface engagement for proper sealability.

How it Performed

Eclipse’s EH042 Canted Coil Spring Energized proved to perform perfectly in testing and moved on to be the standard seal for the production AUV units. Eclipse worked very closely with the customer in the testing phasing providing numerous seal torque estimates at different sea depths. All estimates were verified by the customer in real world testing. The seal delivered outstanding sealability while at the same time meeting their very low torque and friction requirements.

The allowed the customers AUV to achieve greater depths without any modification to the fin drive motors or resorting to a pressure balanced system. This gave the customer a significant advantage over its AUV competitors. It allowed them to secure a larger portion of the marker and increase sales. Not to mention improving the capability of AUV to survey greater depths and gather valuable research information.

Contact Eclipse today if your application might benefit from an engineered solution utilizing Eclipse’s decades of seal experience and in-house machining expertise.

Canted Coil, Cantilever, or Helical: Which Spring Type is Right for My Application?

doug@eclipseseal.com (Doug Montgomery) — Tue, 24 Jun 2025 02:19:02 GMT

Aside from ball valve seats or non-contact labyrinth seals, PTFE is rarely used without a secondary energizer. This is due to PTFE’s inelastic nature. Unlike urethanes or elastomers which possess an inherent springiness, PTFE is often considered an “unalive” material. Much like a lump of clay, it will not bounce back once deformed.

Especially in dynamic applications, this is not a desirable quality. Fortunately, with the addition of a spring or elastomer energizer, all of PTFE’s excellent attributes can be fully exploited in terms of sealing.

Much like the rest of the seal industry, Eclipse utilizes three metallic spring energizer types for the seals we manufacture. Canted Coil, Cantilever V-Spring, and Helical. While each spring type ultimately accomplishes the same task, energizing a PTFE or polymer seal jacket, we’ll see that each type has unique properties better suited to certain applications.

Figure 1 below shows generalized load versus deflection curves for the three spring types. As you can see, each one is quite a bit different, favoring distinct circumstances and applications. Though, we’ll also find out load curves are not only deciding factor when choosing a spring.

Canted Coil

Canted Coil spring is similar to a standard round wire coil spring except the coils are canted at angle to one side. The spring takes on an oval, or elliptical shape with a minor and major axis. If formed into a circle, as in a rod or piston seal jacket, the canted coils allow the spring to be compressed on the minor axis in the radial direction.

Eclipse manufactures its own canted coil spring in the standard seal series cross-sectional sizes. Eclipse cuts to length and laser welds all of its canted coil spring in house, ensuring the best quality control and customization possible.

Canted Coil’s claim to fame is its very unique load curve. As shown in Figure 1, there is a large portion of its deflection range where the spring load remains nearly constant. This is in contrast to the other spring types which exhibit linear load curves where more deflection equals more load.

Canted Coil spring seals are designed to work in this constant load range providing the seal with stable, predictable spring force throughout the course of its wear-life. Unlike other spring types with linear load curves, spring force will not be reduced as the seal wears.

This is a distinction among the spring types, as cantilever and helical spring can be destructively yielded if over compressed. In applications where there is potential for the seal to see a back-pressure situation, canted coil might be the best choice. A canted coil seal will likely return to operational despite seeing significant pressure in the opposing direction. Cantilever and helical spring have the potential to yield resulting in a failed seal.

Canted coil’s robustness can also be an advantage in complex gland configurations where seal installation is not straight-forward. Though it typically is not recommended, it is possible to install a canted coil seal into a solid gland if the diameter is large enough compared to the cross-section. Solid gland installation is never advised with the other spring types due to the possibility of damage.

Canted coil is also the spring of choice for very small seal applications. Eclipse has made canted coil seals with ID’s as small as 1mm. V-Spring and helical have physical limitations on inner diameters.

Cantilever V-Spring

V-Spring is made from thin strips of sheet metal—typically 301 stainless steel—formed into a V shape. Alternating relief cuts along the V allow it to be bent into a circular form. This design functions like a leaf spring within the seal jacket, which is why it's often referred to as a Cantilever V-Spring .

The spring’s energy and load are concentrated at the tips of the V, aligning with the seal jacket’s geometry to create a focused point-load at the seal’s leading edge. This makes it particularly effective in reciprocating applications where both sealing and media exclusion or scraping are required.

When paired with a highly wear-resistant material like UHMW-PE, the V-Spring becomes a powerful sealing solution for thick, viscous substances such as adhesives and epoxy resins. To enhance performance, multiple V-Springs can be stacked or nested within the seal jacket, increasing the spring load and providing redundant sealing contact points.

In addition to its performance benefits, the V-Spring is often selected for its cost-effectiveness, particularly in high-volume production. It is manufactured using progressive dies and punches, making it the most economical spring to produce in long spools. It can be easily cut to length and welded into a circle using simple resistance welding techniques. Eclipse fully welds each spring to ensure uniform load distribution, though it can function in a seal jacket unwelded.

For very high-volume applications with small diameters, a circular spring pattern can be etched directly into sheet metal and then formed into a V shape. This eliminates the need for cutting and welding, further reducing costs.

However, the V-Spring’s concentrated point-loading, while advantageous in some scenarios, can be a drawback in rotary applications where it may accelerate wear on both the seal and hardware. Its linear load curve means that spring force decreases as the seal wears, potentially leading to overloading at the start and underloading toward the end of the seal’s life.

Another limitation of the V-Spring is its susceptibility to permanent deformation if over-compressed or distorted, which can render it ineffective. This is a concern in high back-pressure environments, such as down-hole drilling, where unexpected pressure spikes can flatten the spring.

Lastly, V-Springs have limitations at smaller diameters. As the diameter decreases, the inner tabs of the V can overlap and crowd the inner circumference, restricting their use in compact designs—an area where Canted Coil and Helical springs perform better.

Helica l

Helical Spring was actually the first spring type to be developed in the history of spring energized seals . It consists of a thin ribbon of sheet metal curled into a tight spiral to form a flexible tube. Helical spring is typically 17-7 Stainless steel whereas the other spring types are usually 300 series stainless steel.

As shown in Figure 1, helical has a very steep, linear load curve. It has the highest loading of all the spring types, but also the smallest deflection range. The high load can be an advantage in specific applications.

Helical is most often used in static face seal applications. Especially in cold temperatures and cryogenics. This is where the high loading helps ensure the seal is in contact with the faces of the hardware despite shrinkage of both the seal and hardware and stiffening of the jacket material.

Helical is the most delicate of all the spring types, it is easy to yield if improperly handled or over compressed. This combined with its small deflection range means it is almost never used in dynamic applications. It is also not recommended for applications with frequent pressure cycling or situations where the seal needs to be uninstalled and reinstalled in the hardware multiple times. In this sense, helical spring seals can almost be thought as “crush gaskets."

If there is room in the hardware, nested cantilever V-springs can provide similar loading as helical springs but with a wider deflection range and added resilience against yielding.

Conclusion

So what spring is right for your application? If you want a short and sweet general answer: Rotary, use Canted Coil. Reciprocating, use Cantilever V-Spring. Static Cryogenics, use Helical. Of course, as we see above there are many aspects to consider and one solution will not always be the best choice.

The good news is that Eclipse is here to help. With decades of experience using every spring type in thousands of different applications, Eclipse is here to help specify the best spring for your unique application.

Case Study: Polymer Superfinishing for Optimal Cryogenic Gas Sealing

doug@eclipseseal.com (Doug Montgomery) — Wed, 28 May 2025 01:38:12 GMT

Over the years, Eclipse has designed and manufactured sealing solutions for media ranging from mud to processed cheese to chemicals with names no one can pronounce and most everything in between.

By far, one of the most challenging media to seal is the first element on the periodic table, Hydrogen. Its extremely small molecule size and the fact that sealing needs to be done at cryogenic temperature present difficulties for all seal designs and materials.

While Eclipse’s Spring Energized Seals regularly perform under these operating conditions, the extremely stringent leakage requirement needed by the customer presented Eclipse with a unique challenge. Normally, such tight leakage constraints are achieved with the use of very soft and compliant seal materials such as specialized O-Rings or Thermoplastic Elastomers.

But the extreme temperature range and friction requirements of the valve meant that the use of soft, highly sealable materials would not be possible.

Polymer Superfinishing

Eclipse knew that the application parameters meant the use of a PTFE based seal material would be required. Eclipse also knew that a typical, standard PTFE spring energized seal would not meet the customer’s leakage requirement. Eclipse turned their attention to surface interaction between the seal lip and hardware surface. If the seal lip and hardware surface finish could be optimized to exceedingly high levels then the permeability of the Hydrogen between the mating interfaces could be greatly reduced.

Superfinishing has been a technique used on metals for many years, but methods used for metals don’t typically translate or work well for polymers. Eclipse’s in-house manufacturing and design team developed both special tooling and techniques to provide a similar superfinish on PTFE based seal materials.

Eclipse’s many years’ worth of PTFE machining experience was key in developing and making this technique production ready.

Optimizing PTFE Machining with Eclipse’s EZ030 Technology

It might be easy to think that machining plastic would be less difficult than steel or metallic materials, but anyone who has tried probably quickly found out it’s not the case. Eclipse grinds much of its own tooling and utilizes cutting inserts out of high-speed steel, carbide, and diamond.

Eclipse developed special large-radius tooling to aid in the finishing. From there, “speeds and feeds” were adjusted in the CNC until the best finish was possible was achieved. While taking more time than standard machining techniques, the gains in the end were well worth it.

To further improve sealability performance, Eclipse used its EZ030 modified PTFE. EZ030 is the unfilled variant of our enhanced PTFE. It retains all the advantages of standard PTFE, including chemical compatibility, friction properties, and temperature range. The key benefit of this modified version is its improved material adhesion during processing, which leads to a denser final structure. This denser structure enables EZ030 to achieve superior machined finishes on seals and offers enhanced permeation resistance. Consequently, it provides an unparalleled seal for use in gaseous media such as oxygen, hydrogen, nitrogen, and natural gas.

Eclipse’s effort in developing the superfinish technique, combined with the excellent properties of EZ030, resulted in a seal that met both the customer’s tough leakage requirement and life cycle targets.

If you have an application that can benefit from Eclipse’s superfinishing technique, please contact us today.

Case Study: Balancing Extrusion Gap and Wear Ring Exposure in a High-Pressure CO2 Extraction Application

doug@eclipseseal.com (Doug Montgomery) — Thu, 17 Apr 2025 07:25:07 GMT

Often, seal designers can seem like they’re caught in constant struggle to balance the demands of sealing application with the reality of physical and material constraints. It is the job of the engineers at Eclipse to understand and weigh these limitations with the goals of the application.

For example, when a customer needs an extremely low friction seal yet very high sealability, there is always a compromise that needs to happen. The magic seal material that has the pliability and excellent seal characteristics of rubber and the low friction, high wear resistance and temperature range of PTFE, simply doesn’t exist.

Another frequent scenario is when the customer needs a seal to accommodate loose or poor hardware tolerances yet has a very small physical envelope to incorporate a seal. The smaller the seal, the smaller the effective deflection range due to the physical limits or an O-Ring or spring. While the application might need cover the range of a 400 series spring or O-Ring, there might only be room for a seal the size of a zero series, which obviously presents a problem.

Similarly, a customer might have the desire for a seal with very long wear life, yet the hardware assembly may be severely limiting in the area meant for the seal. Eclipse has been presented numerous applications where a space for a seal was never even considered in the original design. Without a properly sized seal, wear life has the potential to be restricted simply due to the fact there is less seal material available to be worn away before structural integrity and therefore sealability is compromised.

Another very common problem in sealing applications where bearings are needed, is the balance between the having enough exposure for the wear rings without also causing too large of an extrusion gap to create complications for the seal.

Eclipse was approached by a customer facing this very issue in their high-pressure, supercritical CO2 extraction equipment. Eclipse’s decades of experience meant they came to the right place for the optimal sealing solution.

The Client's Issue

With the growing popularity of Cannabis derived products such as CBD oil, the processes for extraction have come under examination for increased productivity and durability. A customer came to Eclipse looking to redesign the piston seals used in their CO2 SFE extraction equipment.

The customer was looking for improved wear life and longevity of the seals, as well as, improved lead-time and availability of the seals once they needed to be replaced. The customer’s increased production volumes and run-rates where quickly wearing out the OEM seals and they were unhappy with the lead-time and service of the original seal supplier.

With some of the best lead-times in the industry for custom PTFE seals, Eclipse knew it could deliver if an improved seal design could be implemented.

Operating Conditions: 

Reciprocating Piston Seal
Bore Diameter: Ø3.250”
Stroke: 6”
Cycle Rate: 35 cycles per minute
Media: CO2
Pressure: 800 – 5,000 PSI
Temperature: 65° to 175°F

The customer was willing to redesign the piston seal gland configuration, but the overall length of the piston could not be changed to ensure correct functionality in the original equipment. With significant side-loading of the piston present, wear rings would be necessary for proper piston guidance and to safeguard against any potential metal-to-metal contact between the piston and bore.

If metal-to-metal contact did occur and the bore was scratched or galled, the customer would face extensive down-time while they wait for a replacement part. This would cost them a significant amount of money from lost productivity, not to mention the cost of the replacement bore. To mitigate this potential risk, the customer was unwilling to eliminate wear rings or reduce their width, thus Eclipse was faced with a design constraint with the amount axial space available on the piston for the seal.

This space constraint presented a challenge because with the importance of proper wear ring exposure in the system, the extrusion gap therefore needed to be sizable. With limited space to either substantially extend the heel of the seal, or incorporate a back-up ring, Eclipse would need to utilize some special design techniques and features to present a high wear life seal.

The Eclipse Solution

Balancing extrusion gap and wear ring exposure is very typical problem in the seal industry. In systems where operating pressures are relatively low this might not be a problem, but when pressures increase seal integrity can quickly become compromised.

In a piston application, wear-ring exposure and seal extrusion gap become the same entity. In most cases, once tolerance stack-ups are performed with both the bearing and hardware dimensions, the resulting necessary exposure dimension will be far beyond the typical maximum extrusion gap recommendation for the seal.

Not given enough exposure on the piston, the wear ring has the potential to be loose in the groove making it ineffective as a bearing. This would place undue side loading on the seal leading to premature failure and/or the piston contacting the bore. In almost every case, this metal-to-metal contact will likely gall or score the bore enough to destroy a proper sealing surface finish, if not more extensive damage.

On the other hand, if the extrusion gap for the seal resulting from the needed bearing exposure is too large, the seal will eventually be pushed into the gap by the pressure and ultimately cause a failure. The higher the pressure of a system, the smaller a recommended extrusion gap will be. Without any other considerations, extrusion gaps are typically suggested to be made as small as possible. This fact is obviously diametrically opposed to the need for bearing exposure.

To combat large extrusion gaps, spring energized seals (as in this case) can be made with an extended heel design. This physically puts more sealing material behind the seal that can be deformed into the gap without affecting the critical area of the seal. The other common solution is to incorporate a back-up ring behind the seal. A back-up ring can be designed to basically reduce the size of the extrusion gap the seal is exposed to.

However, both of these solutions would require additional axial space on the piston, which Eclipse did not have the luxury of working with. Eclipse started by using a smaller spring series than the hardware cross-section would typically call for. The smaller spring would effectively allow the heel of the seal to be extended, aiding in the extrusion resistance of the seal. This also means the sealing lips would be thicker than normal.

Eclipse utilized this extra material in the lips to modify the seal geometry to further fortify against high pressure failure. The ultimate failure mode of a spring energized seal due to extrusion is usually when deformation of seal reaches the hinge point of the spring cavity. To guard against this, Eclipse offset the location of the spring groove to thicken this vulnerable hinge point.

Eclipse chose its ET040: Polyimide/MoS2 filled PTFE for the spring energized seal jacket. While not the most extrusion resistant material Eclipse has to offer, the customer’s stainless-steel bore material was limiting on how aggressive the seal material could be. ET040 would provide a good level of toughness without wearing the bore. The added internal lubricity reduces friction and the fine particle size of the Polyimide improves sealability while sealing gases such as CO2.

Eclipse chose its ET010: Bronze filled PTFE for the wear rings. This industry standard bearing material would fit well within the design objectives of the project.

How It Performed

With Eclipse’s revised seal and piston design, the customer saw increases in seal life and reliability. This allowed them to run their production processes for longer intervals between scheduled maintenance. The reduced down-time increased plant productivity positively affected the customer’s bottom-line and allowed them stay on top of shipments of their high demand product.

The customer was also very pleased with Eclipse’s comparatively short lead-time and reliable delivery on replacement seals. Their moderate investment in redesigning their piston configuration to use Eclipse seals proved to be profitable choice.

Contact Eclipse today if your sealing application could potentially benefit from Eclipse’s custom designed and manufactured seals.

Case Study: The Manufacturing Challenges of Tiny Spring Energized Seals

doug@eclipseseal.com (Doug Montgomery) — Fri, 21 Mar 2025 01:56:18 GMT

Eclipse is challenged daily by applications pushing the limits of seal design and integrity. Whether it be ultra-high pressure, excessive surface speed, or extended wear-life (or all the above), the pursuit of better sealing performance never ceases.

But Eclipse also is frequently presented with applications challenging not because of their extreme operating conditions, but rather the physical size of the seal and hardware envelop. Eclipse has in-house capabilities to manufacture seals up to 55 inches in diameter, and over 100 inches through production partners.

While seals with huge diameters certainly grant their own significant levels of intricacy, here we’ll look at the other end of the spectrum – the micro-sized seals. And not only a simple seal ring, an inherently more complicated and geometrically detailed spring energized seal. As we’ll see, very small diameters make multiple manufacturing aspects more involved and challenging.

The Client's Issue

Eclipse was approached by a customer looking for a sealing solution in their epoxy dispensing equipment. They needed an effective seal for the reciprocating rod responsible for the flow-control and metering of the epoxy while being dispensed.

Operating Conditions: 

Reciprocating Rod Seal
Epoxy Dispensing Head
Rod Diameter: 1.2mm [0.047”]
Stroke Length: 6mm [0.236”]
Cycle Rate: 15 per min
Media: Epoxy
Operating Pressure: 1,500 PSI
Temperature: 70° to 150°F

Sealing Epoxy has its own set of difficulties, but Eclipse supplies numerous successful sealing solutions to applications such as this across the industry. A set of design and manufacturing principles has emerged from Eclipse’s years of experience developing seals for thick and viscous media.

In general terms, most viscous media sealing solutions have three things in common: A variant of UHMW for the seal jacket, heavy spring loading, and multiple point contacts with increased interference. In most cases, multiple nested V-Springs are incorporated to provide optimal load and energize the compound contact points on the seal.

With this formula, Eclipse has had great success sealing media like epoxy, urethane, silicones and acrylics. The heavy loading is necessary to effectively wipe the reciprocating rod. This is balanced with the correct material and design geometry to also provide long wear life of the seal, which has the potential to be compromised under such loading.

Eclipse’s challenge in this case was to incorporate these same proven principles in a micro-sized seal.

The Eclipse Solution

Eclipse knew immediately that the size limitations would not allow the typical viscous media design elements to be employed, and therefore different methods would need to be used to accomplish the same tasks.

Starting with the spring, it was easily apparent that cantilever V-Spring would not be an option. At this pin-like diameter, the tabs of even zero series spring would be overlapping on the inner diameter once the spring was wrapped into a circle.

A way to avoid this would be to have a specialty die made to stamp and form the V-Spring. The inner diameter tabs could then be tapered to avoid overlapping. But at the modest quantities the customer was requesting for the seals, the very expensive die tooling would not make financial sense.

Eclipse knew they would need to use Canted Coil spring . Canted Coil would not have the same problem as V-Spring, it could be welded to the right diameter without issue. But at this size, cutting and welding would be easier said than done.

Thankfully, Eclipse’s skilled and experienced spring personal were up for the challenge. With a spring cut length of only about 0.300 inches, delicate handling and precision attention to detail would be necessary. The fine motor-skills of Eclipse’s operators made short-work of the tiny spring.

In 2019, Eclipse made a key investment in a new piece of equipment designed to aid in spring operations such as this – A Laser Welder. Equipped with a built-in microscope, welding becomes the very simple operation of lining up the weld location with the scope crosshairs and pressing a foot pedal. The precision power and duration control of the laser strength allows minuscule welds to be placed with exacting accuracy. Today, Eclipse has multiple Laser Welders to keep up with production demand.

Turning to the design of the seal jacket, Eclipse was again challenged with inherent difficulties manufacturing a seal at this minute diameter. The seal inner diameter would not allow the machining of a typical seal contour, it is simply too small to fit any kind of profiling tool inside. The ID would have to be drilled straight through.

While this sounds like a straight forward procedure, this presents some major problems with the seal design. With no way to make clearance for the heel, or solid portion of the seal, shaft interference would have to be carefully controlled. Too much interference would make the shaft very difficult to install, while too little would not provide adequate media scraping and reduced service life.

But because the inner diameter needed to be drilled, the dimension would be dictated by the size of the drill bit. However, due to the nature of the seal material, the resulting hole size could either shrink or grow after cutting.

Eclipse chose its EU040: Premium Grade UHMW which would provide long wear life and very effective scraping of the viscous media. But a drilled hole in UHMW would most definitely not match the size of the drill bit.

In this case, only one or two thousandths of an inch could make the difference between a successfully functioning seal and one with severe installation problems. Eclipse’s skilled machinists with decades of combined experience proved to be invaluable as the correct size drill was chosen to allow the perfect amount of installation interference for the seal.

Without the ability to design in multiple sealing points on the jacket combined with nested V-Springs, Eclipse needed to maximize the scraping potential of the canted coil spring. This was accomplished by cutting back the inner diameter sealing lip to therefore locate the primary contact point directly below the most focused part of the spring load.

With the spring and seal jacket complete, assembling the two components would be the last step of production. Canted coil springs are typically very easy to install in seal jackets. Most of the time, larger spring series at reasonable diameters are simply installed by hand.

But a spring this small going into a relatively high durometer UHMW jacket, would not be able to be hand installed without risk of damage or incorrect orientation. Eclipse has a well-established solution to these scenarios. With the aid of a custom machined tool set, spring installation becomes a straight-forward procedure. The set includes three pieces, a cone shape for the ID and funnel shape for the OD of the seal, plus a pusher tool. The spring is fully guided and compressed into its correct orientation as it is pushed into the seal groove.

How It Performed

Sealing Epoxy and other very thick and viscous media presents unique challenges in the sealing world. Eclipse’s years of experience and development have yielded a successful formula for seal design in these situations.

Unfortunately, at the very small diameter the customer was requesting in this case, the typical design elements could not be incorporated. Eclipse found alternate ways to achieve the same goals while overcoming the innate manufacturing challenges that were posed.

Eclipse’s solution proved to effectively scrape the heavy epoxy media, successfully containing it from entering parts of the dispensing head that could cause functionality problems. The design also proved to wear resistant enough that the service intervals of the equipment did not need to be shortened.

The customer was very satisfied with the overall sealing performance and after years of successful employment in the field, Eclipse has a well-known and substantiated design standard for future products.

Contact Eclipse today for a sealing solution for your viscous media application. Whether it be one millimeter in diameter or one meter and beyond.

Case Study: Angled Spring Grooves for Custom Spring Energized Ball Seats

doug@eclipseseal.com (Doug Montgomery) — Thu, 13 Feb 2025 22:04:02 GMT

A Ball Valve is a simple and robust valve used in applications and industries across the spectrum. It consists of a ball with a hole through the center that can be rotated 90°. The hole is either aligned with flow and thus open, or perpendicular to flow and therefore closed. The straightforward quarter-turn action is fast and simple to operate, and the position of the handle provides a clear indicator of whether the valve is open or closed.

Most typically used as a shut-off valve, many households likely use ball valves at some point in the water supply plumbing. Not relegated to common plumbing, many industries use ball valves for critical control applications including aerospace and cryogenics. Their reliable operation and high-pressure handling ability make them an attractive solution for many specialty operations.

The seals inside the ball valve obviously play an important role in their performance and reliability. There are two main seals in a common ball valve, they are referred to as seats. The seats are typically machined or molded to match the diameter of the ball and are mechanically compressed against the ball face. Seat material varies by application needs, but Virgin PTFE is frequently used.

Eclipse was approached by a customer looking for a very specialized ball seat. They wanted to utilize a spring energizer in the seat. While easy to suggest, this would create a significant challenge in the manufacturing of the seal. Eclipse, nevertheless, would be up for the intrepid endeavor.

The Client's Issue

Eclipse’s customer was looking for a sealing solution for a ball valve in their industrial gas processing plant. The ball valve would serve as a critical shut-off point in the system. The valve would be actuated by an electric motor and therefore could be operated remotely.

The customer was looking for an improvement in the overall wear life of the ball seats, while at the same time, providing consistent and predictable actuation torque. Being motor activated, the torque required to move the ball open or closed was limited. Therefore, the friction generated by the ball seats would need to be carefully controlled.

Operating Conditions: 

Ball Valve Seat
Ball Diameter: Ø2.500”
Media: Petroleum Processing Gases
Pressure: 100 PSI
Temperature: -40° to 175°F

The Eclipse Solution

The typical PTFE ball seat can provide many years of service over many cycles and still retain positive sealing. Over time, unenergized PTFE will wear and leakage will eventually occur. While there are valve designs that incorporate external springs to energize the seats, the customer was looking to retain a simple hardware design without adding mechanical components and increasing the physical size of the valve.

Eclipse knew a spring energized seal would be the answer. Eclipse designs and manufactures thousands of spring energized seals every year, all which provide the sealing characteristics the customer was desiring here. The concept, design, and functionality would certainly be nothing uncommon to Eclipse, but the packaging within the constraints of a typical ball seat would provide the challenge.

In order for the spring to function properly, as in a regular radial seal, the spring would need to be oriented at an angle that would match the contour of the ball. While contact could be made with the ball using a standard face or radial spring orientation, the effectiveness of the spring would be greatly reduced since the compressive force would not be acting in the correct direction. Consequently, deflection range and therefore wear life would be compromised.

For the spring seal to function at its full potential, the angle at which its containment groove is machined within the seal would need to match the angle of incident of the ball. This presented a manufacturing challenge as the necessary angle would certainly be non-standard to any available lathe tooling.

Eclipse designs and many times fabricates all the necessary lathe tooling in-house. Grinding and sharpening tools is a normal and frequent operation performed by Eclipse’s skilled machinists. This allows Eclipse to frequently machine complex or custom shapes and spring grooves. But in this case, the angle at which the spring groove tool would need to be made would be impossible to produce with conventional tool grinding equipment.

In such instances, Eclipse turns to EDM (Electrical Discharge Machining). EDM allows geometries that normal would be impossible to grind such as nearly sharp inside corners and back angles. Eclipse’s environment of an integrated relationship between its production and engineering staff allowed the necessary CAD model files to be designed to facilitate the production of the EDM tools.

The final step would be to fabricate a custom tool holder to mount the EDM tool. With that, the necessary steps to machine a spring groove at the unusual ball angle would be complete. A simple seal design concept can take the efforts of multiple engineers, machinists, and manufacturing techniques to achieve. Eclipse thrives in these situations and prides itself in its innovative manufacturing methods and solutions.

Turning back to the seal design, Eclipse chose it’s EZ038: Graphite filled Modified PTFE as seal material. The benefits of Modified PTFE would greatly be utilized in this application. It’s improved resistance to cold-flow compared to conventional PTFE would help ensure long life. It’s superior permeability resistance and the ability to achieve an excellent seal surface finish combined with the graphite filler, make it ideal for critical gas sealing.

How it Performed

The advantages and benefits of spring energized PTFE seals are realized everyday in applications across the world. These are usually limited to either rod or piston seal configurations. Adapting this design to work in a ball seat arrangement presented some unique manufacturing challenges. Eclipse’s team of experienced engineers and machinists welcomed the opportunity and successfully designed and fabricated the necessary tooling.

The spring energized ball seat was able to extend the wear life and service interval of the valve. The spring is able to keep constant energy on the sealing lip contacting the ball, even as the lip wears. While extending the life of the seal, the spring energizer also facilitates predictable and consistent actuation torque by carefully controlling seal friction. The customer was ensured the remote motor actuation would always function as intended.

The customer was very pleased with Eclipses custom design, engineered and manufactured ball valve seat. Contact Eclipse today with your challenging sealing application.

Case Study: Dual Lip Crimped Case Seal in High Speed Rotary Vacuum Application

doug@eclipseseal.com (Doug Montgomery) — Fri, 17 Jan 2025 12:26:24 GMT

Eclipse deals regularly with challenging sealing applications from all industries. High pressures and speeds create unique sets of conditions where seal design and material properties are pushed to the limit. While reciprocating applications can certainly test seals to the edge of capability, often times rotary applications can present the greatest challenge to seal integrity and wear life.

Unlike reciprocating configurations where the seal is acting on a different part of the shaft or bore throughout it’s operating range, rotary seals must operate on the same sealing area continuously. This makes things like heat rejection much more difficult, especially in unlubricated or dry running applications. Extreme localized heating can have negative affect on both seal and hardware life.

Rotary applications also pose sealing difficulties due to the simple fact that surface speeds can be much higher than in reciprocating systems. A simple electric motor can operate at very high rpm, while long stroke, high speed reciprocating machinery is a major piece of equipment that is far less common (though Eclipse also has sealing solutions in a number of these situations).

A customer approached Eclipse with an application that was beyond the scope and capability of any standard, off-the-shelf rotary seal . This sealing system would require a combination of both wear resistance in high-speed rotary, as well as excellent leakage control and sealability. Two factors that, more often than not, work in opposition to each other.

The Customer Issue

The customer was developing a test system that required an electric motor shaft passed through the wall of a large vacuum chamber. The testing apparatus needed a sizable motor to meet the speed and torque requirements. Adapting the motor to operate inside the chamber would not be practical due to contamination and motor cooling concerns. Therefore, the motor would have to be placed outside the chamber and a driveshaft would have to go through the chamber wall. Which, of course, would need a seal.

Operating Conditions: 
Rotary Shaft Seal 
Shaft Diameter: 2.5” 
RPM: 7,500 RPM - unlubricated 
Pressure: Vacuum internal side / 1 ATM external side
Temperature: 40° - 90°F

The customer knew any kind of off-the-shelf rotary seal with a rubber element would not last any amount of time in the combination of speed and a dry running condition. They also knew a single lip PTFE seal would likely not meet their leakage requirements.

Therefore, they turned Eclipse for a custom sealing solution.

The Eclipse Solution

Eclipse is frequently challenged by our customers with difficult rotary sealing applications. In most cases, something like a commonly available oil seal is tried with unacceptable results. In this case, the combination of high surface speed and the dry running condition would quickly spell doom for any elastomeric or rubber sealing element.

While a simple cased single lip PTFE seal would certainly perform adequately in terms of wear life, Eclipse knew the customer would not be happy with the level of leakage control in a vacuum sealing application. Thankfully, Eclipse’s years of seal development experience has yielded a number specialty and unique design features to enhance seal performance in such demanding situations.

Eclipse developed its Crimped Case Seal (CCS) to work in just such applications. A CCS features a machined case in which the sealing lips are installed into small ID grooves. The case material is commonly Aluminum but can also be various grades of Stainless Steel. Using a press, the groove is then compressed to crimp the sealing lip(s) in place. The groove geometry is carefully designed to allow for an exact amount of contact and pressure to provide a fully sealed interface and secure anti-rotation of the lips.

In medium or low volume applications the CCS is ideal because when compared to a traditional rolled can lip seal, it eliminates both internal gasket and spacer components. The CCS therefore requires no special tooling or machine set-up charges, making it optimal for prototype and low quantity applications.

Because Eclipse’s CCS seals are machined, made to order, they can be customized for specific sizing and feature requirements. Knowing that high sealability in vacuum was critical for this application, Eclipse chose to incorporate a unique design feature that’s only possible on a CCS. An O-Ring groove can be integrated into the outside diameter of the machined case. An O-Ring specific to the application can then be used to provide a redundant and higher level of sealability on the OD of the seal.

The case of a CCS is still designed as a press-fit into the hardware, and in standard situations this is enough to provide adequate sealing around the outside of the seal. When a critical level of leakage control is required, the O-Ring supplies sealing assurance against any hardware machining imperfections or surface finish irregularities and should outperform any OD case coating available on traditional seals.

The second specialized feature Eclipse incorporated was the use of dual sealing lips. While this is not too uncommon in PTFE lips seal, Eclipse’s design differentiates itself by using both a machined lip and a formed lip. In this case, the machined primary sealing lip was designed with a precise angle of contact allowing for exact interference control and defined point loading. In other situations, the machined lip thickness and design can be tailored to handle higher pressures or for extended wear life.

The secondary sealing lip, which would be formed on a mandrel in the tradition fashion, provides a long lay-down on the shaft and therefore a large contact patch. Especially in sealing vacuum, this long effective sealing distance helps create a greater sealing barrier.

The combination of both sealing design principles, point loading and long lay-down, give the seal the best opportunity possible of sealing with minimum leakage. Eclipse chose its ET013: Fiberglass/MoS2 filled PTFE for the lip material which would deliver a good mixture of wear life, sealability and lubricity.

Eclipse had one more additional design element to employ. A dual lip design allows for the use of a grease pack between the sealing lips. Adding a grease pack does two things. First, it creates a tertiary sealing barrier. Much like the lay-down of a formed lip, the grease can create an additional leakage impediment partition. Second, the grease will provide much needed lubrication to the primary sealing lip. This can help the lip to break-in properly and extend service life.

The type of grease used can be customized to the specific application. Whether it be vacuum grease, as in this situation, or greases with specific properties to help performance, such as ones containing solid lubricants like MoS2. Eclipse has also used very specialized greases ranging from FDA compliance specific to focused water barrier protection.

How it Performed

The customer was delighted that Eclipse’s Dual Lip CCS provided both acceptable levels of leakage control and seal wear life. The advanced features of Eclipse’s design let the customer operate their vacuum chamber at the desired levels without any additional or upgraded pump-down equipment. The specialized features including the combination machined and formed lips, O-Ring OD, and grease pack all contributed to the sealing success of the system.

Contact Eclipse today if a rotary sealing solution is needed for your application. >

Case Study: PEEK Spring Energized Seal in a High Temperature/High Radiation Application

Mon, 25 Nov 2024 21:25:00 GMT

Eclipse has engineered sealing solutions for applications all over the planet and in a plethora of environments. From the bottom of the ocean to orbiting the earth, Eclipse is challenged by the unique conditions in each application. Whether it be extreme temperature and pressure or severely caustic or abrasive media, Eclipse has a solution for most every sealing problem.

One distinct environment presents a particularly challenging set of circumstances for seal design – high radiation. Eclipse’s primary seal material choice for many applications is PTFE and PTFE blends. With all the wonderful attributes PTFE possesses as a seal material, radiation resistance is not one. In high radiation environments PTFE’s properties can degrade to essentially rule it out as a suitable material.

The options for effective sealing materials that are also radiation resistant becomes very limited. The seal designer is therefore confronted with creating a seal that is expected to perform in every way a typical PTFE seal operates, out of materials that are not as favorable to sealing. This is where Eclipse’s engineering experience and expertise in seal design come to the forefront.

The Client's Issue

Eclipse was approached by a customer that was looking for a seal solution for a sensor used in a nuclear application. It would be operating in an environment with both high temperature and high Gamma radiation.

Operating Conditions: 
Reciprocating Rod Seal 
Rod Diameter: Ø1.000 
Stroke: 1.5” Cycle Rate: 2-4 cycles per minute 
Media: Air, Salt Water Mist 
Pressure: 100 PSI 
Temperature: 70° to 450°F 
Gamma Radiation Exposure: 10^6 rads

Aside from the radiation exposure, this would be a relatively mundane sealing application for one of Eclipse’s PTFE Spring Energized Seals. But that level of radiation quickly eliminates PTFE as a suitable seal material and greatly complicates the seal design.

PTFE’s Limitations in Radiation

PTFE’s has many benefits as a seal material. It’s noted for its low friction, high temperature and chemical resistance. At Eclipse, PTFE based seals are our primary business, whether it be O-Ring or Spring Energized Seals . With all the many of advantages of PTFE, unfortunately it cannot be utilized in high radiation environments. When compared to other common plastics, PTFE actually is one most susceptible to radiation degradation.

Radiation has an embrittlement effect on PTFE, exposure degrades PTFE’s tensile strength and elongation properties. High enough levels and exposure time can actually casue PTFE to crumble and ultimately be reduced to a powder. Unfortunately, tensile strength and elongation, which dictate a materials flex characteristics, are some of the the most important properties when considering a material for a seal.

The threshold for radiation damage of PTFE is 2 to 7 X 10^4 rads. Depending on exposure time, dosages above this level will likely compromise PTFE’s tensile and flex properties. It is important to note that in vacuum, the damage threshold is about ten times higher. Therefore, in space applications such as in orbiting satellites, PTFE might still be an effective seal material against normal space radiation.

In the case of UV radiation, PTFE is actaully very resistant. PTFE will not degrade or age in longterm sun exposure situations. But with this application is operating in Gamma radiation at 100 times the accpetable limit for PTFE, an alternative material would be necessary. This where Eclipse’s advanced knowledge of seal design and material characteristics come in.

The Eclipse Solution

When PTFE can’t be used as a seal material due to radiation, two materials are often firstly considered. ETFE, which has many of the same properties of PTFE in terms of sealing, is typically the preferred Gamma radiation resistant seal material. It can withstand levels up to 10^7 rads. But unfortunately, for this particular application, the upper operating temperature of 450°F ruled out the use of ETFE which is typically rated only to 300°F.

It would be worth mentioning that ETFE’s market availability can be much more limited than common PTFE and can cost many times more. For very large seal sizes ETFE can potentially be cost prohibitive as a material. Which leads into the other common radiation resistant material, FEP.

FEP again, can act very similar to PTFE in terms of sealing qualities but withstand radiation levels 10 to 100 times greater. While this would get us into the needed range for resistance, the customer was uncomfortable with no safety factor or security margin. Plus, the operating temperature again would be at or over FEP’s normal stated maximum.

So, with both common high radiation seal materials ruled out, Eclipse turned to a familiar, but rather unconventional seal material – PEEK. PEEK possesses one of the highest radiation resistances out of all commonly available plastics. It can withstand exposure in the range of 10^9 rads before any property deterioration occurs. PEEK can also successfully operate at temperatures up to 500°F.

Second only to PTFE, PEEK is frequently being turned in Eclipse’s in-house machine shop. PEEK is typically used for back-up rings, bearings, and structural seal components such as seal carriers and valve blocks. But the material properties for PEEK that make it great for products needing high strength unfortunately also hurt it for being used as a seal material.

PEEK is considered a “high modulus” material, the percent elongation before break for Virgin PEEK is only 25% and hardness is 85D. Virgin PTFE by comparison is 400% with a hardness of 55D. Obviously, a material that is softer and can flex freely would be more desirable as a seal. The more a material can conform to the sealing surface the better the resulting seal will be.

Eclipse’s challenge would be to create a spring energized seal jacket out of PEEK that still flexes and compiles enough to generate an effective seal. This was accomplished by carefully controlling the lip thickness of the jacket and precisely defining the hinge point. A very thin sealing lip would be easy to flex, but this would also compromise wear life and pressure handling ability, especially at elevated temperature. A sealing lip that was too thick would not allow the spring to function properly or provide energy in the correct area.

Eclipse’s experienced design engineers constructed the perfect balance of flexible lip thickness and robust design. Comparatively speaking though, the resultant lip thickness was very thin when sized against a typical PTFE lip design. At only roughly 0.012” thick, Eclipses precision machining ability would also come into play to ensure the necessary tight tolerances were met.

Eclipse chose its EP033 : Virgin Grade PEEK for this application. Any material fillers would further degrade PEEK’s elongation properties. Eclipse also upgraded the cantilever V-Spring material to Elgiloy® for improved performance in the stiff jacket and greater corrosion resistance.

How it Performed

The customer pleased to know they could count on an effective seal at even their worst-case radiation levels. Eclipse’s detailed design and precision machining resulted in a successful sealing solution from the most radiation resistant materials available.

Contact Eclipse today if your high radiation environment is causing sealing problems or a new seal design is needed >

Case Study: MicroLip™ – Robust Rotary Sealing in Cutting-Edge Robotics

Thu, 14 Nov 2024 20:33:49 GMT

Technological advancements in the area of robotics have led to more and more life-like creations existing only in works of science fiction a few decades ago. Development in autonomous logic processing and sensing allows bipedal robots to walk over uneven ground, up and down stairs, open doors and carry loads. Fast response to dynamic and unpredictable real-world environments is critical for the future use of robots in true-life service and practical employment in the years to come.

While software and sensor development remain the primary focus of most research, the physical mechanics of next-gen robotics are also continually progressing. Physical components and control systems such as hydraulic pumps and cylinders, servo motors, and structural members are under pressure to continually be lighter, stronger, more efficient and less expensive.

Increased demands on the physical components facilitate the need for innovative solutions in design and material usage.

Advancements in construction and technology have spilled into all areas of robotic mechanisms and the many seals located throughout the system need to meet the challenges of tomorrow. Eclipse has been at the forefront of this research and has developed innovative solutions pushing the boundaries of conventional sealing devices.

MicroLip™ by Eclipse is a prime example of most demanding applications forging new technologies in the sealing world.

The Client's Issue

Eclipse was approached by a leading robotics company looking for a sealing solution operating under a challenging set of conditions. While many components of tomorrow’s robotics are now controlled and actuated by servo/stepper motors and various electronic devices, the heaviest and most powerful movements are still driven by traditional hydraulics.

The constant demand for more powerful hydraulic actuation in ever deceasing size and weight requirements has put tremendous strain on component design. But if robots are to progress to the point where they are usefully employed in the world, high power in a compact design is necessary. A robot, for example, used to survey and assist in a disaster zone too unstable for normal rescuers, must fit through doorways and over obstacles yet still be physically strong enough to render assistance.

Large hydraulic systems are capable of moving extremely heavy loads but size and weight constraints of a humanoid size robot limit potential. The robot’s internal power supply to drive all components is also a limiting factor.

Our client was developing a new hydraulic pump to drive all major motion aspects of their robotic systems. Their main objective was to minimize the pump’s physical size as much as possible while increasing output and improving power consumption efficiency. This means higher pressures and speeds on increasingly smaller and lighter components.

Application Parameters:

Shaft Diameter: Ø9.5mm

Seal Housing Envelope: 5mm radial cross-section by 6mm axial width

Rotational Speed: 3,500 RPM nominally; 6,000 RPM max

Operating Pressure: 125 PSI min, 225 PSI nominal, 350 PSI max

Surface Finish: 0.04µm

Media: Hydraulic Oil

While the above combination of pressure and speed might present difficulties for any conventional seal alone, the client’s extremely small physical envelope to house the seal further complicated the matter.

If that wasn’t enough, the application presented the additional sealing challenge of up to 0.003” [0.08mm] of shaft runout. As part of the downsizing of all components in the pump, shaft support bearings were minimized leading to the possibility of runout. The wobbling effect of the shaft creates problems as the sealing lip has follow a moving, uneven mating surface, therefore potential leak-paths are created. Wear life can also be compromised due to higher concentrations of uneven loads.

The combination of high pressure, high speed, high runout and minimal gland size present a worst-case scenario for a typical seal. Unsurprisingly, the client faced leakage of hydraulic fluid after only short periods of service with any conventional seal they had tested.

Eclipse knew the had the perfect solution for this application. One developed to handle such extreme rotary sealing conditions: MicroLip™.

The Eclipse Solution

MicroLip™ was developed after many demands from customers wanting more performance in rotary applications. Increased rotational speed at higher pressures on smaller and smaller components has been prevalent in medical and aerospace industries but robotics and autonomous vehicles have been a primary driver. With weight and size reduction at the forefront combined with the limited power-supplies of onboard batteries, the need for a new advanced seal was needed.

Eclipse met this demand with a brand new, unique sealing solution: MicroLip™ . Metal cased, PTFE lip seals are nothing new in the sealing industry, but their use of stamped and formed components limits their small size range. This combined with their inability to handle higher pressures or significant shaft runout ruled out their use in applications such as this.

MicroLip™ solves these limitations by exclusively using precision-machined components. With the sealing lip a machined element, things like interference and lip lay-down can be carefully controlled allowing Eclipse’s design team to tailor specifications for every application. Friction control and seal-to-seal variability are greatly improved over a traditional formed PTFE lip. At the same time, increased pressure handling can be achieved from the custom designed element.

Advantages by machining the metal elements are also realized other than the key ability to provide solutions for shaft sizes far below 1” in diameter. Because no stamping dies or forming fixtures are required lead-times and material minimums are greatly reduced. Therefore, prototype quantities of custom designs become much more accessible.

Eclipse solved the additional problem of large shaft runouts but incorporating a garter spring on the sealing lip. The machined lip design allows a small ledge for retention. The garter spring provides a constant inward, radial pressure ensuring the lip follows and conforms to the motion of the shaft. Even in high eccentricity and runout situations the lip is always in proper contact with the shaft, all while working within the small footprint of the seal.

Eclipse knew MicroLip™ was the perfect solution to the customer’s challenging hydraulic pump application.

How it Performed

MicroLip™ proved to provide a long service life of leak free operation in the customer’s application. They had grown accustomed to dealing with frequent rebuilds and cleaning up leaked hydraulic fluid with their old seal configuration. They were very excited Eclipse’s sealing solution finally allowed a product that could be fit for field use and larger scale production.

Contact Eclipse today if MicroLip™ could be right for your challenging rotary sealing application >

Case Study: Custom PTFE Tri-Clamp Gaskets Keeping the (Good) Beer Brewing

doug@eclipseseal.com (Doug Montgomery) — Mon, 14 Oct 2024 21:56:39 GMT

It’s no secret the craft beer industry has exploded in the past decade across the country. The number of microbreweries in the United States has more than tripled since 2012. Sales of craft beer topped $28 Billion in 2023 nationwide, making it big business for many state’s economies. Eclipse’s home state of Colorado has been at the forefront of the brewery wave, ranking fourth in the country for number of craft breweries at over 450.

Healthy demand for new and exciting beer types has found many small, niche breweries scrambling to produce enough beer to satisfy the market. Breweries starting in mere garages find themselves expanding to fill entire warehouses and previously occupied manufacturing facilities. The need for larger and higher scale brewery production equipment has therefore increased accordingly. Of course, beer production is dependent on seals not only for leakage control, but also product quality and consistency.

Keeping it Clean

The beer brewing process requires the raw dry ingredients/water to be transferred several times from vessel to vessel at varying stages of the procedure. In a larger-scale brewery, the raw ingredients (and subsequent beer) might be transferred into five or six separate tanks from the beginning of the operation to end. In addition, there also might be cooling steps through heat exchangers and filtering procedures.

Transferring the raw ingredients and/or beer is done through pipelines or specialty hoses. The most common connection type for the hose or piping is a flanged Tri-Clamp fitting. This type of connection, sometimes called a sanitary clamp, is widely used in the food/beverage industry , as well as in biotech and pharmaceuticals. It facilitates a relatively easy, often tool-free, connection and disconnection while still providing good sealing force. The clamp utilizes a gasket in the connection which are usually referred to as sanitary gaskets.

They can be made of various rubber and elastomeric compounds, as well as PTFE . A PTFE gasket is often used in high temperature areas of the equipment, such as near burners or heating elements.

While it’s obvious, leak-free connections are desired in the brewing process, keeping the beer in is as important as keeping contamination out. Cleanliness is very important in the brewing method as any unwanted bacteria introduced at any point in the process can spoil an entire batch of beer.

Unlike Sour or Farmhouse beers where the use of wild yeast is purposely introduced and controlled to produce a desired level of funkiness, bacteria due to unclean vessels or leaking seals can cause a rancid or foul batch. Out of control fermentation can also take place depending on the stage of introduction.

While a small brewery can pass off a few barrels of a funky batch as an experimental brew in their tap room, a brewery in a high volume canning and distribution arrangement will have expected standards of quality and consistency. One unsavory can or bottle can potentially harm the image and brand of an entire brewery.

The need for effective and properly functioning seals throughout the brewery process therefore becomes increasingly important. As production volumes steadily climb the potential for issues also multiples.

The Customer’s Issue

Eclipse was approached by a local brewer undergoing an expansion and looking to utilize some very old, almost historic, brewing equipment. While the vessels and tanks were all usable and totally functional, a major problem came about when they attempted to change the seals. Most of the hose and pipe connections, while a familiar Tri-Clamp style of connection, were very odd sizes. The equipment was made in Europe well before any type of standard seal/gasket connections where designated.

A typical Tri-Clamp gasket today is considered a commodity item and can be found on-the-shelf from many vendors, even in PTFE. Most are very limited in available sizes and typically only include inch nominal selections. The customer’s hardware was based off non-standard, metric sizing so finding an off-the-shelf gasket was not going to be possible. To make matters worse, many of the connection flanges were heavily worn from years of use, making sizing of the gaskets even more of a challenge. Unlike a rubber O-Ring, where it might be possible to stretch or compress a standard size to fit, a PTFE seal must be properly sized to work.

The customer faced a dilemma. Re-tooling every connection to use standard size gaskets (which would involve welding of new flanges at every hard connection point) would likely offset any cost savings the customer gained by utilizing the old equipment. They would probably be better off just buying a completely new brewing system and tanks if the proper gaskets couldn’t be found.

Fortunately, Eclipse had a design, manufacturing and service solution to the customer’s problem.

The Eclipse Solution

Eclipse is quite regularly tasked with reverse engineering seals for customers in similar situations. Often, a used seal is the only thing that can be provided, and Eclipse is up for the challenge of making a fully functioning seal with that limited information.

The customer supplied Eclipse with the original, used and worn seals to measure and reverse engineer. There would obviously be no engineering drawings of the hardware to review. Eclipse’s very knowledgeable, technical sales staff was able to assist the customer in measuring the accessible hardware at their facility. Their expertise in sealing systems and knowing the critical dimensions for sealing success, helped Eclipse gather as much information as possible about the application. Though highly precise measurements are typically not possible in the field, any information on seal gland dimensions will aid in the reverse engineering of the system.

Unfortunately, not all aspects of the hardware were practical to measure. So simply designing a new seal or gasket around a set of dimensions would not be possible. Eclipse’s engineering staff would need to examine the used original seals to determine the missing pieces of the puzzle.

Eclipse possesses a wide range of measurement and inspection equipment. From comparators to micrometers and depth gages to our advanced, highly precise Visual Measurement Machine. But simply measuring and duplicating the heavily worn seals would not necessarily spell success.

This is where Eclipse’s many years of seal experience comes into play. While measurements of the existing seals provide value information, understanding the functionality and design intent of the seal is critical for the ultimate success of the system. Knowing what dimensions will be key and the behavior of the seal material play an essential role in final sealing fitment and performance.

Eclipse combined all the available information together with its proficiency in seal design to produce new seals for some very old equipment.

How it Performed

The customer was thrilled that Eclipse was able to retrofit new seals into their hardware. Eclipse’s custom designed and manufactured seals proved to fit perfectly.

The equipment was bought online leak free in all the connections. The customer was also very pleased in Eclipse’s level of personalized, knowledgeable service and timely response of the technical sales team.

Eclipse’s prompt lead-time from its in-house manufacturing gives the customer a reliable source for quality PTFE seals and gaskets for years to come.

Contact our team to learn more about how we can assist you >

Case Study: Custom Piston Seal Rings for Composite Bores

doug@eclipseseal.com (Doug Montgomery) — Tue, 10 Sep 2024 20:08:27 GMT

Elastomeric or rubber O-Ring find their way into many applications, whether it be highly technical aerospace equipment or budget-friendly consumer products. This typically is for good reason. Unassuming O-Rings provide a great sealing interface in most situations, are easy to install, and are available on-the-shelf for minimal cost.

Many projects at Eclipse Engineering start with a customer first using an O-Ring. But if a customer is contacting Eclipse, it usually means either the O-Ring is failing or not performing up to their expectations. Many circumstances can cause O-Ring failures, such as chemical incompatibility or temperature extremes. In many cases Eclipse has a PTFE seal solution for the application.

In this study, we’ll find a customer having success using an uncomplicated O-Ring in a product currently in production. They were simply looking for an upgrade in the sealing system for improved product performance and adding selling points. Eclipse had just the answer.

The Client’s Issue

Eclipse was approached by a customer looking for an enhanced solution for a piston seal in their air compressors. They were currently using a carboxylated Nitrile O-Ring as the sole piston seal. While working satisfactory, there were a few limitations the O-Ring presented that the customer wanted to improve upon.

First, the O-Ring required lubrication in the bore to function. If lubrication was lost or insufficient in the system, the O-Ring would quickly over-heat due to friction and fail. The customer saw this as a long-term liability for their unit and wanted a seal that was capable of dry running if needed.

Second, they wanted to extend the wear life of seal to increase the maintenance intervals of the compressors. Changing out the O-Ring required extensive disassembly of the compressor which meant long down-times. Fewer required services per year could be marketed as increased productivity for current and potential end-customers.

Operating Conditions:

Reciprocating Piston Seal
Bore Diameter: Ø5.500”
Media: Air
Pressure: 200 PSI
Temperature: -40° to 200°F
Stroke Length: 2”

The Eclipse Solution

Eclipse’s ESR piston seals are perfect for application like this. Their long wear life and high-pressure handling make them specifically suited compressor type applications. But the customer’s hardware was already in production, and it was designed around an O-Ring groove.

More specifically, the hardware was a fiberglass/resin composite. There was no chance of the piston design being changed at this stage in of the production cycle. Unlike metallic parts that are machined, a simple programing change is not possible. Eclipse would have to work within the current hardware dimensions.

The fact the bore and piston were a composite material presented Eclipse with its next challenge. Eclipse has many PTFE blends, such as EZ032 and ET019, that are purposely meant for prolonged seal wear life. Their fillers are aggressive in nature and are designed to work against specially hardened surfaces or coatings. A blend like this would certainly destroy the composite bore in short order.

Therefore, Eclipse had two main design constraints: using the existing O-Ring groove and choosing a long-lasting material that wouldn’t damage the composite hardware. A simple application for a relatively common piston seal ring, just got a whole lot more complicated.

Starting with the design, Eclipse actually has a standard seal ring offering designed for situations like this. Eclipse’s EDS Piston Channel Seal seals are meant to retrofit on top of O-Rings in standard grooves without modifications. This provides a PTFE interface with the bore and all the benefits that come along with this.

But in order to work with the O-Ring in the standard groove, the PTFE thickness must be very thin to avoid the potential for over-occupancy. The O-Ring compression, set by the hardware groove depth, is not meant to have the additional PTFE material contributing to the squeeze. Consequently, the web thicknesses of channel seals are typically only around 0.010”.

Therefore, a Channel Seal is normally used in light duty applications where reducing friction is the primary objective. Eclipse knew the customer would not be happy with the marginally extended wear life of a channel seal and a more traditional piston seal ring would be necessary.

In order to facilitate a thicker seal ring, Eclipse chose to use an uncommon, yet available, metric O-Ring in the groove that was smaller in cross-section. There was a very fine balance between having a small enough O-Ring so sufficient seal material could be used, while not compromising stability in the groove.

An O-Ring that was too small would allow the possibility of the seal shifting improperly in the groove creating problems. An O-Ring that was too big would not permit enough seal material for long wear life. Eclipse managed to find the correct balance without needing a custom molded elastomer.

For the seal material selection, Eclipse chose it ET014: Polyimide filled PTFE. ET014 has become a staple at Eclipse Engineering for it’s good sealability and high wear resistance without being abrasive to soft hardware.

Traditionally, blends like Graphite filled PTFE have been used in these situations, especially in air sealing. ET014 has many of the same characteristics without the graphite particle generation during operation.

How It Performed

The customer started testing Eclipse’s piston seal ring design in the worst-case dry running condition. They were thrilled to find the seal still functioning sufficiently after over 3 million cycles. With proper lubrication, the piston seal would now function for the entire intended life of the compressor.

This is something the original O-Ring could not even come close to achieving. Ultimate integrity of the composite bore material would now be the limiting factor in the service life of the system.

Eclipse accomplished this all while utilizing the current hardware only intended for an O-Ring. The customer could therefore significantly improve the current compressor performance with minimal investment since no major molding or structural components needed to be changed.

Dry running capability and massively increased service/maintenance intervals presented the customer with a competitive advantage and increased marketability of their product.

Contact Eclipse today if your application can benefit from a custom engineered seal ring >

Case Study: Customized Cryogenic Face Seals for Liquid Oxygen Rocket Turbopumps

doug@eclipseseal.com (Doug Montgomery) — Tue, 10 Sep 2024 19:49:20 GMT

The space race is on! While headlines about returning to the Moon or manned missions to Mars garner most of the attention, commercial space launch platforms and services have become increasingly utilized and prevalent.

With demand for services provided by low orbit satellites ever expanding, there is no shortage of new launch vehicle requests. The communications, navigation, and weather services most people have become accustom to are all made possible by the thousands of satellites orbiting the Earth each and every minute.

While safety and reliability will remain the top priority of every launch, the success of a launch system has ultimately changed to be decided by one important merit – cost. In fact, the cost per kilogram of payload is often the prevailing factor in determining the commercial viability of a system.

New competition from privateer launch companies in the US, as well as state run programs from foreign countries around the world, have reset the economics of putting an object in orbit. While technological advancement has never ceased, the main focus has shifted to developments in reducing cost.

Whether it be innovations in performance or production/operating economy, components in the complex launch systems need to adapt to the new challenges. Its obvious seals play an important role in the success of a rocket launch and engineers are increasingly asking more of the sealing systems.

The Client’s Issue

Eclipse was approached by a designer and manufacturer of turbopumps used in rocket engines. A turbopump is used to supply high pressure fuel and oxidizer into the combustion chamber of a rocket.

The separate components of the turbopump need to be sealed at their mating points in a static face seal configuration. Seals are needed on both the fuel and oxidizer sides of the pump.

But the oxidizer, in this case Liquid Oxygen (LOX), presents the much greater sealing challenge due to the cryogenic operating temperatures.

Operating Conditions:

Internal Face Seal
Static
Gland Outer Diameter: Ø6.250
Media: LOX
Pressure: 2,000 PSI
Temperature: -335°F to +70°F

When sealing gases at cryogenic temperatures the surface finish of the hardware becomes critically important for leakage control. The low temperatures of cryogenics effectively harden any seal material reducing its ability to conform to hardware surface imperfections and machining grooves. In most cases, a surface finish of 6µin Ra or better would be recommended.

Finishes in this range would be considered “mirror-like” and almost certainly require secondary grinding, lapping, and honing to be achieved. Within a seal groove that must be milled, these operations can be difficult and time consuming to perform, therefore add significant cost.

Being a complicated and precision component, the turbopump can represent a substantial portion of the entire launch vehicle’s cost. Any efforts to reduce expenses in this area would have a meaningful impact on the program’s budget. By forgoing any secondary polishing process in the seal grooves, manufacturing time of the turbopump components could be lessened by a considerable amount and subsequent savings could be realized.

The best achievable surface finish without any secondary processing or operations would be somewhere around a 16µin Ra. While this is great in terms of potential cost savings, designing a successful seal under these conditions becomes challenging. On top of this, the seal itself would be under scrutiny to be as cost-effective as possible.

Eclipse was nevertheless, up for the task.

The Eclipse Solution

When dealing with cryogenic temperatures a spring energized seal is almost automatically chosen. The type of spring used can be decided based on the application though. Eclipse offers three types of springs that can be used to energize seals: Cantilever V-Spring, Canted Coil, and Helical. Each spring has its own advantages and drawbacks.

Helical spring is often used in cryogenic applications. It offers some of the highest unit loading of all the spring types. This is very desirable at cryogenic temperatures to ensure the seal remains energized keeping the sealing lips properly engaged and loaded in the hardware.

Eclipse knew that, as part of the cost savings efforts of the launch program, the seals would need to withstand multiple assemblies and uses. Helical spring has a good chance of being yielded or taking a set after one installation, so it is typically not recommended for multiple installs.

The other options would be Canted Coil and Cantilever V-Spring. Canted Coil’s relatively light and constant load curve, while great for rotary application would not be well suited here. V-Spring would be the correct choice. Good point loading and high resiliency to multiple compressions would be fitting for the application. V-Spring, in most cases, is also the most cost-effective spring due to lower raw material cost and higher run-rates for cutting, welding, and assembling into seal jackets.

With the relatively poor hardware surface finish, spring force would be critical in providing the best seal possible. Eclipse chose to incorporate two nested V-Springs to both increase spring loading and the energized area at the hardware/seal interface.

Turning to the seal jacket, at cryogenic temperatures only a few materials are commonly used. In static situations, typically unfilled or Virgin grade materials are chosen to ensure the best pliability and conformity as possible. PCTFE is known for it’s excellent sealing characteristics and mechanical properties even at temperatures as low as -400°F, but it also very expensive.

Eclipse chose its ET000: Virgin PTFE for the seal jacket material. While being one of the most simple and common materials Eclipse has available, it would fit all the desired characteristics needed for the application. Good elongation and pliability attributes at low temperatures, as well as, being extremely cost effective.

Eclipse also customized the seal jacket design and geometry. The lip thickness was carefully specified to maximize the spring force energy and maintain flexural capabilities. This was finely balanced with the need for high pressure structural integrity of the seal.

How It Performed

Eclipse’s choice of nested V-Springs and a custom ET000 seal jacket proved to be a winning combination. The seal met the customer’s leakage requirements even with their relatively poor hardware surface finishes.

This, combined with a very cost-effective seal itself, helped meet the overall budget goal of the launch system. This positioned the customer to be competitive in an increasingly crowded market of options to leave the planet, proving that great engineering can drive both reliability and affordability in critical aerospace applications.

If you're in need of efficient and effective problem-solving, contact our team today to find out how we can help you >

Case Study: Replacing V-Packings with Nested Spring Energized Seals

doug@eclipseseal.com (Doug Montgomery) — Tue, 13 Aug 2024 19:15:13 GMT

V-Packings, also called V-Stacks or chevron packings, have been around for decades and represent one of the earliest advanced sealing designs. While existing long before PTFE spring energized came into being, they are still used in a variety of industries today. Eclipse designs and manufactures its fair share of custom V-packings out of various materials every year.

V-Packings offer a simple yet effective design principle. A series of nested “Vees” are arranged in a gland where the points of the Vees serve as the sealing contact points in the hardware. They are designed in such a way that if the stack is compressed axially, the Vee behind will expand the radial cross-sectional width of the Vee in front of it. This will provide the needed energy to force the contacting sealing points into the hardware surfaces.

Compression force is usually provided by a packing nut in the hardware. The more the stack is compressed, the tighter the sealing potential. This offers big advantage over other simple seal designs such as rope packings because the seal can be energized in focused locations. If leakage is occurring, tightening the packing nut if often all that’s needed.

V-Packings are often used in heavy industrial applications where a robust and substantial seal is needed. The numbers of Vees in the stack represent the number of effective sealing points. Eclipse has designed manufactured packings with up to ten Vees, but the only real limit is axial gland space in the system. In these heavy industrial applications, the ability to affect sealing performance by turning a wrench is well utilized where system maintenance is regularly performed and monitored.

While V-packings can work well in the right application, there are drawbacks to the design. A spring energized seal offers numerous advantages over V-packings and in many cases can outperform them in all major sealing aspects.

The Client’s Issue

Eclipse was approached by a customer looking for improved efficiency and longer seal wear life in their Natural Gas compressor. The compressor piston rod seal was currently using a Virgin PTFE V-Packing, and while it was working sufficiently, the customer was looking for improved compressor performance. All system aspects were under review for enhancement, including the seals.

Operating Conditions:

Reciprocating Rod Seal
Compressor Type: Single Acting, Crosshead Piston
1.125” Rod Diameter
Stroke Length: 4”
Piston Speed: 850 FPM
Media: Natural Gas
Operating Pressure: 5,000 PSI

The Eclipse Solution

Eclipse knew that replacing the current V-Packing with a spring energized seal could potentially provide the customer with all the improvements they were looking for. While V-Packings certainly serve their purpose, they have a few limitations and drawbacks a spring energized seal does not.

The only energy applied in a V-Packing is from the initial compression in the hardware. In the case of PTFE, where it’s material properties essentially provide zero internal energy or elasticity, the initial compression energy will eventually diminish as the material relaxes and becomes worn.

Thus, a V-Packing will need maintenance over its lifespan. If leakage starts occurring, tightening the packing nut, or compression device will be necessary. But this also leads to a major disadvantage of a V-Packing with the imprecise way of loading the seal. A stack needlessly compressed too tight will experience accelerated wear and introduce excessive friction on the shaft.

A spring energized seal solves this problem. Its internal springs are a known and calculated value, providing the optimum sealing load at all times. This loading can be tailored to the application whether heavy scraping is needed or extreme low friction.

Unlike a V-Packing, the spring will properly load the seal over its entire wear life. Therefore, essentially maintenance free operation is possible along with much more consistent loading and friction. The seal is no longer dependent on an operator to adjust as needed.

Many customers like the fact that a V-Packing has multiple sealing points for redundancy. In a retro-fit situation, as in this case, the customer wanted to retain this aspect of the seal. Eclipse replicated this feature by using nested cantilever V-Springs within the seal jacket. The external seal lips were machined with point contact locations the correspond to each spring. Thus, multiple energized contact points were maintained.

Whereas a V-Packing uses separate rings to achieve these redundant sealing points, the spring energized seal accomplishes this in a single, self-contained seal. It is no longer necessary to assemble the separate rings during installation, reducing part count and eliminating the potential for assembly error.

Eclipse chose its ET014: Polyamide filled PTFE for the seal jacket material. While Eclipse can custom machine a V-Stack set out of any of its filled PTFE options, most V-Stacks are usually just Virgin PTFE by default. This leaves a huge potential for wear life improvement by switching to a filled PTFE material. Eclipse used ET014 because the customers shaft hardness was below what was recommended for aggressive fillers. ET014 would provide a significant improvement in wear life while not damaging or deteriorating the hardware.

How It Performed

Eclipse’s spring energized seal met all the customer’s objectives in improving the efficiency and maintenance intervals of their compressor. The spring energized seal provided lower and much more consistent friction therefore improving the overall running efficiency of the whole mechanical compressing system.

The seal also no longer requires regular attending to perform optimally. This combined with the longer wearing ET014 seal material extended rebuild intervals greatly, thus saving the customer both time and money. The reduced part count and ease of seal installation were an added bonus to the project.

Contact Eclipse today if you think you can benefit by replacing a V-Packing with a custom spring energized seal >

Case Study: Advanced Seal Technology in Automotive Racing Shocks

doug@eclipseseal.com (Doug Montgomery) — Tue, 13 Aug 2024 19:02:08 GMT

Automotive racing has always been a source for technical innovation driven by the constant pursuit of the competitive edge. With the top racing teams in the most popular worldwide series having annual budgets approaching half a billion dollars, the cost to win has never been higher. Research and Development budgets have been reported as high as 100 million dollars per year alone.

Great advancements in racing technology have undoubtably resulted from this expenditure and commitment to winning. But the financial burden to compete has also limited and excluded many smaller teams from competition. In efforts to promote a more accessible contest and attract a more diverse field of teams and drivers, some racing leagues and series have moved to “spec” chassis and engine requirements.

This means the entire field uses the same components supplied by one or two manufacturers and no development or modifications are allowed by rule. This drastically reduces the cost to compete for individual teams and promotes close racing as no one has a significant technical advantage, putting more focus on the driver’s skills.

Such close racing has forced teams to look for any advantage in performance they can find. With the rules limiting changes to most major systems, teams have focused on making improvements to smaller, unregulated components. Suspension dampers, or shock absorbers, are a chief area of development. Complicated internal valving and structuring has meant the need for advanced seals is at the forefront. This is where Eclipse comes in.

The Client’s Issue

Eclipse was approached by a top racing team looking for improvements in the internal sealing system of their gas shocks. A damper works by carefully controlling fluid flow through specially designed orifices and flow passages. This metering manages the response of the combined spring to control how the suspension works over bumps and cornering g-forces.

The customer was currently using rubber X-Rings as the primary piston seals in their shocks. For dynamic applications, such as a shock, a X-Ring can provide a significant improvement in friction and performance over a standard O-Ring. They work by limiting the surface contact and load of the seal, enhancing the dynamic operation. While the X-Rings were technically sealing fine, the team was looking for any improvements they could find in friction reduction.

With shocks having to respond to inputs from the road or track in milliseconds, any reduction in sealing friction will result in better performance as forces are better translated to the designed components. Lower friction means a smoother and faster response time and a more efficient damper by more completely directing the dynamic motion through the carefully designed valving and not being dissipated as heat.

Eclipse was challenged to replace the X-Rings with the lowest friction seal possible without compromising life or sealability.

The Eclipse Solution

Eclipse immediately knew the first order of business was to change to a PTFE based seal. More specifically, Eclipse chose their ET002: Molybdenum Disulfide (MoS2) filled PTFE as the base seal material. PTFE’s coefficient of friction can be as much as 10 times lower than that of rubber. The blending of a small percentage of MoS2, which is a common solid lubricant, also further reduces the friction coefficient. ET002 is ideal for applications where low friction is the chief concern. The addition of the lubricant further enhances PTFE’s already excellent dynamic sliding capability.

The next task was the choice of energizer for the seal. While a typical O-Ring Energized Seal would perform fine in terms of sealabilty and wear life, the friction due to the high unit loading of the O-Ring would be not acceptable in this application. Eclipse knew their Spring Energized Seals would be the right seal for the job, and their in-house manufactured Canted Coil spring would be precisely what was needed.

In dynamic applications, the most common spring types are either Cantilever or Canted Coil. When comparing the load versus deflection curves of these two springs, the Canted Coil has the unique property of having a virtual flat curve over a large portion of the deflection range. This means the load of the spring is almost constant over a range despite seeing increased compression. This is very different from Cantilever spring which has a linear response, more deflection equals more load.

This unique property of Canted Coil Spring makes it ideal for applications where friction control is very important. The seal can be designed to operate in this constant load range allowing the friction of the seal to very carefully be tailored to specific requirements. Eclipse used their light load Canted Coil Spring in combination with a custom seal jacket design to allow for a seal with the absolute lowest friction possible. All while ensuring positive seal engagement and not compromising seal wear life.

Looking at the complete sealing system of the piston, Eclipse thought they could take the design even further to reduce friction. The current piston utilized a polymer wear ring to provide guidance and prevent any metal to metal contact with the piston and bore. Eclipse designed the Spring Energized Seals to have a specialized extended heal geometry to properly support and guide the piston.

Extended heel designs are typically used to help extrusion resistance in high pressure applications. In this case, the tight tolerance heel was designed to take the place of the separate wear ring currently in use. The seal geometry eliminated the need for the wear ring permitting the use of a smaller, more compact piston which therefore also translates to less weight. A lighter piston means better response time within the shock improving overall dynamics and performance.

How It Performed

Eclipse’s seal design incorporating their ultra-low friction ET002 and precisely controlled canted coil spring load allowed for a massive reduction in overall system friction. The elimination of the piston wear ring by using specially designed extended heel seals meant further improvement to the shock absorbers performance. In a sport where fractions of a second can be the difference between first and fourth, the team was thrilled with the performance advantage made possible by Eclipse’s custom seal design.

Contact Eclipse today if an ultra-low friction Spring Energized Seal could be right for your application >

Case Study: PTFE Spring Energized Seal Provides Low Friction Performance in Food Product Dispenser

doug@eclipseseal.com (Doug Montgomery) — Tue, 09 Jul 2024 03:34:30 GMT

The Food and Beverage industry presents some unique challenges in the sealing world. FDA compliance and Clean-In-Place requirements can complicate seal design and potentially limit material selection. With these additional considerations, Food Industry seals often still must operate under the same strenuous conditions and performance specifics as many industrial or aerospace applications.

Things like pressure, temperature, and systems dynamics can create challenges for many standard seals. Many food production processes involve cooking or pasteurizing so high temperature performance requirements are often called for. Production line operations can demand seals capable of handling high-speed dynamics and extreme duty cycles.

Like many projects at Eclipse Engineering, a customer came to us after an off-the-shelf rubber seal was failing in their food product pump. With no simple solution in sight, they turned to Eclipse’s expertise to engineer a product that would meet their performance requirements while still complying to all food safety regulations and procedures.

The Customer’s Issue

The customer had developed a new device designed to dispense a condiment food product in a restaurant environment. The automated dispenser had to keep the product at a warm temperature and dispense a specific amount when used.

Operating Conditions:

Reciprocating Piston Seal
Stroke: 2”
Pressure: 200 PSI
Temperature: 180°F

The customer had originally chosen a typical FDA Elastomer U-Cup for the main piston seal. This inexpensive and off-the-shelf solution sealed well and performed satisfactory in their initial lab testing. But once employed in the field, some issues came to light.

During long periods of inactivity, the food product was somewhat solidifying in and around the seal. The sustained temperature was almost cooking the product into groove of the seal. Once this happened, the seal essentially lost all compliance in the material and geometry. Without any give, the friction between the bore and piston became great enough that the mechanics of the dispenser could no longer move the piston effectively. Thus, correct dispensing was not occurring.

During periods of sustained use, such as in their preliminary testing, the product had no time to solidify thus the issue was not initially detected. The unpredictable nature of the restaurant industry could mean days of heavy use, or days with almost no actuation at all. The seal needed to perform consistently in either case.

In addition to the main problem of frictional force being too great, concerns about cleaning procedures with the original seal also presented themselves. The solidified food product in the seal could become difficult to remove during the scheduled cleaning processes, creating a problem for the personnel and introducing a potentially insufficient sanitary condition.

The Eclipse Solution

Eclipse knew this would be a perfect application for a PTFE Spring Energized Seal, but one would need to be tailored to this specific application. Starting with the requirement that all seal materials would need to be FDA compliant, Eclipse chose its ET018: Mineral filled PTFE for the seal jacket. FDA compliance limits the potential use of many common PTFE fillers such as carbon and molybdenum disulfide. While Virgin PTFE and other unfilled materials are compliant, their wear resistance is not ideal in most dynamic situations. The Mineral filler greatly improves the mechanical properties and resilience of the PTFE, while still meeting the FDA requirement.

The coefficient of friction a PTFE based material can be roughly one tenth that of a typical rubber elastomer seal. So overall loading characteristics and motion of the piston will be far more consistent and fluid compared to the performance of the original seal, both in short term and long term use.

Turning to the spring, Eclipse chose its Stainless-Steel Cantilever V-Spring. The characteristic of the V-Spring lends itself to high point loading, which is ideal in reciprocating applications where viscous media needs to be scraped. This in conjunction with a scraper seal lip geometry provide optimum focus of the sealing force at the most critical point in the seal.

The V-Spring also facilitates the use of a critical feature applied in many FDA and food seals, a Silicone filled spring cavity. Filling the spring cavity with Silicone completely encapsulates the spring and essentially eliminates any grooves for product to become trapped.

Eclipse uses FDA compliant and NSF listed Silicone that’s available in various colors such as Clear, White, and Red.

Without the Silicone fill a V-Spring and groove would be very susceptible to media becoming trapped in the groove and potentially even behind the spring itself. This obviously would not be ideal for wash-down procedures. The Silicone fill means there are no cavities for entrapment and the seal has a continuous, smooth surface on all sides. Therefore, it is perfect for standard Clean-In-Place practices.

The relatively soft Silicone still allows the spring to operate and provide force in it’s designed direction, but care must be taken because it will contribute to the load characteristics of the seal. With friction a concern in this application, Eclipse made sure that the Silicone did not contribute any extra spring force by adjusting the PTFE jacket geometry and installed interference.

How It Performed

The customer was excited to test Eclipse’s new design in their application. Upon initial testing, they were impressed by the lower friction of the new PTFE material, which improved consistency of the piston movement. The true test came after long-term inactivity and there was a chance for the food product to solidify.

The customer was pleased to find that the force required to move the piston remained almost constant regardless of the amount of static time. The Silicone filled spring cavity prevented any product getting entrapped within the seal. This combined with Eclipse’s custom seal geometry ensured the piston always moved in a controlled and reliable motion and dispensed the required amount of product in all situations. The added ease of cleaning was a bonus feature that was an additional selling point for the customer.

Contact Eclipse today if a Silicone filled Spring Energized PTFE seal might benefit your food or FDA application >

Case Study: Eclipse Metallic Scrapers

doug@eclipseseal.com (Doug Montgomery) — Tue, 09 Jul 2024 03:12:19 GMT

Rod scrapers, wipers, and excluders are commonplace in the seal industry. Eclipse designs and manufactures these components on a regular basis. A wiper or scraper can be a critical part of keeping dust, dirt, and debris out of a hydraulic system. While a polymer scraper, such as a filled PTFE, can provide many years of low friction performance, some extreme applications need something much more robust and aggressive.

Eclipse was approached by a customer using a hydraulic cylinder in a metal foundry. The conditions presented a challenging environment for any seal component: intense heat and marring media. The cylinder was close enough to the molten metal to get slag deposits on the cylinder rod when fully extended.

Slag, a by-product of the smelting process, is often a mixture of metal and silicon oxides. The hard and abrasive properties of the slag were pushing conventional rod wipers and scrapers beyond their limits and allowing damaging contaminates into the hydraulic system. Frequent rebuilds and service delays where commonplace.

Eclipse was posed with a challenge to invent a scraping system that was up to the task.

Maximum Scraping Effectiveness

Polymer scrapers can be designed to withstand harsh environments. Dirt, rocks, and mud are usually effectively kept out of hydraulic systems by using polymer or plastic wipers. Eclipse’s EU000: UHMW-PE is an exceptionally tough polymer that can withstand tearing, impact, and abrasion in a wide variety of situations. But even UHMW would not be adequate for hardened slag. The abrasiveness combined with the intense, 500°F plus environment would effectively rule out the use of almost any polymer. Eclipse knew it had no choice but to fight fire with fire. A metallic scraper would be needed in this foundry application.

While metallic scraper rings are available in the market, the unique environment of the foundry also effectively excluded them from use. A typical metallic scraper uses a rubber or Nitrile element to both center the metallic scraping ring and allow for radial movement of the shaft. Using a metal scraper on a shaft without an element to allow for some “give” could result in high friction and damaging galling or marring of the cylinder shaft.

Often used in large industrial applications, shaft alignment and precision could be less than perfect. A hard-mounted metal scraper could easily damage the shaft if misalignment is present. A long axial scratch or gouge in the shaft would almost certainly cause leakage in the hydraulic system and be a costly repair.

But in an environment over 500°F, having a rubber element in the scraper would not be possible.

PTFE to the Rescue

With the extreme temperature ruling out the use of any rubber or elastomeric compound, Eclipse knew it would have to substitute a material for the centering and movement absorbing element used with the metal scraper ring. Eclipse chose its ET006: Carbon filled PTFE to fill this role. PTFE would be able to handle the intense heat but still be pliable enough to allow for misalignment and adequate centering. The addition of the Carbon filler further improves temperature capability and mechanical toughness. The slim jacket profile also works in minimal hardware space and allows for easy installation.

Eclipse’s chose to use a specific, unhardened grade of stainless steel for the metallic scraper. The unhardened stainless steel provides aggressive rod scraping while also reducing the risk of damaging the cylinder shaft.

Maximum Scraping

The combination of a stainless-steel scraping ring and a PTFE centering jacket proved to be an effective solution to the customer’s unique application. The high temperature capability of the PTFE meant a metallic scraping ring could be used without risk of severe damage to the cylinder shaft and thusly, maximum scraping effectiveness could be used.

The Eclipse Metallic Scraper ring efficiently removed any slag deposits from the shaft, ensuring the sensitive internal sealing components remained free of damaging contamination.

Eclipse Metallic Scrapers in Your Application

While a polymer scraper, wiper, or excluder might work for the vast majority of industry applications, extreme conditions might mean the next level of scraping aggressiveness could be necessary. A metallic scraping ring can withstand the harshest of media and could be essential in prolonging life of the sealing system.

While removing slag from a hydraulic cylinder shaft in a foundry is a perfect application for an Eclipse Metallic Scraper ring, a wide variety of situations could merit their use. Eclipse has specified metallic scrapers for use in applications of the other end of the temperature scale as well.

A particular customer was using a hydraulic cylinder on a bridge application where the cylinder location was prone to heavy icing conditions in the winter months. The metallic scraper effectively removed any ice from the shaft, while the PTFE jacket provided the benefits of having an indefinite shelf-life and no UV degradation. This meant extremely long service life and maintenance free operation for many years when compared to a scraper using rubber or Nitrile elements.

Another application well suited for an Eclipse Metallic Scraper was for a cylinder at a loading dock in a marina. The cylinder was to be actuated only a few times a year and was completely submerged in salt water. This meant the shaft was prone to barnacle and crustacean growth over the long periods of inactivity. A metallic scraper ensured the shaft was clean and free of contaminants when actuation was needed. The unique grade of stainless steel in combination with the degradation free properties of PTFE meant a long and effective service life of the scraper could be expected, even in salt water.

Contact Eclipse today to see if a Metallic Scraper Ring is right for your application >

Case Study: Replacing U-Cups with PTFE Spring Energized Seals in High-Temperature Applications

doug@eclipseseal.com (Doug Montgomery) — Sat, 01 Jun 2024 21:28:02 GMT

The use of elastomeric U-Cups in reciprocating sealing applications is widespread throughout the industry. As commodity items, U-Cups are readily available in a number of materials and can be found on-the-shelf from multiple distributors and manufacturers in many standard sizes.

Named for the shape of their cross-section, a U-Cup’s design is pressure energized, increasing sealing effectiveness when compared to a standard O-Ring. This means as pressure increases, the sealing lips are continually forced into the mating hardware surface ensuring good contact at all times. The simple and easily moldable design is an effective sealing solution to many systems in both hydraulic and pneumatic applications. Modifications in lip thickness and inclusion of an O-Ring Energizer can tailor sealing loads and wear life to specific situations.

A key advantage to an elastomeric U-Cup is the relatively small and simple hardware space needed. Because of their flexible compounds, most U-Cups can be installed in a solid gland configuration. Therefore, a basic ID or OD groove is all that is needed for proper seal retention and no special tools or considerations need to be taken for correct installation.

U-Cups are available in many of the same compounds as standard O-Rings such as Nitrile, Fluorocarbon, and EPDM, but polyurethanes might be the most common material. Urethane provides a good combination of elasticity/pliability and toughness. Therefore, it exhibits good sealing characteristics as well as durability and wear resistance.

These desirable qualities make U-Cups an optimal solution for many sealing systems across multiple industries and can be found in countless standard products. But Eclipse is approached many times a year with customers pushing the limits of standard U-Cups and in need of better solutions.

The Client’s Issue

Eclipse was approached by a leading pneumatic cylinder manufacturing seeking a sealing solution for a unique application. While U-Cups typically provide optimal sealing performance in pneumatic cylinders, this application presented a difficult challenge. The air cylinder was to be used as an actuator for a latch on a large industrial oven. While pressures, speeds, and cycle times were nothing out of the ordinary, the temperature at which it had to operate at was – a continuous 500°F.

Operating Conditions:

Pressure: 90 PSI
Media: Air
Stroke: 3”
Cycle Frequency: 2-4 cycles/day
Cylinder Rod Ø: 0.500”
Operating Temperature: 500°F

The most common Urethane U-Cup seals have a maximum temperature rating of only 220°F, so they knew these wasn’t a viable choice. Their best option was a Fluorocarbon U-Cup, which are typically rated up to 400°F. Fluorocarbon can withstand temperatures up to 440°F but only for short periods of time. Despite not meeting the temperature requirements of 500°F, the customer gave these a try. Not surprisingly, though, the seals failed quickly.

The real challenge was the fact the oven operated at a continuous 500°F for long periods of time. Even if the properties of the Fluorocarbon could remain intact enough to provide an acceptable level of sealing, the longevity of the seal would be severely compromised. Like most rubber compounds, Fluorocarbon is subject to “heat aging” where high temperatures accelerate the degradation process that normally occurs over years of service. At this extreme temperature, the effect would be prompt. The customer quickly concluded a standard sealing solution wasn’t going to work and turned to Eclipse.

The Eclipse Solution

Eclipse knew that 500°F called for a PTFE based seal material. Depending on fillers, PTFE can successfully operate at temperatures as high as 575°F. The long-term exposure to high heat would also not be a problem for PTFE. Unlike rubber or elastomeric compounds, PTFE will not degrade over time and can be considered to have indefinite shelf-life.

With the temperature ruling out the use of O-Ring energizers, Eclipse’s Spring Energized seals would be needed. For optimal point loading in a reciprocating application, Eclipse chose a stainless steel Cantilever V-Spring for the energizer and ET006: Carbon filled PTFE as the seal jacket material. The carbon filler provides excellent heat and wear resistance while remaining commonly available.

Eclipse designs and manufactures thousands of spring energized seals every year, many of them successfully operating in conditions far more difficult than the parameters presented here. The challenge for this application was the packaging and installation requirements mandated by the customer. The simple solid groove housing, in which a standard U-Cup installs without trouble, would not work for a PTFE spring energized seal.

For rod configurations, installation into a solid gland requires the seal to be “kidney beaned” or folded in on itself to be put into the groove. For an elastomeric U-Cup, this is no problem as it can be bent and distorted and still spring back into its original shape once in the groove. For piston configurations, the seal needs to be significantly stretched for installation into the groove. Again, this is not a problem for rubber or urethane compounds.

But the combination of PTFE’s inelastic nature and the fact that a cantilever spring cannot be severely distorted without damage or yielding, means installation of PTFE spring energized seals into solid glands is normally not an option. At very large diameters, with comparable small seal cross-sections, installation might be achievable. But at diameters less than an inch, such as in this case, installation would be nothing short of impossible without seal damage.

The customer’s ideal solution would have retrofitted into the current U-Cup grooves, but with this not being feasible, Eclipse needed to propose an acceptable alternative. Most spring energized seals at smaller diameters are installed in split or two-piece grooves. This configuration is an open groove with a secondary retention piece. For example, the seal can be contained by a separate bolted on cover-plate or threaded packing nut.

The two-piece design facilitates easy installation and replacement for spring energized seals, but the customer did not want to significantly change the current hardware design for the cylinder. Adding a cover plate to the assembly would be out of the question. Eclipse had to work within the current hardware envelop of a standard air cylinder and present a design that allowed for easy installation of the spring energized seal without adding any components.

Eclipse knew this was the perfect application to use a stepped gland configuration. A stepped gland is an open groove with a small barb or step at the front which retains the seal. A specific seal lip type ensures the seal gets locked into place once pushed over the step. In this case, a step of only 0.010 to 0.015” is all that is needed for seal retention. The seal needs to be only minimally compressed or stretched (depending on rod or piston configuration) for a simple “push in” installation.

Most customers are surprised such a small feature can retain the seal fully. In most cases, once installed, the seal is so well locked in place that special tools or physically damaging the seal will be required to remove it. Stepped glands are successfully employed at a variety of diameters in the most challenging reciprocating applications.

How It Performed

Eclipse’s PTFE Spring Energized Seal ensured the air cylinder performed flawlessly at the 500°F temperature. Eclipse’s ET006: Carbon filled PTFE seal jacket provides excellent wear resistance and extended seal life even in the long-term high temperature environment. The improved low friction characteristics of PTFE also added to the smooth and consistent cylinder operation unlike an elastomeric compound.

The use of a stepped gland allowed the use of the spring energized seal without significant modification to the customer’s hardware and no additional components. Eclipse successfully designed and manufactured a sealing solution that met or exceeded the customer’s requirements in every way.

Eclipse has successfully converted many U-Cup seals configurations to use PTFE Spring Energized Seals in a diverse number of industries and applications. Whether due to extreme temperature, chemical attack, severely abrasive media, or better friction control, if you have a standard U-Cup that is failing in your application — Eclipse can help.

Celebrating 25 Years of Innovation & Growth: The Eclipse Engineering Journey

doug@eclipseseal.com (Doug Montgomery) — Thu, 30 May 2024 19:28:50 GMT

Humble Beginnings

In 1999, Eclipse Engineering’s founder, Cliff Goldstein, recognized an industry need for engineering support in the manufacturing and prototyping services sector. Eclipse was born with the goal of offering unparalleled service and custom engineered solutions for demanding applications.

Looking back 25 years, Eclipse Engineering started as a one-room schoolhouse. Cliff would spend mornings prospecting for business, afternoons working on CAD designs, and evenings machining parts. It was a family-run startup, with his wife Bobbi handling invoicing and bill payments, and even his mother labeling parts when she was around.

Growth and Expansion

After about six months, the business had grown enough to hire additional help. This was when the business really took off. Support from major national seal distributors played an instrumental role in getting the business off the ground. Thanks to local customers from Jemco Seal, Eclipse was on the move.

Initially, the goal was to run a basic plastics machine shop, with no intention of entering the seal market. However, inquiries started pouring in for seal manufacturing due to Eclipse’s engineering support, plastics machining expertise, and quick turnaround on parts. After about two years, Eclipse acquired all the seal business from Jemco Seal, along with their inventory, effectively establishing Eclipse as a seal distributor. This move complemented the fledgling distribution business that Eclipse had started independently.

A Major Milestone

Eclipse secured a major contract with Sundyne Pumps in Colorado, which launched the company into high gear. Over the years, Eclipse evolved to produce standard product offerings for a wide range of industries including Hydraulics, Pneumatics, Energy Production, Aerospace, Pharmacopeia, and Food Handling. The institution of the ISO9001/AS9100 quality system in 2015 allowed Eclipse to become a top-tier supplier.

Empowering Employees

Fast-forward 25 years, and Eclipse has expanded from a few pieces of equipment to seven CNC turning centers, a CNC mill, two laser welders, visual measurement machines and all the support equipment for a modern design and machining center. Our expert sales and engineering teams help design and produce sealing solutions for customers down the street to across the globe.

With 25 employees, five years ago, an ESOP (Employee Stock Ownership Plan) was created. This plan empowered the employees who had been with Eclipse since the beginning—they now own a stake in Eclipse and can shape their own destiny. For our customers, this business continuity means our culture of quick responsiveness to their needs remains unchanged.

Customer-Centric Approach

Eclipse Engineering was founded on the concept that if the company placed its customers’ needs above its own, it would always profitably grow. This customer-centric approach has remained steadfast, even in the face of Covid and the challenges of a global economy. Eclipse has continually adapted to evolving customer requirements including the increasing need for quality certifications and regulatory compliance.

Looking Ahead

Today, Eclipse is a reliable supplier of polymer-style seals and bearings in the global marketplace. It’s the synergy between the employees and customers that has propelled Eclipse into the company it is today. As Eclipse celebrates its 25th anniversary, it looks forward to continuing its legacy of innovation, growth, and exceptional customer service.

Case Study: Customized Seal Load/Friction in a Torque Sensitive Rotary Union

doug@eclipseseal.com (Doug Montgomery) — Fri, 03 May 2024 03:25:52 GMT

Rotary Unions are mechanical devices meant to allow the transfer of liquid or gas media from a stationary input to an output that is rotating. Rotary Unions are found in industries across the board, from compact units in hi-tech robotics to large industrial hydraulic units for construction equipment.

A classic example of where a rotary union is found would be in large hydraulic excavators or backhoes. The union permits hydraulic fluid to be transferred to the track drive system while allowing the cab and excavator arm to pivot 360° about the base.

A more modern application would be in large, electricity generating wind turbines. A rotary union allows hydraulic fluid to pass from the stationary base into the spinning blade pitch control mechanism. Thus, the pitch of the blade can be optimized for all wind conditions while in constant motion.

Other industries including aerospace, semi-conductor and medical require smaller more precise units to transfer gases or cooling fluids. As automation in these sectors becomes more prevalent, unions used in robotic control and movement are continually evolving.

When boundaries are progressively pushed, sealing solutions also need to rise to the occasion. Eclipse is here to accept these challenges and be an integral part of the continual development of future technologies.

The Client’s Issue

Eclipse was approached by a semi-conductor manufacturer looking for seals to be used in a rotary union. The union would be employed in their newly developed wafer processing equipment that would operate in a clean room environment. With stringent seal life and frictional requirements, the customer knew no standard or off-the-shelf seal would be suitable. A custom designed and manufactured seal from Eclipse would most definitely be in order.

Operating Conditions:

Rotary Rod Seal
Rod Diameter: Ø2.500
RPM: 190
Duty Cycle: 15 seconds on, 15 seconds off
Media: Air
Pressure: 100 PSI
Temperature: 70°F
System Breakout Torque @ 100 PSI: less than 12 ft-lbs
Seal Life Requirement: 20,000 Hours (running)

The challenging the aspects of the application would be the low friction requirements of the seals combined with the needed extended service life. The unit would be operating in a clean room environment, therefore very specific electric motors and drive units must be used.

Any particle generation for the motors must be carefully controlled in order to meet the clean room standard. Even particulate generated from cables rubbing together could be enough to contaminate the environment, so packaging and containment of the driving mechanisms would be extremely important.

This therefore means simply specifying a larger or more powerful motor to account for friction in the rotary union would not be possible. The strict containment of the units means serviceability of the mechanisms and seals would be limited and costly, thus the need for longest seal life possible.

The customer’s aim was to utilize a relatively large four input/output rotary union. In order to achieve this, five internal seals would need to be used to seal the ports correctly. With each seal compounding the friction of the system, this provided an additional challenge to the seal design.

The Eclipse Solution

Eclipse makes thousands of rotary seal rings every year, many of which find their way into rotary unions of all types. As part of Eclipse’s standard seal offering [Link to https://eclipseseal.com/products/o-ring-energized-seals/rotary-seal-ring/ ], this type of seal was designed specifically for these type of applications.

A rotary seal ring works best in higher pressure, slower speed conditions. This is typically opposite of rotary lip seals, which operate at high surface speeds and little or no pressure. Eclipse’s standard rotary seal rings are designed with high pressure hydraulics in mind. But a seal with enough robustness to withstand a 5,000 PSI hydraulic system in a piece heavy construction equipment is not what was needed in this compact and sensitive application.

All of Eclipse’s seals, whether a standard catalog item or not, are made to order. Therefore, there is no penalty in lead-time for fully customizing and tailoring a seal to meet the customer’s sealing goals. So, while the catalog rotary seal ring would be a great starting point, Eclipse knew modifications would be necessary to meet the friction and torque target.

As suspected, Eclipse’s theoretical friction calculations and estimates revealed that a standard rotary seal ring design would indeed require too much torque to turn the rotary union with the customer’s current motor outputs.

At relatively low pressures, such as in this case, the O-Ring energizing the seal still has significant influence on the loading of the seal. Eclipse turned its attention to reducing the O-Ring compression and subsequent load to reduce the friction of the system. This could be achieved by two methods: reducing the radial wall of the seal ring or expanding the groove depth in which the seal operates. Both methods would reduce the amount of squeeze on the O-Ring and therefore the load translated into the seal.

But with limited hardware space available, Eclipse did not have room to deepen the grooves. There would be no choice but to reduce the actual seal cross-section. This would be a delicate balancing act though. Thinning out the seal would also decrease the amount of physical material that can be worn away. A thinner seal will have less wear life than one of standard thickness. Of course, wear life was one of the customer’s specific goals.

A possible third option of using lower durometer O-Rings to reduce load was also ruled out. The customer was concerned with the possibility of a future requirement to use specialty compound O-Rings in the system. These O-Rings can be much more limited in the available durometers. Consequently, Eclipse needed to design around the standard 70 durometer O-Ring hardness.

How It Performed

Eclipse’s years of seal design experience allowed them to strike the perfect balance of sealing friction and wear life. Eclipse’s in-depth friction and wear life estimation tools resulted in a carefully controlled radial seal wall dimension. This reduced O-Ring loading enough to decrease the combined friction of the system enough to meet the customer’s targeted breakout torque requirement.

Eclipse chose its ET012: Fiberglass/MoS2 filled PTFE for the seal rings. ET012’s combination of toughness from the Fiberglass and internal lubricity from the MoS2 contributed to the success of the system. While still being relatively thin walled to reduce friction, Eclipse’s design was able to meet the wear life requirement as well. The customer was pleased to incorporate Eclipse’s low friction and long-life design in their system.

Contact Eclipse today if a custom engineered Rotary Seal Ring could be right for your application.

The Challenges of Rotary Sealing

doug@eclipseseal.com (Doug Montgomery) — Sat, 02 Mar 2024 03:52:08 GMT

Eclipse serves a highly diversified customer base from almost every sector of industry. From medical to mining, aerospace to deep-sea, each application presents its own unique set of challenges and hurdles to overcome.

Seal applications are typically classified by the type of dynamic motion the seal is experiencing. The general categories are rotary, reciprocating, and static. While each category can lend itself to difficult sealing conditions and stringent goals, we’ll see that rotary applications often present some of the most challenging set of circumstances for a successful sealing solution.

Static vs. Reciprocating vs. Rotary

In the world of seal applications, static seals have it relatively easy compared to their dynamic counterparts. With no relative motion, there is nothing to wear out. And without friction being a concern, the seals can be much more heavily loaded, promoting better sealing. That’s not to say that a static application can’t be challenging. Eclipse sees many high-pressure gas sealing applications at cryogenic temperatures. While being static, these seal designs are not trivial, often requiring special materials and finishes.

Reciprocating applications add linear motion to the mix. Classic reciprocating sealing application would be a hydraulic cylinder found in everything from bulldozers to factory presses. Reciprocating applications typically consist of a piston and rod configuration requiring seals in both places. Media can be anything from hydraulic oil to air, abrasive epoxies to food products. Seals need to withstand the wear, friction, and media impingement created by the dynamic motion.

In most cases, rotary seal applications involve sealing on a spinning shaft or rod. There are rotary configurations where a stationary seal is sealing against a rotating bore, but these are less common. There are few rotary applications that don’t require any sealing elements. Even if the equipment/machinery does not contain pressurized media, seals are still likely needed to retain bearing lubrication or exclude outside dust or debris.

The Added Difficulty of Rotary

High Pressure-Velocity

PV or Pressure-Velocity is a quick metric to determine the strain on a seal in a dynamic application. A full article explaining PV can be found here: What You Should Know About Pressure-Velocity (PV) . In short, the speed and pressure of a system will combine to accelerate the wear of a seal.

Rotary distinguishes itself from reciprocating applications by its relatively easy means of creating high surface speeds and a resultant high PV. A simple electric motor can turn a shaft greater than 10,000 rpm, while it would take heavy machinery to create a high frequency, long stroke reciprocating motion at the same surface speed.

While there are few applications that require high speed, long stroke reciprocating motion, the number of industries requiring high-speed rotary seals is large and increasing. The progressive electrification of automobiles is an example. With high torque motors spinning upwards of 20,000 rpm, with no internal lubrication, seals for electric car motors present a sizable challenge for seals.

Shaft Runout

Along with high-speed rotary comes the inevitable problem of shaft runout. Runout is a mechanical specification that dictates how much a shaft can deviate from true circular motion. In essence, it can be thought of as how eccentric a shaft is moving. Some amount of runout is present in any mechanical system. The severity is dictated by component tolerance control and bearing arrangements.

Runout becomes a major problem for rotary seals as speeds increase. The seal is being asked to conform to a moving, non-circular shape as the shaft rotates around. At a certain speed, the lip will not react fast enough to stay in full contact with the shaft and leakage will occur. Seal wear will greatly be accelerated in high runout applications.

The addition of spring energizers is often mandatory if runout is excessive to help keep the lip in contact with the shaft. This adds cost, increases friction and heat build-up, and ultimately reduces the wear life potential of the seal.

Runout is something that reciprocating applications obviously won’t have to deal with.

Anti-Rotation Requirements

Another additional aspect rotary seals must contend with is the need for an anti-rotation element. While in many cases, reciprocating seals can essentially be “drop in” as far as seal installation, rotary seals need further gland considerations.

Especially at high speed, seals need to be secured on the non-dynamic side to ensure the seal does not start rotating in the gland. Seal failure will quickly occur if this happens as the seal will be wearing on surfaces not meant for dynamic motion and in an uncontrolled manner.

There are a number of means to provide anti-rotation. At lower surface speeds, an O-Ring interface on the static side of the seal can be sufficient. Seals such as Rotary Seal Rings and O-Ring OD Lip Seals utilize this functionality. This design works based on the fact that the coefficient of friction between the O-Ring and hardware will be much higher than the polymer seal and dynamic surface.

A Flanged Spring Energized Seal accomplishes anti-rotation by physically clamping the flange of the seal in the hardware. This configuration ensures positive anti-rotation, helps in static side sealing, and facilitates easy seal installation and replacement. The downside is multiple hardware components and relatively complicated and detailed groove design.

At higher surface speeds, seals are typically a Cased Lip Seal design. This design counts on a press fit of a metallic outer cased in the hardware to ensure anti-rotation. Much like standard oil seals, the press fit allows use of the seals in an open gland without a need for addition methods of seal retention.

Single-Point Wear and Loading

The last unique challenge of rotary sealing is the fact that wear is focused on a single point on dynamic sealing surface. Unlike a reciprocating application where the seal is riding against the whole length of the rod or bore during the stroke, a rotary seal will be wearing on one point of the hardware for the life of the seal.

This combined with the possibility of very high surface speeds lead to accelerated wear of both seal and hardware. To combat seal wear in highspeed rotary applications, Eclipse has numerous filled PTFE blends designed with extending wear life specifically in mind.

ET019 and EZ032 are high fill blends intended for the most demanding wear conditions, whether it be abrasive media or high PV rotary. These blends require a fully hardened (55+HRC) dynamic surface otherwise they will quickly deteriorate hardware.

Single-Point loading also creates the problem of localized heat generation. Friction from the seal acting on a small area can lead to significant heat buildup. This is unlike reciprocating applications where the seal is acting on a different point of the hardware over the course of the stroke. This distributes the heat due to friction and gives each point time to cool between cycles.

A seal material such as UHMW-PE can work fantastic in a reciprocating application but is almost never used in rotary because localized heating can push it beyond its upper temperature limit. Adding in system ambient heat can limit the seal material options to high temperature PTFE blends.

Conclusion

Out of all the various seal applications and sealing configurations Eclipse designs and manufactures solutions for, rotary is often the most challenging. It presents some unique conditions where only specialized seals are up to the task. Many Eclipse projects have started with someone first trying O-Rings or off-the-shelf seals in a rotary application only to find immediate problems.

Eclipse is here with decades of experience in rotary applications of all types to design and manufacture a sealing solution to your challenging project.

Seal Terminology 101: Getting Started in the World of Seals

Mon, 03 Oct 2022 20:02:00 GMT

While the average person can probably recognize a rubber O-Ring , knowledge of advanced sealing devices remains a largely obscure field of knowledge. Eclipse is here to be the subject matter experts and guide you to the best sealing solution, but being familiar with some basic seal terminology will aid us in the process.

The ability to effectively communicate the operating conditions and goals of the sealing system will expedite the design and quoting process and ensure that we choose the optimal solution for you.

Below we’ll discuss some common terms and industry nomenclature to get you started in the world of seals.

O-Rings, Gaskets, Spring Seals, Cap Seals – What do I Call These Things?

Sometimes just finding what to call a particular seal can be a challenge in and of itself. We’ve had customers contact us looking for a new “O-Ring” or “gasket” when they actually have a PTFE Canted Coil Spring Energized Seal in front of them.

In many cases, terms like “O-Ring” are used to generically describe any kind of seal regardless of type or functionality.

Other customers who primarily work with metallic or ceramic sealing elements like piston rings or mechanical face seals, might refer to any other type of seal as a “soft seal,” even if it’s made from a highly filled PTFE. Another customer might request an “oil seal” even though their application is a dry-running rotary vacuum arrangement.

Eclipse understands just describing the seal needed can be a major barrier. That’s why we designed our standard part number catalogs to be graphically based to help with product recognition and description.

While the catalogs are meant to demonstrate Eclipse’s capabilities and standard part number schemes, they’re also great tools for communicating seal types and configurations.

Explore our many products >

Grooves and Glands

The physical space for a seal to occupy is often simply called a groove but can also be referred to as a gland. In most cases, it’s a rectangular groove cut into the hardware whether it be on a piston, in the housing for a rod, or in the face of two mating surfaces.

In contrast to O-Rings and elastomeric seals, PTFE and polymer seals are critically dependent on hardware conditions for proper functionality. Configuring the gland for proper seal installation and preparing the mating surfaces with the necessary finishes and hardness is necessary for successful sealing.

Learn more about the different types of seal glands here >

Diameters

OD – Outside Diameter

ID – Inside Diameter

Almost all the polymer seals we manufacture are round parts machined on CNC lathes. Therefore, the diameters are key dimensions for both the seal and mating hardware.

Diameter dimensions are proceeded by the symbol “ Ø ” on manufacturing prints. Many seal prints feature cross-sectional views where the diameters are not shown completely. This leads to some confusion about whether the radius or diameter is being called out.

A radius would be proceeded by the symbol “ R ” and would involve finding the theoretical center of a part to measure/inspect. Therefore, diameters are almost exclusively used to describe the external dimensions of parts.

With that being said, the diameters of thin, flexible parts can be very challenging to measure at times. Tools such as a Visual Measurement Machine, which provides a non-contact method that also takes into account the inevitable part out-of-roundness, can be invaluable for accurate inspection.

The diameters of PTFE and polymer seals are also typically the most difficult dimensions to tightly control while machining, especially at larger sizes. This is due to the inherent instability of polymer materials. Fortunately, most seals are not critically dependent on diameter precision for functionality.

Radial Cross-Section

The radial cross-section of a seal sometimes referred to as the “wall” is equal to the OD minus the ID, divided by two. The radial cross-section is often the most critical dimension for the functionality of a seal. This dimension will determine the compression or squeeze on a spring or O-Ring energizer which is responsible for providing the contact and sealing force of the seal.

Too little or too much compression or interference can cause a number of problems from leakage to excessive wear. Thankfully, the cross-section dimension is typically easy to hold within tight machine tolerances and easy to inspect.

Seal Width or Height

The axial length of the seal can be referred to as either the seal width or seal height. Eclipse typically uses width rather than height because this dimension is most often checked with calipers while holding the seal in your hands, rather than with a height gauge on a calibrated flat surface.

The seal width will always be dimensioned to have clearance in the hardware gland, but how much clearance can be important. In reciprocating applications, a seal too undersized for the groove can shuttle back and forth in the gland causing accelerated wear.

This also creates an opportunity for the seal to become cocked or misaligned in the groove which can lead to premature failure.

Rod and Piston Seals

The majority of the seals Eclipse produces fall under the category of a rod or piston seal. A piston seal typically seals the inside diameter of a cylinder or bore, meaning the outside diameter of the seal is the sealing surface. A rod seal is typically sealing on the outside diameter of a shaft, thus the inside diameter of the seal is the sealing surface.

While this is straightforward most of the time, things are not always as clear. Many HPLC (High-performance liquid chromatography) and other lab testing equipment applications use ceramic shafts that act as reciprocating pistons. So, while they may need a seal for a piston, the product will in reality be a rod seal.

To avoid confusion, we usually differentiate rod and piston seals based on the dynamic sealing surface. If the OD of the seal is dynamic, it’s a piston seal. If the ID of a seal is the dynamic surface, it’s a rod seal.

Some seal types, like most cantilever spring seals, are symmetrical in design and can be used for either application. Other seals, like Canted Coil Spring seals, have different geometries based on whether the OD or ID is the primary sealing surface.

This is to provide optimum loading and wear characteristics to extend seal life and enhance sealability.

E-Gap

E-Gap is short for extrusion gap and is defined as the clearance between the hardware components. In a piston configuration, this would be the clearance between the piston and bore. In a rod configuration, this is the clearance between the rod and the housing it’s passing through.

In short, it is the physical gap that needs to be sealed in the hardware. It is one of the primary factors in the pressure handling capability of a seal. Seals improperly designed for a particular extrusion gap will cold-flow or extrude through this opening at high pressures.

If you’re wondering how much pressure a seal can hold, the E-Gap will likely be our first indicator.

Learn more about E-Gaps in this article >

PV – Pressure Velocity

The PV of a sealing system is the pressure multiplied by the surface speed of the dynamic seal interface.

PV is used as a quick gauge of the plausibility of the success of a sealing system in a given application. The exact value itself is not of tremendous importance, but it provides a relative idea of the stress and projected wear life of a seal.

Learn more about PV >

Trade Names and Acronyms Galore

Polytetrafluoroethylene doesn’t exactly roll off the tongue. How about Polyether Ether Ketone? Anyone need some Ultra High Molecular Weight Polyethylene?

Many of the seal materials Eclipses uses on a daily basis are commonly known and referred to simply by their acronyms (PTFE, PEEK, UHMW) rather than the full chemical names.

Other seal materials are commonly known by trade or brand names, not unlike consumer products like soft drinks or generic prescription drugs. Fluorocarbon (FKM) O-rings for example, are usually called trade name Viton® even if a generic compound is being used.

Teflon®, the first and most common trade name for PTFE is a household term thanks to non-stick frying pans. Yes, this is the same PTFE used to make seals and the low friction and high heat capabilities are a benefit in many sealing applications.

Blended PTFE seal materials can get even more convoluted with multiple fillers having trade or generic names which may or may not be used. Most seal companies also assign their own material codes even if the blend of PTFE is common throughout the industry.

Don’t worry if you’re not a chemist, we’re here to decipher the alphabet soup and provide the best material for your application.

Read our break-down of the most common seal materials >

Case Study: Sealing 15,000 PSI at 300°F With a Large Extrusion Gap

Wed, 10 Aug 2022 18:19:00 GMT

Eclipse serves dozens of industries and provides sealing solutions for applications on, off, and below the surface of the planet.

Each application has its own set of challenges whether it be manned space flight, surgical medical instruments, or high-volume automotive components.

One industry that continually presents Eclipse with challenging sealing conditions is oil and gas. In many instances, operating in the extremes of pressure, temperature, and caustic or abrasive materials are all required. Down-hole drilling processes in particular can present some of the most demanding environments or situations for seals.

Eclipse provided spring-energized seals for a customer who manufactures sensitive down-hole drilling instrumentation. The seals were working great under their initial design parameters, but that soon changed when a new worst-case, disaster scenario came up.

Follow how Eclipse addressed the problem and discovered a new solution to optimizing sealing performance, even when operating under extreme conditions.

The Client’s Issue

The seals and hardware Eclipse provided were designed around the maximum operating pressure of 500 psi. This pressure is relatively mild for a standard spring energized seal, so Eclipse biased the design around fine-tuning sealing performance.

Problems arose when the customer landed a new deep sea drilling contract and wanted to be sure the instrumentation would be protected in a worst-case situation — if every high-pressure external seal failed at the bottom of the deepest part of the ocean. The water pressure at this depth would be 15,000 psi — 30 times what the instrument seals were designed for.

To make matters more challenging, the customer wanted the seals to withstand this pressure at the highest possible temperature the instrument could see — 300°F.

Operating Conditions:

The customer tested the seals at the new pressure and found they performed exceptionally well at low and ambient temperatures, despite being designed for a maximum of 3,000 psi.

The seals eventually failed at the maximum temperature due to the seal softening and allowing extensive extrusion .

The Challenge

Eclipse has utilized successful sealing solutions at pressures above 30,000 psi, but these configurations are heavily dependent on identifying hardware specifications, namely the extrusion gap (the space or clearance between the hardware surfaces that need to be sealed).

Extreme pressures can start deforming the seal and pushing it through the gap, in other words, extruding the seal. Once the seal is deformed enough, the structural integrity of the seal will be compromised and leakage will occur.

Elevated temperatures can further impact the durability of the seal. As temperatures increase the heat will inevitably soften the seal material making it easier to extrude.

The customer’s hardware was designed around the initial 500 psi and ambient temperature requirements. This unfortunately meant the specified extrusion gap was far larger than what would be needed for 15,000 psi and 300°F.

Eclipse is no stranger to high-pressure applications and has many options to bolster seal design. Increasing lip thickness and extending the seal heel length are common high-pressure handling modifications. But these designs all require additional physical space for the seal to occupy.

The hurdle to overcome was presented when it became evident that the customer’s hardware was already in production. No changes to the hardware could be made.

Eclipse decided we’d have to design a seal to handle the 30X pressure increase within the confines of the original envelope.

The Eclipse Solution

Eclipse knew it would need to get creative to handle the pressure without physically increasing the size of the seal. The first step would be to switch the jacket material to a blend with a higher filler content.

The original seals were ET014: Polyimide filled PTFE . Eclipse stepped up to ET025, which is also Polyimide filled PTFE, but at a much higher fill percentage.

The additional Polyimide significantly increases the extrusion resistance but still maintains the desirable sealability characteristics the customer was expecting. But a simple material change alone would not be enough to meet the pressure handling requirements.

Eclipse simplified the seal geometry to allow for thicker lips on the jacket and make room for a small wedge-style back-up ring. Back-up rings are often critical accompaniments to seals when pressures get extreme. They effectively decrease the size of extrusion gaps.

The Impact of the Back-Up Ring

By adding the back-up ring to the rear corner of the seal, the gland width wouldn’t have to be expanded, which is usually the case with these types of rings.

Eclipse chose its EP033: Virgin PEEK for the back-up ring material. PEEK is a much higher modulus or stiffer material than PTFE. Consequently, it is much more difficult to extrude.

While PEEK has a high upper-temperature limit, it also retains the non-galling and flexibility attributes of plastic. There’s no risk of damaging the hardware, unline a metallic back-up ring.

The wedge shape of the back-up ring also contributes to the increased pressure handling of the seal. The wedge is angled so that as pressure forces the seal to the back of the gland, the heel rides up on the back-up ring keeping it away from the extrusion gap.

How it Performed

With higher filled jacket material and the back-up ring effectively minimizing the extrusion gap, the seals passed the 15,000 psi at 300°F worse-case sealing test.

The customer could now safely market their instrumentation as prepared to handle any drilling situation in any location.

This was all done without any changes to the hardware, saving the customer from an extremely costly redesign and rework. It’s also important to note, Eclipse achieved the higher-pressure rating without compromising the sealing performance at the lower operating temperatures.

Whether your next instrumentation requires seals that can withstand extreme pressures or elevated temperatures (or a combination of both), Eclipse can help find a solution that will exceed your expectations.

7 Best Fillers That Improve PTFE’s Performance

Thu, 30 Jun 2022 02:18:00 GMT

PTFE was discovered in the 1930s as an accidental byproduct of chlorofluorocarbon refrigerant production. It’s a synthetic compound consisting wholly of carbon and fluorine — a fluorocarbon.

Its many unique properties make it highly attractive as a seal material. It possesses one of the lowest friction coefficients of any known material, is nearly 100% chemically inert, and can be used in temperatures from deep cryogenics to almost 600°F.

While all these characteristics are impressive, there are some aspects of Virgin PTFE that leave something to be desired. Things like wear and creep resistance could use an improvement when used in dynamic applications. Thankfully, PTFE is easily blended with other compounds to improve performance quite drastically in these areas, as well as other specific properties.

Eclipse has over 50 unique PTFE blends to choose from. Eclipse’s engineers and knowledgeable sales staff are here to guide and recommend the highest-performing seal material based on the goals of the application.

Below we’ll highlight a few of Eclipse’s favorite PTFE blends and what applications they’re best suited to.

ET002: MoS 2 filled PTFE

With the addition of a small amount of Molybdenum Disulfide (MoS ₂ ), ET002 allows for better performance in friction-sensitive applications when compared to Virgin PTFE.

MoS ₂ is a commonly blended solid or particulate lubricant used to make materials “self-lubricating.” ET002 is best suited for dry running applications where minimizing and maintaining predictable friction is paramount.

Industries like semiconductor production and precision robotics benefit from the extremely low and consistent friction characteristics of ET002 seals.

ET006: Carbon-filled PTFE

The addition of carbon particle filler classifies ET006 as a medium-level filled PTFE. As a particle filler, carbon homogeneously disperses in the PTFE matrix imparting wear resistance while still maintaining the majority of the virgin resin flexibility.

These properties are extremely useful when considering an upgrade from low fill material with minimal compromise in sealing efficiency. As an all-around performer in reciprocating and rotary applications, ET006 is a good starting point when specifying a seal material that offers high-value performance.

ET013: Fiberglass / MoS 2 filled PTFE

When hardened dynamic surfaces are available, ET013 offers extended wear life over lower filled compounds. Glass short fibers reinforce the PTFE matrix imparting wear resistance, extrusion resistance, and improved high-temperature performance.

ET013 is often utilized in high-speed rotary applications like engine and gear pump shaft seals. In these applications, hardened dynamic surfaces of 65 Rockwell C minimum are required.

It’s best used in lubricated service but is capable of running dry due to the additional MoS ₂ solid lubricant. ET013 is used in reciprocating applications where high-pressure velocities are present and is a good choice for buffer ring seals and other pressure knock-down devices.

When used in conjunction with one of the available Eclipse spring energizers , this material makes an excellent high-temperature seal as well as an aggressive scraper up to temperatures of 575°F (302°C).

ET014: Polyimide-filled PTFE

In most basic terms, ET014 is “plastic-filled plastic.” The Polyimide filler is a high-performance polymer with excellent heat resistance and mechanical properties.

While significantly improving the wear resistance and physical properties of the PTFE, this blend still retains the non-abrasive nature of plastic. Because of this, ET014 is the first choice for dynamic sealing applications using unhardened hardware components.

ET014 is also FDA Compliant which also makes it a good option for food and medical products which often utilize stainless steel hardware with limited hardness potential.

EZ032: Carbon/Carbon Fiber-filled Modified PTFE

If wear resistance and overall toughness are the name of the game, EZ032 is one of Eclipse’s go-to materials. Proprietary blending technology is used to evenly disperse carbon and fiber fillers throughout the base resin imparting wear resistance and high-temperature capabilities.

As an example, EZ032 is being used as wear rings at 575°F (302°C) continuous operating temperature. What makes EZ032 a unique material is how the resin blending allows for a high level of fillers to be added without degrading the properties of the base resin.

Typically, higher-filled resins don’t lend themselves to being used in seals. In the case of EZ032, the desired properties of pliability and resiliency still remain — making this material useful in critical sealing applications where high-pressure velocities are present.

EZ032 is a common upgrade for rotary applications where filled PTFE materials (glass, carbon, PPS) are often specified for wear life. In those applications, EZ032 offers additional seal life with equivalent or better sealing efficiency.

Running on hardened surfaces, EZ032 makes an excellent choice for gear pump seals, mechanical face seal elements, and downhole seals.

Not to be Overlooked, ET000: Virgin PTFE and EZ030: Virgin Modified PTFE

While fillers in general greatly increase many attributes of PTFE, there are some applications where virgin or unfilled grades will perform best. These are usually static applications that will benefit from a seal with maximum compliance and elongation.

Virgin grades are almost exclusively used in static cryogenic applications where maintaining pliability at extremely cold temperatures is key for sealing performance.

Eclipse’s EZ030 is the unfilled grade of our modified PTFE. It maintains all the benefits of standard PTFE in terms of chemical compatibility, friction characteristics, and temperature range.

Its advantage over standard PTFE lies in the fact that the modified version allows better material adhesion during processing, resulting in a denser finished structure. The denser structure allows for better-machined finishes on seals as well as greater permeation resistance.

This results in a seal that’s unmatched for services in gaseous media like oxygen, hydrogen, nitrogen, and natural gas. Common applications for EZ030 are couplers, ball valves, and seats.

Elevate Your Next Project with Eclipse

Whether you’re troubleshooting a sealing application or looking for the best material for the job, Eclipse has your back.

Fill out a project request form to get started >

Should You Use a Cantilever V-Spring? Here Are the Pros and Cons

Tue, 19 Apr 2022 03:17:00 GMT

Shortly after the discovery and use of PTFE as a seal material, the need for a secondary energizing method became apparent.

Unlike rubber or urethane which possess elastic and spring-like properties, PTFE will not return to its original state once deformed.

This is obviously not a desirable trait for sealing material, especially in dynamic sealing applications. PTFE seal designs were soon developed to incorporate energizing elements such as O-Rings and metallic springs. These energizers ensure the PTFE seal is always in contact with the sealing surface.

Eclipse utilizes three different spring types to internally energize PTFE and other polymer seals, each with its own advantages and drawbacks. Below we’ll discuss in detail some of the pros and cons of Cantilever V-Spring and some of the applications it’s best suited for.

The Advantages of V-Spring

V-Spring consists of thin strips of sheet metal, most often 301 stainless steel, that is formed into a V shape. Relief cuts are put into alternating sides of the V to allow the spring to be formed into a circle. The shape acts as a sort of cantilever leaf spring inside of the seal jacket, hence the name Cantilever V-Spring.

Energy and load are focused at the ends of the V-spring. This coincides with the seal jacket geometry to create a concentrated point-load at the leading edge of the seal. This configuration is ideal for reciprocating applications that need to not only seal but scrape away or exclude media.

They’re Effective With Many Media

V-Spring combined with a highly wear-resistant seal material like UHMW-PE can create an extremely effective sealing solution for thick and viscous media like adhesives and epoxy resins.

To further amplify the scraping and sealing potential, V-Springs can be stacked or nested within the seal jacket. This will multiply the spring load and allow the use of multiple, redundant sealing contact points on the jacket.

They Have a Wide Deflection Range

V-Spring has the widest deflection range out of all the available spring types. It is well suited for very large diameter components where hardware misalignment, dimensional tolerances, and clearances are substantial. The increased deflection range ensures the seal is always in contact, even in fluctuating gland conditions.

They Can Withstand High Temperatures

The shape of the V-Spring also makes it well suited for very high-temperature applications. A PTFE seal jacket at 450°F or higher can soften enough that a spring-like Canted Coil can actually start embedding into the seal lips.

V-Spring’s comparatively large, flat footprint resists embedding in the jacket much better. Therefore, V-Spring is the spring of choice for high-temperature requirements.

They Can Be Filled With Silicone

Another unique attribute of V-Spring is its ability to be Silicone-filled. This is often employed in FDA and food processing applications that use Clean-In-Place procedures.

The Silicone fills the entire spring cavity encapsulating the spring but still allows it to provide energy to the seal jacket. This keeps media from packing into the spring cavity and around the spring, which can be very hard to clean out.

They’re Cost-Effective

While V-Spring has many performance advantages in the right application, many times it is chosen based on cost alone, especially when high volumes are needed.

V-Spring is manufactured by forming strips of sheet metal through progressive dies and punches. It’s the most economical spring to produce in quantity and is often sold in spools hundreds of feet long.

It’s also the most economical spring to cut to the right length for the seal diameter and weld in a circle. V-Spring can be welded, like most sheet metal, with a simple resistance welder.

They’re Fast to Make

Run rates are optimized with this much faster technique, especially compared to Canted Coil springs which are our Eclipse laser welds. While it’s possible to install V-Spring into the jacket without welding, Eclipse fully welds every spring it produces to make certain that the load is consistent around all points of the seals.

In volumes of tens of thousands of pieces, where some tooling costs can be amortized and diameters are relatively small, a circular spring pattern can be etched into sheet metal and then formed into the V.

This eliminates the cutting and welding steps altogether providing the lowest cost spring energized seal possible.

The Disadvantages of V-Spring

While the focused, point-loading of V-Spring was listed as an advantage earlier, this very same aspect can be a drawback in some applications.

V-Spring is rarely used in rotary applications where the relatively high point-loading would needlessly accelerate the wear of both the seal and the hardware.

They Gradually Decrease Spring Load

V-Spring possesses a very linear load curve, meaning load increases proportionally with the amount of compression of the spring. This means that as the seal wears, the spring load gradually decreases. Therefore, the seal might be overloaded initially and underloaded near the end of its wear life.

This is in contrast to the Canted Coil spring which has a very flat load curve. Spring force stays almost constant over its deflection range. This makes it a much better choice for high-speed and torque-sensitive rotary applications as the load will vary a little over the life of the seal.

Wear life can also be optimized with the predictable, controllable, and constant spring force.

They Can Yield

Another disadvantage to V-Spring is its potential to be yielded. If the spring is over-compressed or distorted in some way, it will no longer function.

This can be a problem if a sealing system has a possible high back-pressure scenario. Eclipse has seen V-Spring over-compressed and fully flatten in a down-hole drilling application that saw an unexpected back-pressure event.

Canted Coil, on the other hand, can be fully compressed without damage and is much more difficult to yield in any direction. This makes it the better choice for seals that need to be installed in hard-to-reach glands where the seal needs to be contorted and/or maneuvered in multiple ways.

They Have Diameter Limitations

V-Spring also has some lower diameter limitations unlike Canted Coil or Helical spring.

At smaller diameters, the inner “tabs” of the V-Spring will start to overlap and will crowd around the inside diameter. This limits the small diameter potential of some series of V-Spring.

Eclipse is Here to Help

V-spring is widely used throughout the sealing industry and has many advantages.

It might be the best choice for your sealing application or there might be a better option.

Either way, Eclipse is here to utilize its years of experience and engineering expertise to specify the right spring energized seal to meet your sealing goals.

Fill out a project request form now >

How (And Why) to Choose the Right Seal for Electric Motors

Fri, 25 Feb 2022 04:48:00 GMT

The current global electric motor market is valued at more than 100 billion dollars and is slated for continued growth in the decades to come.

It’s estimated that more than 30 million electric motors are produced every year. The increased development of robotics and automation in many industrial processes as well as demand for numerous consumer applications continues to fuel growth.

The recent push and increased adoption of electric vehicles, including everything from electric bicycles to automobiles is a prime example of the expanding need for electric motors. As we’ll see, the sealing requirements can be very different for an electric motor compared to a seal in a traditional internal combustion engine.

New technologies and applications also find electric motors serving new purposes and creating new requirements. Eclipse is at the forefront of meeting the unique sealing needs of the electric motor industry.

High Speed, Dry Running

Electric motors have many advantages over an internal combustion engine. We won’t discuss the extent of them here, but an electric motor’s few moving parts and limited friction points mean there’s no need for internal lubrication. This is in obvious contrast to an internal combustion engine which is filled with pressurized, circulating oil.

The dynamic shaft seals in a traditional gas or diesel engine are aptly named “oil seals” as they both keep oil or grease inside and the external environment out.

An oil seal usually consists of a stamped metal case over-molded with an elastomeric or rubber material to create a sealing lip. The metal case facilitates a press-fit in the hardware, while the lip rides on the shaft creating a seal.

Oil seals utilize the system oil to both lubricate the backside of the lip and to help keep localized heating in check. Without this lubrication, a traditional elastomeric oil seal will quickly overheat and fail.

Unfortunately, dry running capability is exactly what an electric motor typically needs. Any electric motor operating in an outside or unclean environment likely needs a primary shaft seal to keep dust/debris/water or possibly lubricants from other systems components from getting into the internals of the motor. Containing often highly charged electrical components, contaminants or fluids can quickly foul the motor operation.

To compound the difficulty of seal dry running, electric motor speeds are often much higher than internal combustion engines. Current production motors in electric vehicles can spin as fast as 18,000 rpm.

This is about 3 times higher than the maximum speed of most automobile gas engines. Smaller motors in other applications can run at even higher speeds.

As enhanced electric motor design continues to develop, along with the utilization of advanced materials, higher and higher motor speeds are expected. This is done in the pursuit of further efficiency as a motor with higher speed capability can better exploit advantages in mechanical gearing.

The seals in the motor will need to survive high-speed running and provide extended service life demanded by consumer products all without lubrication.

Low Friction

One of the other often stringent requirements for electric motor seals is extremely low running friction. The drag created from seals is never a desirable attribute, but the electric motor applications heighten the need for as little frictional loss as possible.

In battery-powered applications, such as electric cars, any friction created by the seals translates into efficiency losses in the power output of the motor. If the motor is working harder due to this, more energy is expended to move the vehicle forward and more of the battery is being used.

One of the chief concerns with electric cars is the available range per charge of the battery. It’s a major selling point to extend the range as much as possible, and manufacturers are looking to reduce inefficiency losses in every possible way. The motor seals will be a contributing factor in these losses, so the lower the friction, the better.

Another industry that frequently requires low friction motor seals is precision robotics and automation. Motor size can be limited due to space constraints.

For example, a motor that needs to be housed within an articulating robotic arm will have constraints for both physical size and weight. Low friction seals help make sure motor power is maximized so the smallest and lightest motors can be utilized.

Another important characteristic related to low friction seals is the smoothness and consistency of the dynamic motion. A robot responsible for placing electrical components on a circuit board requires high precision and very fast starting and stopping motions.

Rubber or elastomeric seals can exhibit what’s often called “ stick-slip ,” which is a function of the static friction being much higher than the dynamic friction. The resulting jerkiness is not desirable in these types of applications.

Eclipse Has the Solution

If you need a long-lasting seal, capable of high-speed, smooth dry running operation with very little friction — a PTFE seal is what you need.

While this can take many forms, electric motors most often utilize Cased PTFE Lip Seals. The metal case, usually stainless steel or aluminum facilitates an OD press-fit into an open gland much like an oil seal.

Eclipse can design a PTFE cased lip seal to retrofit most oil seal glands.

The Best Materials and Applications for Wear Rings and Bearings

Fri, 28 Jan 2022 13:09:00 GMT

All moving shafts, whether they’re reciprocating or rotary, require some form of guidance to avoid metal-to-metal contact. Relative motion during use will always wear down your appliance.

There are many different styles of bearings available in the marketplace today. In some cases, a rotary ball and race are used especially in rotary service due to side loading of the driven shaft.

While linear ball bearings like ball screws are used in CNC lathe equipment, there are 2 common and inexpensive methods for guidance for reciprocating and/or oscillating as well as slow rotary. These are to use either a bronze bushing to allow a shaft to rest on and carry sideload or a polymer bearing.

Common Applications for Polymer Bushings

Eclipse Engineering designs a variety of polymer bushings for reciprocating, oscillating, and slow rotary service.

Some very common applications where you’ll find this style of bushing are cylinders — both pneumatic and hydraulic. These bushings have the capability to handle extreme side loads while keeping the shafts centered in their respective bores. This allows seals to maintain fluid within the working cavity.

The Features of Bronze-Filled PTFE Bushing Materials

Some of the more common bushing materials are filled PTFE or Teflon ® . Eclipse’s ET010: Bronze-filled PTFE is frequently used for bearings and wear rings across all industries.

The filler is dependent on shaft material, media, and speed. In severe conditions, polyester-filled resins are often used with different forms of polyester cloth or Kevlar to improve the load-carrying capability.

Eclipse’s EC131 material is an excellent example of this.

Keeping the Shaft Centered

Keeping the shaft centered with little or no eccentricity is paramount to allow the seal the best opportunity to retain fluid in the system.

Many of these bushings or wear rings are self-lubricating, but in cases where a non-lubricating polymer is used, the design may incorporate a groove in the bushing to retain some type of added lubrication to the system.

How to Calculate the Load Bearing Ability of Bushings

As in all engineered bushings, there are some basic assumptions necessary to calculate the load-bearing ability of the bushing. But first, we’ll provide a little background about the material used.

With seals, we often consider the filler material to aid in reducing the wear of the bushing.

Calculation of the load-carrying ability of the polymer is generally calculated by looking at the yield of the material under a compressive load and then applying some Factor of Safety to this number.

One of the advantages of using polymers for bushing type materials is that they don’t point load like a bronze bushing, so much of the load is distributed over a broad area as compared to metallic bushings.

A good “rule of thumb” is to consider the supported area to be about 40% of the total area when designing a bushing for your application. We can do this because polymer bushings will deform as the load is increased allowing more area to carry the load.

Materials such as filled Teflon® have a compressive strength of 1000 PSI, where a polyester resin-based bushing with filler can have as high as 50,000 PSI.

Other Bushing Materials

There are many other materials that can be used as bushings, such as glass-filled Nylon, or Teflon-filled Acetal. Each provides different characteristics for carrying load.

Cost always enters into the discussion with glass-filled Nylon, which may be injected molded, and is often a low-cost solution for higher volume applications with load-carrying capability of about 36,000 pounds compressive.

Best Applications for Certain Bushing Materials

While Nylon has tremendous load-carrying capability, under heavy loads it can be very noisy. Nylon can even cause hydraulic cylinders to jump due to the friction between the interface of the bushing and the shaft.

We often have to review the applications to determine the suitability of some materials.

Some examples of when these considerations come into play are pumping oxygen where certain fillers or some lubricants are not compatible. FDA compliance may also be a factor.

Another good example is trunnion pins for bridges. Sitting in seawater, they need to carry very heavy loads while surviving in their environment.

Hydraulic cylinders appear to be a very easy application with plenty of surface area to work with. But unknown factors such as side load, or the need for the bushing to provide extremely smooth operation under heavy load will drive the material and shape of the bushing being applied.

Slow-turning rotary unions generally don’t need a great deal of support, with little or no side loading. But due to the number of seals that may be present in some rotary unions, keeping the joint centered is critical to keeping seals performing and providing long life for the smooth operation of the union.

There are many industrial bearings that are injection-molded to size, but oftentimes these bearings are machined from tubes cut from standard cross-section strips of material.

Bearings to Fit Any Application

Eclipse Engineering designs and manufactures bearings to fit your specific application.

We have a history of designing in many industries, from under the water to other planets. This experience gives us a solid understanding of the loads that you may encounter in your specific application.

We also manufacture bushings in-house from under .100 inch up to 50+ inches with varying cross-sections to meet your application needs.

Call us today to get a quote for your bearing needs >

The Pros and Cons of Using UHMW for Your Sealing Application

Mon, 27 Dec 2021 10:01:00 GMT

Aside from PTFE and PTFE blends, one of the most used seal materials at Eclipse is UHMW, or Ultra High Molecular Weight Polyethylene.

Polyethylene is the most common and prolific plastic in the world today, utilized in everything from consumer-grade packaging to bags, bottles, and medical implants. It’s available in varying densities, such as Low Density (LDPE), High Density (HDPE), and the aforementioned UHMW.

The seal world focuses mainly on UHMW employing the favorable properties of the added density. Below we’ll discuss the benefits and advantages of using UHMW as a seal material, as well as some of the drawbacks.

The Advantages of UHMW

UHMW has many desirable properties for a seal material. Probably its most notable attribute is its wear, abrasion, tear and cut resistance. If you have a thick, heavy plastic cutting board at home, it’s likely made out of UHMW.

So, you may have firsthand experience with UHMW’s toughness. Any material that you can cleave with a knife resulting in minimal damage will also serve well as a robust seal material.

Compared to even some heavily filled PTFE blends , UHMW’s wear resistance can be more than 10 times better. A seal working in abrasive media can greatly benefit from the properties of UHMW.

For example, Eclipse has had immense success employing UHMW spring energized seals in paint processing and dispensing equipment.

While paint might not be initially thought of as an abrasive media, it often contains very hard ceramic and metal oxide particles which can act like sandpaper against a seal. Eclipse’s EU038: Ceramic-filled UHMW is tailormade for such applications providing the maximum amount of wear life possible.

UHMW’s toughness also comes into play in heavy excluding and wiping applications. Media such as resins and epoxy require seals with a heavily point-loaded, leading-edge for scraping. Any wear or loss of this edge gives an opportunity for media to be forced under the sealing lip in a reciprocating application. UHMW’s durability helps maintain the sharp scraping edge for extended service intervals far better than any other seal material.

UHMW’s coefficient of friction is also quite low. While not better than PTFE’s famously low friction, it’s far better than any elastomer or urethane seal material and lower than most comparable plastics such as Nylon or Acetal. This is important when it’s used as a guide or wear ring or in a sealing application where the stick-slip nature of an elastomer is undesirable. In most cases, it can be used unlubricated.

Chemical compatibility or resistance to chemical attack is also an important attribute for a sealing material. While again, not being quite as resistant as PTFE, UHMW rates good or excellent with most media including many solvents and acids. It has low moisture absorption and typically outperforms PTFE in terms of leakage control in water sealing applications. Virgin UHMW also has the benefit of being FDA compliant.

Lastly, UHMW is relatively cheap and readily available. Especially in extruded rod form, UHWM can be less than 10 times the cost of PTFE. In high-volume applications where the raw material price is a significant portion of the final piece price, UHMW can be very economical.

The Disadvantages of UHMW

We have a material that’s very tough and abrasion-resistant, low in friction, chemically compatible, and relatively inexpensive. So far there’s a lot to like about UHMW as a seal material.

Unfortunately, there’s one weakness that rules out UHMW for many applications in the seal world – its temperature range.

While UHMW’s lower temperature limit is quite good (it can be used in cryogenics) it’s the upper limit that often severely limits its potential. UHMW can start seeing reduced properties at 150°F [65°C] and has a continuous operating limit of 180°F [82°C].

While this means UHMW can’t be used in many applications that operate above this temperature, it also largely limits its use in rotary applications. With any amount of rotary surface speed, the interface temperature due to friction between the seal and the dynamic hardware surface can easily exceed the upper limit of UHMW.

This can even be the case if the ambient environment of the system is cool or at room temperature. Since a rotary seal is continuously operating on the same area of the hardware, there’s little opportunity for heat rejection.

Therefore, UHMW is infrequently used in rotary applications unless the motion is very, very slow. It’s typically best suited for reciprocating applications operating at nominal temperatures.

Along with this, UHMW has a relatively high coefficient of thermal expansion. This means it will dimensionally shrink or grow along with temperature changes. Because of this thermal instability, it might not be the best material for high-precision parts.

The thermal limitations can also make the machining of UHMW challenging. Due to localized heating while cutting, a part may dimensionally change drastically after it has stabilized to room temperature.

UHMW is also notorious for “chip wrap” while machining. This is because the chip, or material being cut away, stays in a long continuous strand rather than breaking off. (But, by all means, leave the machining to us!)

Is a UHMW Right for Your Application?

Have a reciprocating application sealing viscous or abrasive media, that’s operating at ambient temperatures? If you’re not already using a UHMW seal, there may be an opportunity for significant improvement in both wear life and sealing performance.

While not right for every application, UHMW can work wonders in certain situations.

Eclipse’s decades of experience in both the design and manufacturing of seals can ensure the best possible sealing solution is implemented. Whether it’s UHMW, PTFE, or something beyond, Eclipse has you covered.

Fill out our request form for your custom sealing application >

Spring Energized Seal vs. O-Ring: Which is Better?

Mon, 22 Nov 2021 13:56:00 GMT

Spring Energized Polymer Seals and O-Rings are very different products, yet they can ultimately accomplish the same goal of sealing a system.

The humble O-Ring is, in simplest terms, a ring of rubber. A Spring Energized Seal consists of an engineered plastic jacket, usually a PTFE blend or UHMW-PE, and a metallic spring element. One is made in quantities of tens of thousands and then stocked on a shelf, one is machined and assembled per individual order.

While both are seals, their commonality in design, intent, and functionality is limited. The applications where each is successfully employed can be very different.

But is a Spring Energized Seal always better than an O-Ring? Below we’ll discuss some of the strengths and weaknesses of each of these seals and why some applications might benefit more from one than the other.

O-Rings

One of the chief advantages of the O-Ring is also one of the most obvious: cost and availability. It’s hard to argue with a seal that can cost only a few cents.

There are many applications, particularly in high-volume consumer products, that would likely benefit greatly from the advantages of a Spring Energized Seal. But a seal that costs dollars instead of cents can’t be financially viable in some products. Despite potentially being inferior in sealing performance and wear life, an O-Ring might be the best option simply due to price.

Being affordable isn’t the only advantage of the O-Ring. If operating within the recommended parameters of the material, an O-Ring will typically provide far better sealability than a PTFE Spring Energized Seal. Being a soft elastomeric material allows it to conform to hardware surface irregularities with ease.

In many cases, an O-Ring can approach “zero-leak” sealing performance. Most of the time this can be accomplished on poor or “as machined” hardware surface finishes. This can’t always be said for Spring Energized Seals, which even under the best of circumstances can allow small amounts of leakage with some media.

Another key advantage of O-Rings is the ease of installation and handling . Installation is often as simple as stretching the O-Ring into a groove. The procedure is intuitive, uncomplicated, and difficult to get wrong.

Spring Energized Seals, on the other hand, can be easily damaged with improper handling. Scratches or gouges to the sealing surfaces might not be immediately apparent but ultimately result in leakage.

Spring Energized Seals are also directional, meaning they must be installed facing the right direction to operate correctly. Some amount of product knowledge and proper handling techniques will be necessary for correct installation.

The disadvantages of O-Rings will become apparent when we talk about the benefits of Spring Energized Seals.

Spring Energized Seals

Because of the attractive price point and ease of availability, many applications start life with O-Rings in place. If the sealing system is functioning satisfactorily with O-Rings, there’s little reason to change. But in many cases, the humble O-Ring falls short of the desired goals.

While O-Rings frequently work great in static sealing applications, as soon as dynamic sealing is required, immediate weaknesses can be seen. A Spring Energized PTFE or UHMW-PE seal can provide long-lasting sealing performance in applications where an O-Ring would be shredded in minutes.

The higher the speed of the motion, whether reciprocating or rotary, the more likely a Spring Energized Seal will be needed. PTFE’s ability to run without lubrication also presents a distinct advantage.

The coefficient of friction of PTFE can be more than 10 times lower than that of most elastomeric O-Ring materials. Applications that are friction and torque-sensitive, such as precision robotics , will benefit greatly from a PTFE Spring Energized Seal. Problems such as “stick-slip” are mitigated when using PTFE versus an O-Ring.

The engineered spring energizers also contribute to favorable friction characteristics. Canted Coil Spring is specifically designed to provide constant load over a varying deflection range making it ideal for rotary and precision applications.

Conversely, some applications will require very high spring loading to perform as intended. Cantilever V-Spring can provide a high point load on a specific point of the seal. This combined with a UHMW-PE jacket will supply excellent media scraping and wear life in reciprocating applications.

Machinery such as epoxy or adhesive dispensing equipment demand Spring Energized Seals. These conditions are far outside the capability of any O-Ring.

Spring Energized Seals’ ability to handle temperature ranges from deep cryogenics to over 500°F, also marks a distinct advantage over most O-Rings. Some applications might function fine with O-Rings at ambient temperatures, but when testing at the extremes, leakage occurs.

Some aerospace requirements mandate sealing performance at -70°F. This is just beyond what most elastomers are rated for. A Spring Energized Seal has this covered with ease.

It’s usually standard procedure to check through chemical compatibility charts when selecting an O-Ring. Some caustic chemicals and compounds are simply not compatible with the common O-Ring materials. A Spring Energized Seal with a PTFE jacket is virtually impervious to all but a few specific substances on Earth.

Shelf life and cure date are also important considerations when using O-Rings. PTFE Spring Energized Seals have an indefinite shelf life and are impermeable to UV and aging degradation.

Applications that require long service life can benefit from these aspects. An O-Ring might function perfectly in a waterway gate for a large dam. But a service interval requirement of 50+ years will make a Spring Energized Seal the best choice.

Have Questions? Eclipse is Here to Help

While it’s easy to see there are many advantages to Spring Energized Seals, they may not be right for every application.

When you aren’t sure which seal you need, just ask us!

Eclipse is here to employ our decades of experience to provide the best sealing solution to your specific application. Whether it be a simple O-Ring or a multi-spring PTFE seal, Eclipse is here to help.

The Ultimate Guide to Seal Glands for Any Project

Thu, 21 Oct 2021 07:05:00 GMT

While seal performance, leakage control, and wear-life characteristics are frequently discussed, one critical aspect of a successful sealing system is often overlooked — how a seal is contained in the hardware.

Whether you want to call it a gland or a groove, the physical space for housing a seal is an important part of the system’s performance. The type of gland greatly dictates the ease and even the possibility of seal installation. Certain seals demand specific gland types, so it’s essential to take these requirements into account.

Below we’ll discuss the most common types of rod and piston glands and what seals work best for each one.

Solid Glands

The solid gland is the simplest way to contain a seal. It consists of nothing more than a rectangular groove cut in a housing or piston. Solid glands are prevalent throughout the industry because they’re mostly commonly used to contain O-Rings .

Solid glands work fantastic for O-Rings because they count on the elasticity of the O-Ring for installation. Stretching an O-Ring into a groove on a piston is usually a simple process.

Switch to a much harder and much less elastic material such as PTFE and the task can become quite difficult. PTFE seals such as Eclipse’s ESR Seal Rings and EDS Channel Seals are designed to work in solid glands in conjunction with an O-Ring. This doesn’t mean however, that installation will be trivial.

In the case of piston configurations, the PTFE seal will need to be stretched to be installed into the groove. This can become quite difficult with larger cross-section seals. Special installation tools may be required to evenly stretch and push the seal without damaging it.

Once in the groove, the seal will likely need to be resized to be properly seated. This is due to the inelastic nature of PTFE. Higher modulus materials such as UHMW can be even more challenging.

In rod seal configurations, a PTFE seal will need to be folded in on itself to make it small enough to be placed in the groove. In a process often called “kidney beaning,” the seal is folded as gently as possible to avoid any hard creases which can permanently damage the seal.

Ease of seal installation into a solid gland can be very dependent on the diameter of the seal. At very small diameters it may not even be possible. You should also consider the difficulty of removing seals from solid glands. This often can’t be done without damaging the seal.

Spring Energized Seals are generally never recommended to be used in solid glands. The geometry of the seal jacket contributes to the rigid nature of the PTFE and the risk of yielding or damaging the spring is very high.

Though in some special cases it is possible (like a small cross-section spring going into a large diameter rod gland) but compromises in seal performance and longevity are needed to facilitate this.

Open Glands

Open glands are essentially a counter-bore in the face of a hardware surface. Since one side of the gland is open, they’re typically reserved for seals with metal cases. The case OD is designed to be slightly over-sized compared to the groove diameter facilitating a light press fit.

The press fit on the case holds the seal in place. Seals without a case have the potential and tendency to “walk-out” of open glands, even in pure rotary applications. Therefore, products like Rotary Lip Seals , Cased Spring Energized Seals , and MicroLips are best suited for open glands.

Split Glands

Split or 2-piece glands consist of an open gland with some means of mechanically closing off the open side once the seal is installed. This is commonly accomplished by a simple cover-plate affixed by a bolt pattern.

Split glands offer many advantages. Seal installation becomes as simple as possible with many cases being a “drop in” procedure. Without having to manipulate or contort the seal or use any specialized installation tooling, risk of damaging a seal during installation is largely mitigated.

Removing and replacing a worn-out seal also becomes a straight-forward affair. Seals in high-wear applications that need to be replaced regularly or seals that need to be serviced in the field will greatly benefit from the uncomplicated split gland.

With spring energized seals in critical gas sealing applications and cryogenics, hardware surface finishes typically need to be highly polished for the best control leakage. The split gland makes the polishing procedure in the groove easier since the gland is open.

The main drawback to the split gland is that it requires extra hardware components and fasteners. Not all hardware configurations present uncomplicated ways to split the gland. This is especially true when redundant seals are needed. Solutions such as a seal carrier group can potentially help. Glands can also be closed by using snap-rings in certain situations.

Despite possibly adding complexity to the hardware, some sealing solutions will have no other option but to require a split gland. Very small O-Ring energized seal rings and many spring energized seals cannot be installed in any other gland type without damaging the seal.

Stepped Glands

In certain situations, spring energized seals can utilize what’s known as a stepped gland. This is basically an open gland that has a small step or barb that retains the seal on the open side. The seal will need to be installed heel first and the lip will need to be the scraper style to lock in behind the step.

The height of the step will vary depending on seal cross-section and spring size, but it’s usually 0.020” or less. This is all that’s needed to retain the seal, even in demanding fast reciprocating applications. In fact, once installed the seal will be very difficult to remove without damage.

Stepped glands allow for easy seal installation but don’t add any extra hardware components like a split gland. This is the chief advantage of the stepped gland. It’s often employed in piston seal applications where keeping the piston a “1-piece” design is highly desirable.

The stepped gland is relatively difficult to machine in the hardware compared to the other gland types. Small details like chamfers and tool radii need to be carefully controlled to achieve the proper gland dimensions and functionality.

Eclipse is Here to Help

How a seal actually gets put in the hardware is a critical aspect that sometimes gets overlooked. Seal gland requirements can have a large impact on the hardware assembly procedure and overall design.

At Eclipse we have much more than your standard catalog recommendations to offer.

Some of Eclipse’s greatest engineering challenges have centered around seal installation and gland requirements. Eclipse is here to utilize our decades of seal design and manufacturing experience to help specify the best seal and gland configuration for your application.

The Best Spring Energized Seal Lip Styles For Every Project

Fri, 17 Sep 2021 17:54:00 GMT

Spring Energized Seals can be found in all kinds of applications across the spectrum of industries and sectors. While the pros and cons of the different spring types contained in the seal are often discussed, the style of sealing lips can also have a significant impact on performance.

Every spring type has at least 4 standard lip style options, so choosing the right style for your application is critical. There are a number of design factors that need to be taken into account to ensure the best option is chosen for the application.

Hardware configuration, seal installation direction, media type, and dynamic motion all need to be taken into consideration to correctly specify a lip type.

Eclipse’s team of experienced engineers is here to recommend the best design, whether standard or custom. Below we’ll discuss the basics of the common lip styles and where they’re used.

Standard Chamfered Lip Design

In Eclipse’s spring energized seal catalogs , the standard lip design is referred to as the LW style. It consists of chamfered lips on both the OD and ID of the seal. This lip style is suited for most general-purpose applications.

The chamfers make for easy seal installation and reduce the risk of damage in gland configurations where the seal must be installed face (spring side) first.

This can also be particularly important in blind installation situations. For example, when a rod seal is positioned in a groove that is located deep inside an assembly, there will be no way to externally guide the shaft installation through the seal.

But more than just lead-in chamfers for installation, the sealing point is carefully positioned to allow broad energizing from the spring. This extends wear life and helps promote consistent sealing performance throughout its service life.

Scraper Lips

The scraper lip design puts a sharp point on the leading edge of the sealing lip. It can be on either the ID or OD lip of the seal, or both lips depending on whether it’s a rod or piston seal application and the gland configuration.

The scraper lip puts a focused point contact between the seal and media allowing for wiping or excluding action. Scraper lips are often found where a seal is being used as an environmental barrier keeping outside debris or contamination from entering a system.

Scraper lips are also often employed in reciprocating applications sealing viscous media. A chamfered lip can potentially allow media to build up underneath the lip and cause a hydroplaning effect, allowing leakage. The scraper lip helps prevent this.

With a canted coil spring, the scraper lip can be “cut back” on the dynamic side of the seal. This shortens the lever arm of the lip and further concentrates the spring force. These designs are used when maximum scraping action is required.

The scraper lip is also used for seal retention in stepped glands. The sharp point locks in behind the barb of the stepped gland ensuring the seal is securely held in place. Often a step height of 0.020” or less is all that’s needed to properly retain the seal.

Radiused Lips

Sometimes called bubble or beaded lips, lips with a full radius are well suited for specific applications. The radius allows for a large contact area with the mating hardware. This extended surface contact creates a longer path for any leakage to penetrate thus providing excellent seal-ability in gas media.

The geometry also allows Eclipse to use special tooling and machining techniques when turning the seal jacket to provide a super finish on the surface.

When applied to Eclipse’s EZ030: Virgin Modified PTFE , the resulting finish can provide enhanced gas sealing performance and is often employed in cryogenics and other critical sealing applications.

Radiused lips can also be beneficial if the seal needs to pass over any ports or other irregularities in the hardware. The lack of any sharp edges and gradual radii will permit smooth transitions over hardware features. This minimizes the possibility of unnecessary seal damage.

Get a Custom Lip Configuration at Eclipse

Eclipse is by no means limited to the standard lip styles listed in our Spring Energized Seal catalogs . Our team of engineers is here to specially tailor the best sealing solution possible for your specific application.

While the lip styles we discussed serve well in many sealing systems, simple lip geometry changes can potentially yield large performance gains in areas such as leakage control and wear life.

Using a radiused lip in a scraping application will probably not work out well. Using a standard chamfered lip design to seal Hydrogen will likely be less than optimal.

If you’re utilizing a standard lip configuration and it’s leaving much to be desired, Eclipse is here to help.

Contact Eclipse today if you have a new project or are looking to optimize a current setup >

How to Control Loads to Allow Fine Adjustments with Seals

Wed, 11 Aug 2021 21:14:00 GMT

Controlling friction using the properties of Teflon® and adjusting the durometer of an energizing elastomer allows us to adjust the load and control the force the seal applies.

Seals are often used as a barrier or exclusion device. When considering a device that becomes sterilized, seals often protect the internal components of that device.

Some systems require adjustment of the mechanism. Friction becomes a factor when making internal adjustments. An O-ring is always the easiest solution for sealing. But for fine adjustments, reducing the friction allows more control of the device.

The coefficient of friction of a rubber O-Ring is about 1. Teflon is as low as .04. But, the force to move is also dependent on the load from the O-Ring energizer under the Teflon seal.

This force pushing up can be adjusted in 2 methods.

One is simply to reduce the squeeze the O-ring is presenting behind the seal. The second is by adjusting the durometer of the rubber element under the seal.

Reduce the Squeeze of the O-Ring

Squeeze may or may not be an easy fix depending on a couple of factors. One is adjusting the thickness of the cap over the O-ring. When dealing with straight Channel or Cap Seals the web thickness is often so thin that adjusting the thickness might not be practical.

Making a cap seal thinner takes life away, and at the same time makes it too fragile to easily install a gland . With thicker caps, the cross-section can be reduced, thus reducing the amount of squeeze on the Cap from the underlying O-Ring.

The gland can be made deeper to reduce squeeze. While this results in a lower squeeze, hardware can stop making the groove deeper.

Ensuring there’s enough width in the groove ensures the gland isn’t over-occupied, which often results in a higher squeeze.

Lower the Durometer

As a last line of defense, lowering the durometer even by 10 points can result in a 50% reduction of force from the elastomer. This is generally easy to accomplish in common compounds, but availability may become limited depending on the compound of rubber.

One other option is to switch from a standard SAE O-Ring to a metric O-ring cross-section. SAE and Metric O-ring cross-sections aren’t the same, so we can take advantage of this difference in varying squeeze in the assembly.

The only caveat to this is to ensure occupancy remains at acceptable levels.

All these options are viable depending on the sealing situation, and what level of seal-ability is acceptable.

There’s another level of control using spring energized seals with a variety of springs. By changing geometry we can cause a spring energized seal to have very light loads and seal.

But with all sealing applications, we may give up the amount of pressure the seal will tolerate.

It’s possible to make a lip seal, normally used in rotary service, to seal both reciprocating and rotary action.

I’m saving Spring seals and rotary lip seals for another session with the understanding that these 2 forms of sealing often result in lower loads while providing a high degree of seal-ability and changes in gland structure. This isn’t often available due to gland constraints.

Get Started On Your Next Project

Eclipse Engineering designs and manufactures all of the seals described above and more. If you have a project, we have a seal to bring it to life.

We take your ideas and apply them to your hardware to create a solution that fits your unique application.

Ready to take on a new project that needs a seal?

How to Use Tight-Tolerance PTFE in Your Next Manufacturing Project

Mon, 19 Jul 2021 19:28:00 GMT

Author: Doug Montgomery

The machining of polymers such as PTFE, still remains somewhat of a specialty operation. While there are a plethora of machine shops dotted across the country focused on metal turning and milling operations, few specialize in plastics.

Only someone experienced in metalworking might call machining something like PTFE easy. PTFE is much softer and easier to cut than something like steel or aluminum.

While this certainly is true, polymers present their own unique set of manufacturing challenges, especially when tight-tolerance parts are required. And with Eclipse’s business of aerospace and specialty applications , they almost always are.

Though Eclipse designs and engineers the majority of the parts it manufactures, we still frequently entertain the machining of customer-designed seals and components. But customer prints tend to include dimensional tolerancing not suitable for process capability with PTFE and other polymers.

Calling out a +/-0.001” on a 15” OD isn’t very realistic. We’ll also see why in many cases, tight tolerances are not necessary for seal functionality and are likely driving up costs.

To help you with your next project, here’s our guide to PTFE and the challenges it can present while manufacturing.

The Inherent Instability of PTFE

PTFE has lots of unique and desirable qualities as a seal material. Its extremely low friction, broad chemical compatibility, and large temperature tolerance make it function where many other materials don’t.

One not-so-desirable property of PTFE is its non-uniform coefficient of thermal expansion over different temperature ranges. And more specifically, the unfortunate large transition it sees at common room temperatures.

The linear coefficient of thermal expansion of PTFE between the temperatures of 65° to 77°F can be more than 5 times higher than the coefficient in only slightly higher or lower temperature ranges. Therefore, a tight tolerance part machined in a room at 70°F will likely measure small if later inspected in a room either 60°F or 85°F.

So, a part received just off the delivery truck in the middle of winter will probably not measure in spec until brought up to room temperature. Eclipse assumes that part inspection will be done at approximately 70°F.

While this jump in thermal expansion might be an inconvenience for part inspection, it can create a significant challenge in the actual machining of the part. Localized heating from the cutting of the material can transition the part into different thermal expansion zones.

This is especially true in very large diameter PTFE parts where it’s not practical to use coolant while turning. A part measured right off the machine will be significantly different than when it’s measured a few minutes later. Eclipse’s experienced machinists are keen on this challenge and know the needed adjustments to produce the correct part.

Measuring Non-Rigid Parts

One of the most difficult aspects of machining PTFE parts is the inspection of the parts themselves. Most PTFE seals feature a thin aspect ratio that means the diameter is non-rigid and very flexible.

This presents a challenge when using common measurement tools such as calipers and micrometers. Not only will the part simply flex with any contact pressure, but any out-of-round aspects of the part will be very difficult to account for.

Eclipse uses a Visual Measurement Machine (VMM) to precisely measure diameters. The VMM works much like an optical comparator but can take hundreds of measurements to determine diameter. This provides very accurate measurement and takes into account any out-of-roundness.

While the VMM is a great tool for precise measurements, it’s limited to parts 12 inches in diameter or less. Larger parts become increasing more difficult to measure as the diameter increases.

Eclipse has turned to go/no-go gauges to aid in the measurement of tight-tolerance, thin PTFE parts that are large in diameter. This is the best way to ensure roundness is fully considered while measuring.

Tolerance is What Matters

The diameter of parts is usually the most challenging dimension to hold and inspect, especially for large components. But in most cases, the diameter of PTFE seals is not the most critical dimension for functionality.

Take a standard piston seal ring . The functionality of a seal ring comes from the radial cross-section of the seal compressing the O-Ring beneath it. The squeeze on the O-Ring provides energy to the PTFE ensuring constant contact force with the bore and thus providing a positive seal.

Therefore, the cross-section of the seal is really the most important dimension to hold tightly. Similarly, the cross-section, or lip-to-lip dimension, of a spring energized is what determines the spring compression and general functionality of the seal.

So again, this dimension is predominately the most critical aspect of tolerance.

Fortunately, the cross-section is also the easiest dimension to machine precisely, inspect with common instruments, and is proportionally less affected by any thermal instability. Because of this, Eclipse usually focuses its attention on this dimension rather than diameter.

In the case of products such as standard seal rings , many times these are installed in solid glands. This means the seal must be physically stretched to be installed. It’s not productive to tolerance the diameters needlessly tight if the part is only going to be deformed and resized later.

Tight tolerances, particularly on diameters, can also unnecessarily drive up costs by slowing machine run rates. Yes, the VMM can provide very accurate measurements but it’s also not an “in-process” inspection method. The machinist must stop the lathe and go to the inspection room to get a measurement.

Get the Best Quality Engineering With Eclipse

Difficult or time-consuming inspections might be one thing, but Eclipse also knows some tolerance requirements will not be possible to meet.

Through years of experience, we know what tolerance ranges will ultimately be processing capable with a material like PTFE.

Our knowledge is all the more valuable when in-depth capability studies, such as a Level III PPAP are required.

We’re here to work with you to ensure your parts are not only in tolerance but are highly functional and cost-effective sealing solutions.

How Spring Energized Seals Are Made (And Why You Need One)

Mon, 10 May 2021 20:56:00 GMT

Eclipse Engineering designs and builds many types of seals for all kinds of applications. Whether it be a simple O-Ring energized seal ring or multi-lip cased rotary seal, Eclipse covers the spectrum in polymer-based seals for all projects.

With all the seal varieties available in the market today, spring energized seals represent a significant portion of Eclipse’s sales. With our ability to both design and manufacture spring seals in-house, including the cutting and welding of the springs themselves, we can genuinely say spring energized seals are one of our specialties and core products.

Here we’ll discuss the basic functionality and design principles of spring energized seals and discover why one might be the perfect sealing solution in your application.

How Does A Spring Energized Seal Work?

A basic spring energized seal consists of two components, a polymer-based seal jacket and, of course, the spring. Jackets are typically made from one of Eclipse’s many PTFE material blends, which have plenty of desirable properties in a sealing application. Namely, it’s low friction, high and low-temperature range, and broad chemical and media compatibility.

The seal jacket is typically machined in the shape of a “U” following the same design principle of many standard urethane and elastomeric U-Cup seals. Except in some special cases, the seal is usually installed with the open side of the “U” facing the system pressure.

This is done so that the pressure actually energizes the seal to improve sealability. The force from the pressure will expand the seal lips driving them into the hardware sealing surfaces. The higher the pressure is, the more force is applied and therefore the greater the sealing potential.

So why is a spring needed if the geometry of the seal jacket is pressure energized? This is because the spring will be responsible for providing the primary sealing energy at low pressures and start-up conditions. Generally speaking, most spring energized seals are don’t begin to see the benefits from the pressure energy until at least 100 psi.

The necessity of a spring inside the seal jacket is also in large part due to the material nature of PTFE. Unlike elastomeric materials, PTFE possesses very little memory or ability to rebound once deflected. Much like a lump of clay will stay in the position it’s pushed into, PTFE will not bounce back when a force is applied.

So, while a Urethane or FKM U-Cup will function fine without a spring, a PTFE jacket will require a spring energizer to ensure the lips are firmly contacting the hardware in all pressure scenarios.

Different Springs for Different Applications

Eclipse offers three different types of springs that can be used in seals. All have the same functional intent—to energize the seal lips—but one variety might be better suited for an application than another.

Cantilever V-Spring

V-Spring is made by forming and stamping thin strips of metal sheets through progressive dies. V-Spring offers a very linear load curve, meaning that the more it’s deflected, the more force it applies.

It provides more of a point load in the jacket, focusing energy at the leading edge of the seal lips. This makes it desirable in reciprocating applications requiring the scraping of media. Multiple springs can also be stacked together for even greater loading.

Check out our Cantilever specs >

Canted Coil Spring

Canted Coil is one of Eclipse’s specialties and we manufacture our own spring in-house. Canted Coil is typically used in applications where low friction and consistent loading are needed.

It possesses a very unique load curve where spring force changes very little despite varying deflection. This uniform and predictable loading makes it the spring of choice for most rotary applications.

Check out our Canted Coil specs >

Helical Ribbon Spring

A helical spring is made by winding a thin, flat strip of metal into a helix, creating a round tube. Helical has a very steep load curve and offers the highest force per linear inch.

It’s most often used in static face seal applications and in cryogenics where high loading is needed. It can be yielded after being compressed so it’s usually not recommended for dynamic applications.

Check out our Helical specs >

Why Use a Spring Energized Seal?

With many options available for Elastomeric U-Cups and O-Ring Energized Seals available on the market, why would you need a Spring Energized Seal?

A PTFE spring energized seal offers the greatest temperature range possible for a seal. They can be used in cryogenic applications approaching absolute zero all the way to combustion processes at 550°F. No elastomer will function at these temperature extremes.

With a PTFE and stainless-steel spring, chemical compatibility is also maximized. Applications with caustic or aggressive media may not be able to use any type of elastomer.

The shelf-life of a PTFE spring seal is also indefinite. Eclipse has employed spring energized seals in Dam Spillway gates that require 50+ years of service life.

Even in applications with benign media and temperatures, spring seals can still offer an advantage. Yes, you can energize a PTFE jacket with an O-Ring. But the load curve of an O-Ring is very undesirable, especially in rotary applications. A rotary seal using a canted coil will outperform an O-Ring in terms of friction, consistency, and wear-life.

Scraping viscous media such as epoxy resins? Multiple V-Springs inside a filled UHMW-PE jacket can provide optimum sealing and wear-life performance. With redundant sealing points and highly focused load, spring energized seal can do the job no other seal can.

Contact Eclipse today if a Spring Energized Seal might be right for your application >

Eclipse Engineering is Back on Mars with NASA MOXIE Project

Tue, 23 Mar 2021 15:06:00 GMT

In 2004, NASA sent the rovers Spirit and Opportunity to our neighboring planet Mars. It was an exciting day for the world, and also for us at Eclipse Engineering.

We were honored to supply the seals that kept the Martian soil from damaging bearings on the overhead trunnion camera mounts. This was pivotal for keeping the machinery running smoothly.

Our latest venture 17 years later is even more cash today exciting. When Perseverance went to Mars, our seals were installed in a scroll compressor, an efficient rotary oil-less pump.

This scroll compressor is part of the Mars Oxygen ISRU Experiment (MOXIE).

The Mars MOXIE project is now laying the groundwork for man to set foot on the Red Planet.

What is the MOXIE Experiment?

The atmosphere on Mars is 95% Carbon Dioxide (CO2). The MOXIE project is intended to take that Martian atmosphere, pump it through a ceramic treated membrane and produce Oxygen. This process is called Solid Oxide Electrolysis .

The Martian atmosphere is at very low pressure. Because of this, MOXIE uses a scroll compressor which utilizes Eclipse Engineering’s products as the main compressor seal. This takes the Martian “air” and very efficiently raises the pressure. It’s then forced through specially coated ceramic plates heated to 800° degrees Centigrade.

Once that process is done, the output is Oxygen and some Carbon Monoxide and CO2 byproduct.

Why is This Process Important?

It is impossible to carry enough Oxygen onboard a spacecraft to support or survive a manned mission to Mars.

If MOXIE is successful, a future mission — prior to maned travel — would require a small factory to be created on the surface of Mars to produce a supply of oxygen.

This manufactured Oxygen would provide the oxidizer for manned missions to refuel and propel a manned mission back to Earth.

These early steps of the MOXIE project are the groundwork for creating a survivable mission to Mars and the potential to further our exploration of space.

Which Device is Used on the MOXIE Project?

Many mechanical applications require extremely low friction and must work in very caustic chemicals that typically erode most standard seals. Here on Earth, our seals can be found in a variety of applications from controlling aircrafts to sealing chemical pumps.

For this project, a Scroll compressor is used to improve efficiency without the use of oil. Without oil, the compressor is capable of performing over a wide temperature range while maintaining high efficiency.

This is made possible by its design and the use of seals made from a filled PTFE compound (Polytetrafluoroethylene). PTFE or Teflon® has an extremely wide temperature range while maintaining a coefficient of friction around .08.

This low friction allows the pump to operate without lubrication. This becomes especially important in harsh and unpredictable environments.

We are proud to have supplied seals from a variety of polymer materials for over 20 years in many professional industries. Today, we are thrilled to provide devices that can be exposed to extreme conditions such as those found in space, or in other words, a typical day on Mars.

Our devices can be found in practically every industry — under, on, and off this planet — be it undersea propulsion systems, seals for electric motors propelling our newest automobiles, aircraft of all types, and of course, roving around the planet Mars.

How Can Our Seals Help Your Next Project?

You don’t need to be launching into space to get a great device.

Our custom seal and bearing solutions are designed for the perfect fit, no matter the job at hand.

Case Study: How to Form a Combination Seal and Bearing for Limited Space

Wed, 17 Mar 2021 21:47:00 GMT

Every day at Eclipse Engineering we’re faced with sealing challenges coming from numerous application requirements and operating conditions — whether it’s extreme temperatures in an oven or deep cryogenics in a laboratory. From radical rotational speed in a one-time use medical drill to half-a-century service intervals in a dam spillway gate.

Difficult seal applications come from all industries and sectors of the economy.

While far-reaching operating conditions certainly consume their fair share of engineering hours, often one constraint also probes the boundaries of sealing technology and design ingenuity: limited hardware space.

The Client’s Issue

Eclipse was approached by a customer using a pneumatically actuated cylinder to dispense a chemical in a production process. The piston was drawn back in the cylinder thus filling it with the chemical product. The piston was then pushed forward to dispense the chemical out of a nozzle.

Operating Conditions:

Reciprocating Piston Seal
Bore Diameter: Ø1.500”
Stroke Length: 18”
Pressure: 30 psi
Cycle Rate: 2 per minute
Room Temperature
Media: Chemical Agent

The current sealing configuration was a simple O-Ring in a groove on the piston. While this sealing solution proved to work fine in their preliminary prototype testing, the demands of full production exposed weaknesses in the design.

With healthy demand for the end product, duty-cycles and run-rates far exceeded initial expectations. The O-Ring was wearing out quickly requiring costly down-time to disassemble the machine for replacement.

Worse yet, scoring of the cylinder bore was found after extended hours of running. Without any bearings, the piston was making occasional contact with the cylinder wall over the course of the relatively long stroke. Continued damage in this way would result in the cylinder needing to be replaced. This is a much more costly and time-consuming procedure.

At first glance, this might seem like an easy application for an Eclipse Seal Ring and Wear Ring. While this combination is exactly what the application needs, there was one detail that greatly complicated the matter.

The volume of the cylinder had been carefully calculated and specified. This was done to precisely control the amount of chemical that was drawn into the cylinder and thusly dispensed out. Changing the piston dimensions in any way would alter the volume of the cylinder and therefore change the volume of the chemical.

In order to incorporate a Piston Seal Ring and Wear Ring, Eclipse would need more axial room than the current piston allowed. Making changes to the cylinder bore and stroke length to account for decreased volume from a longer piston wasn’t possible.

Eclipse had a scant 0.500” axial length to work with and this was non-negotiable.

The Eclipse Solution

Eclipse knew a Piston Seal Ring would be the proper solution to the seal life problem. Having a PTFE interface on the dynamic surface would provide far better wear life compared to the lone O-Ring. Friction would also be reduced up to one-tenth of the O-Ring, allowing for more even and precise control of the dispensing rate.

But resolving the sealing issue would only be half a solution. The guidance problem of the piston would also need to be addressed. With only half an inch to work with, there would not be enough room for both an effective seal and wear ring/bearing in two separate grooves.

In order to fully utilize the space available, Eclipse chose to combine the seal ring and wear ring into one unit, housed in the same groove. The center of the ring would be acting as the energized sealing portion activated by an O-Ring underneath. This segment of the seal cross-section would be thinned out to both control O-Ring squeeze and energy transfer.

The edges of the seal ring would be thicker and supported by portions of the groove in the hardware. These sections would act as the bearing surfaces. The stepped-down groove in the hardware would accomplish the desired tasks of both containing the O-Ring and acting as bearing surfaces.

How It Performed

Eclipse’s Seal-Bearing combination proved to be just what the customer was looking for. Wear-life and piston movement consistency were both greatly improved. Unexpected pauses in production to replace the O-Ring were virtually eliminated. Seal replacement could now be performed on a schedule that was at a much greater interval than ever before.

The bearing portion of the seal also proved to do its job. With proper guidance of the piston, metal to metal contact would no longer be an issue. The customer could safely run the machine at full production levels without fear of damaging the cylinder bore and incurring costly downtime.

This was all done with only a minor modification to the customer’s current piston design that they easily incorporated. Without any major changes to the design, the machine functioned properly as intended for long extended runs.

The Seal-Bearing combination is an example of Eclipse’s engineering ingenuity and years of experience put to work. While sealing challenges come in all shapes and sizes, limited hardware space for a seal can often be quite difficult. Eclipse is always up for the next test of engineering fortitude.

Need a seal in a tight spot? Have an underperforming seal and can’t change your hardware? Forget you needed a seal at all? We’re here to help you with whatever challenges you face.

Fill out a Project Request Form >

What You Should Know About Pressure-Velocity (PV)

Tue, 26 Jan 2021 14:18:00 GMT

When it comes to designing dynamic seals, the two most important application parameters are the pressure and the speed of the motion. These two factors chiefly determine the type of seal, design geometry, and seal materials you should choose.

When dynamic speeds and system pressures become elevated, determining the life expectancy of the seal becomes an important point of analysis. A seal that’s low friction, cost-effective, and seals outstandingly are useless if it only lasts a few hours before wearing out.

To quickly gauge the feasibility of a seal’s performance and provide a baseline metric, seal engineers use a calculation called Pressure-Velocity (PV).

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What Is PV?

Simply put, pressure-velocity is the product of pressure and velocity. In other words, the pressure of the system is multiplied by the surface speed of the dynamic seal interface.

To produce a value that’s consistent for comparison throughout the industry, the units used to express the pressure and speed are important. In the US, pressure is always calculated with PSI and surface speed in feet per minute.

The first step in calculating the PV is determining the surface speed of the system. In a rotary application, the diameter of the dynamic surface and RPM are needed. In reciprocating, the stroke length and cycle rate are required.

Once the surface speed is known, simply multiply it by the system pressure.

Example PV calculations:

Why Is PV Important?

PV is used as a quick gauge of the plausibility for the success of a sealing system in a given application. The exact value itself is not of tremendous importance, but it provides a relative idea of the stress and projected wear life of a seal.

How fast a seal will wear is a function of both the surface speed and pressure of the system. Sanding a piece of wood with some sandpaper serves as a good analogy: You’ll wear away more wood by either sanding faster or pressing harder. Doing both results in the maximum wear rate.

This is essentially what happens at a microscopic level to a sealing element. High pressure and high-speed result in a high wear rate. Once a sealing lip or element is severely worn, positive contact with the sealing surface will be lost resulting in leakage.

In high-pressure applications, structural integrity of the seal might also be compromised.

So assessing wear rate potential of a system is important.

PV considers both pressure and speed to provide a practical and quick evaluation for reference.

PV Values

PV is generally not discussed until values become elevated. It’s most often used for rotary applications. While pressures in reciprocating applications can be quite high, it’s much more difficult to generate significant surface speed, unlike rotary applications.

PVs of less than 30,000 would be considered mild and most typical catalog sealing solutions should operate at nominal performance and life expectancies.

The most referenced PV limit is usually 100,000. At this value, the transition between nominal wear and high or severe wear occurs.

There are many application-specific factors that will determine the PV limit of a system.

Temperature, lubrication, hardware finishes, and runout all contribute to the wear limit of the sealing system. A PV of 100,000 is not simply the end of the story — it’s typically the value that will get the attention of any seal designer.

A PV of greater than 200,000 is of immediate concern. This is considered the “severe wear zone” for a seal operating in those conditions.

If a customer presents Eclipse with a sealing application with this kind of PV, further discussion about the life-expectancy goals of the system is in order.

Eclipse has designed and manufactured successful sealing systems for PVs as high as 300,000. But at these levels, what one customer considers successful might be very different from another. Wear life of a seal under these conditions will likely only be a few hours.

Not All PV Is the Same

Clever readers might have realized that it’s possible to produce the same PV through different combinations of pressure and velocity. As demonstrated below, three very different operating and application parameters can all generate the exact same PV value.

This is important because the optimum type of seal in each of these situations will be totally different. A seal cannot be chosen based solely on PV alone.

Here’s a look at the different applications for PV pressure and the best seals to use for each:

High RPM, Low-Pressure Applications

Medium RPM, Medium Pressure Applications

Cased Spring Energized Seals , O-Ring Heel , and O-Ring OD Spring Energized Seals are best suited for this application. When pressure exceeds the limits for rotary lip seals, but surface speed is in check, these can be a good choice.

Eclipse’s in-house manufactured Canted Coil spring is usually employed for precise friction control and consistent loading.

Low RPM, High-Pressure Applications

Rotary Seal Rings are the seal of choice. Standard designs can handle pressures up to 4,500 psi. A specialized friction coating is applied to the O-Ring/Seal interface ensuring anti-rotation. These seals are often found in rotary unions transmitting hydraulic fluid or air.

Pressure Velocity Further Explained

Determining the pressure velocity of your application is integral to its success and the lifetime of the seal you’re using. By gaining some basic background on PV, you’ll be better equipped to work your way through the seal design process.

Eclipse’s team is dedicated to finding the right sealing solution to every application and educating others on the inner workings of the seal industry.

Our Engineering Manager, Chris Gruner, gives a quick math lesson on how to calculate pressure velocity. Once you understand how it works, it can be a quick and valuable way to decide what type of seal is needed.

Watch our video and learn more with Chris Gruner >

Crimped Case Seal or Componentized Design?

Fri, 11 Dec 2020 08:52:00 GMT

If you have an application with a rotating shaft, you likely need a seal. Rotary shaft seals often take the form of what is commonly known as an “oil seal.”

These usually consist of an elastomeric sealing lip, with a molded-in-metal case to facilitate a press-fit into the hardware.

Oil seals are typically mass-produced, and are usually available from stock in a variety of sizes. They function best in oil-lubricated environments, such as engine crankcases or gearboxes. But in dry running applications, you may need a PTFE-based sealing element.

In addition to not needing lubrication, PTFE lip seals provide a number of advantages over elastomeric oil seals. PTFE’s ability to handle much higher temperatures means higher rotational speeds can be achieved.

High-wear fillers can be added for much longer service intervals when compared to elastomers. Friction characteristics will also be far superior therefore lowering torque requirements.

As more and more modern applications turn to electric motors rather than internal combustion engines, the need for low-friction, dry-running rotary shaft seals is growing.

Most motors require an environmental shaft seal to keep dust, water, and debris from entering the internals.

There are 2 main designs for incorporating a PTFE seal element into a metal case. The first is what Eclipse calls their Crimped Case Seal (CCS). The second is the more traditional componentized design.

Both have pros and cons. Below, we’ll discuss what applications might better suit one design over the other. With the ability to offer either design, Eclipse is here to provide you with the best solution possible.

The Crimped Case Seal

In terms of seal history, the crimped case seal, or CCS, is a relative newcomer, entering the market about 10 years ago.

The crimped case seal’s hallmark design feature is that it can use as little as 2 components: the sealing lip and case. This is in contrast to a traditional design that usually requires 4 components to accomplish the same task.

A CCS functions by having the seal element slip into a small groove in a machined case. The groove is then crimped or compressed to positively engage the PTFE for both internal sealing and element anti-rotation.

This eliminates the need for an internal gasket element, affording maximum temperature handling, and chemical resistance.

The seal lip can be any one of Eclipse’s PTFE blends. Eclipse can tailor the material selection to optimize the goals of the system.

The case can be either Aluminum or Stainless Steel, but Aluminum will provide more size options and typically cost less.

Pros of the Crimped Case Seal

Other than fewer components, the CCS has some key advantages over a componentized seal.

First, the case of a CCS is CNC machined. This means the highest tolerance control and no expensive first-time tooling costs.

This can significantly improve lead-time compared to operations requiring tooling or dies. The crimping of the case is a simple procedure that can be done quickly on a press, rather than a more complicated forming procedure done on a lathe. This can further expedite lead-times and run rates.

The seal lip itself is also machined into its final shape. This allows for precision interference control and eliminates the need for the forming and shipping of the seal on a separate mandrel.

There are some limitations to the CCS though. While there are some great advantages to machining the seal case, this can also be a drawback in high volume applications.

The componentized design will have the option of stamping or rolling, forming the metal constituents from sheet stock, which greatly reduces unit cost.

Cons of the Crimped Case Seal

There are some size restraints to the CCS as well.

It’s not possible to install a lip into a case much smaller than 1.5.” On the upper end of things, it’s difficult to find raw metal tube stock in diameters above 12 inches with limited options above 6 inches. It might not be practical to machine a case with an OD in this range.

With these aspects in mind, the CCS is best suited for low volume, and/or quick turnaround applications with shaft sizes from 1.5 to 5 inches. Eclipse also successfully employs crimped case seals in very torque and friction sensitive applications, such as robotics.

Precise control of the lip profile and interference is necessary to provide smooth and accurate movement and seal volumes are relatively low. Prototyping seals without tooling costs is also a plus for numerous design iterations.

The Traditional Componentized Design

The traditional lip seal design has been around for decades and has seen service in countless applications and industries.

In the most basic form, it consists of are the outer metal case, the PTFE sealing lip, a thin elastomeric gasket, and a spacer ring.

The components are stacked and a small portion of the outer case is rolled over, usually on a lathe, to compress and permanently hold everything together.

The sealing lip can be any of Eclipse’s PTFE blends. It’s machined and assembled simply as a straight, flat disk. This means quick run-rates during machining and minimal raw material usage aiding in low unit costs.

The lip must be formed after assembly. Typically, this is done by pushing it on a cardboard mandrel that is just under the shaft diameter.

Cases and spacers can be Aluminum, Stainless Steel, or cold-rolled steel. Stainless steel is the most commonly used outer case material, and Aluminum is typically used for the spacer.

The gasket serves to provide some spring force to compress and hold the components, but also internally seals the inside of the case. It’s usually made of standard O-Ring-like materials, such as NBR and FKM. The use of specialized high-temperature reinforced NBR is also common.

Pros of Traditional Componentized Design

The chief advantage of this design is the ability to economically mass-produce the components. In particular, the metal components can be stamped from sheet metal.

This of course requires die tooling, which can cost thousands of dollars. But at higher volumes, the tooling costs are usually easily amortized, and the resulting unit costs are a small fraction of a machined component.

For slightly lower volumes, spin forming the case and spacer is an option. This involves forming a flat disk of sheet metal over a mandrel while be spun on a lathe.

While still requiring tooling, it’s often much less expensive than stamp die tooling. Spin forming is often used to form large-diameter cases, where raw billet stock is not available or practical for machining.

Eclipse Has You Covered

Both the CCS and traditional rotary lip seal have advantages and disadvantages, and specific application parameters will determine which design is best. The volume of seals needed will be one of the largest deciding factors in which is best for your specific project.

Eclipse can design and manufacture either seal from volumes of one to tens of thousands. We have full design and manufacturing flexibility in whichever option fits your needs.

Unlike some suppliers, Eclipse won’t obligate you to choose only one solution. We have many customers with legacy applications that use the traditional componentized design, but they may only need a handful of seals every year.

We’re happy to machine every component, and to avoid any tooling costs. Contact us today with your rotary lip seal needs >

How We Design a Seal from Start to Finish

Wed, 25 Nov 2020 10:22:00 GMT

We recently wrote about processing PTFE, or Teflon, from the drum of raw material to a finished rod or tube . But what’s involved in creating a seal from inception to completion?

We receive literally hundreds of requests a month for a seal or related product. Some never get past the inquiry stage, as the clients’ need doesn’t fit our specific products. In those cases, we may locate a source or suggest an alternative to what they’re looking for.

But there are many other cases in which we have the capabilities to fulfill our customers’ specific needs.

Below, we’ll outline the steps we take to turn our customers’ ideas into a finished part, along with the unique challenges brought on by COVID-19 and the adjustments we’ve made to stay on schedule.

Step 1: The Sales Department

A typical request will start out in our sales department, where the salesperson determines the best course of action based on the information the customer has supplied.

The better the information, the higher the probability that the first designed product works for the client.

Step 2: The Engineering Department

The idea then travels to our engineering department, where the idea is put on paper (electronically speaking). A price is generated based on annual usage, along with prototype pricing.

This package is then presented to the customer for evaluation. Customers generally have many questions at this stage, which are generally handled by the salesperson and/or the engineering staff.

Step 3: Ordering the Prototype

Once the package has been approved, it’s time to order the prototype. Our goal is to keep the part as close as possible to a production part.

On a machined part, this is usually a simple task. But for a part that may require tooling in production, we’ll often machine a part that may get stamped in production. This keeps cost down, but doesn’t exactly mirror production.

At this stage, we prepare the final manufacturing drawings, along with production routing to ensure we mirror a production process. Materials may need to be specially ordered to fill the prototype order.

Lead times are then set, and the job traveler is printed with all the required steps. During this process, a quality audit is conducted to ensure the sales order is complete, and correct documentation for the order is staged while the order is being processed.

Step 4: Receiving Raw Material

Once we receive the raw material and verify the quality records, the material then goes to the floor where it’s matched up with the job and traveler.

The job is placed in que with the material and any special tooling for the job. When the job comes up, it’s matched with the material and flows to the floor for production.

We review the quality paperwork to ensure we have all the data we need to properly process the product. Finally, we set up the machine and run the first article, along with paperwork validating conformance to the customers’ requirements.

Step 5: Running the Job

At this point, we’re ready to run the job and create the product. We complete any final paperwork (including any inspection paperwork), and parts either go to shipping or to second operation for the addition of coatings, a spring, etc.

The same quality paperwork is completed at each process to ensure each step is complete.

Step 6: Shipping

The finished product moves into shipping, where we once again complete the proper quality paperwork, along with a review of required customer documentation.

We may need to consider special packaging needs as the product is prepared for shipment, per the customer’s requested method. The package is equipped with a shipping label, a packing slip, and any other documents required by the customers receiving department.

Step 7: Invoice and Scanning

Finally, the order moves to accounting for invoice and scanning.

Scheduling Issues During COVID-19

Since the onset of COVID-19, we’ve had to deal with many scheduling issues due to our employees being exposed to the virus, or their children’s schools going virtual (requiring employees to stay home and look after their kids).

This year, we’ve also received an increase in expedited orders from customers at a rate we’ve never seen before! While our doors are rarely closed, the challenges around navigating the virus in addition to extra expedites have tasked us with finding ways to stay on schedule for our clients.

Changes to Expedited Orders in 2020

We always leave room in our schedule for expedites, as we understand some jobs are more critical than others.

There are 2 major components to expediting a job:The first is that we must receive the raw material quickly. The second is that all the other jobs that were in place prior to the expedited order are shifted back.

To stay on schedule, we’ve been working overtime to keep all our clients’ orders moving forward.

We’ve been employing machines that are more cost effective to run for particular jobs. Running on a machine that is less specific usually slows the run rate, thereby increasing cost of the part.

Keeping Our Customers Up and Running

Our goal is to always ensure our customers’ equipment continues to operate without interruption.

When a production order arrives, the job has already been planned, programed and routed. All that’s left for a long running job is raw material and scheduling.

In a perfect world, we would run the prototype exactly the same as the production part, using the same equipment to run the job. But a new customer requires a slightly different cycle, as there’s usually some accounting on the front end to open an account. And more importantly, there’s more time spent on the back end when it comes time to ship.

Learning the habits of a new customer generally takes a few cycles. We understand that by properly packaging and shipping your product, we can make the acceptance of your parts to go much smoother.

Improving Our Production Processes

On top of all the challenges of 2020, we’ve been working to improve our production processes with better techniques and special equipment meant to help run a particular job.

And in the background, we have a staff ensuring we comply with various regulations and with ISO 9000, which was implemented over 10 years ago.

Our entire system is based on what we can do to make the entire seal design process as seamless as possible.

Over 20 Years of Seal Design Experience

Design is at the center of everything we do here at Eclipse Engineering. We realize parts don’t simply fall into your hardware.

When your parts do arrive in the mail, we’re ready to help with installation, including designing specialty tools customized to meet your hardware needs.

We’re often on the front line explaining what we feel is the most cost effective method to install in production. If you ever have any questions about your parts or design, you can always give us a call.

Contact Eclipse Engineering for all your polymer, seal and bearing, and rotary needs >

The Best Way to Process Teflon® (PTFE) for Optimal Seal Performance

Tue, 27 Oct 2020 19:52:00 GMT

Below, we’ll explore how Teflon is processed for sealing purposes, and why we sometimes see variation in surface quality and/or cracks in finished Teflon seals.

The Two Ways to Process Teflon® for Seals

There are different grades of Fluoropolymers that can be used to manufacture seals. There are melt processable fluoropolymers, which are rarely used in the seal manufacturing process due to cost, and granular PTFE.

Melt processable fluoropolymers allow for injection molding, and exhibit many of the same characteristics as granular PTFE. But the first grade doesn’t allow for the flexibility of molding and machining, which is why most of our seals are made from granular PTFE.

Milling Granular PTFE for Seals

All granular PTFE starts out as “standard flow” which means it’s the consistency of flour. While it can “flow” into a seal mold, it pours much like flour, which can be clumpy.

Standard flow can be blended with fillers to help improve some physical properties, such as wear, but can degrade tensile and friction. Tensile strength is usually not a problem, as most seals are in compression.

Fillers will increase friction slightly. When fillers are mixed, or blended, into the base resin, they’re milled to ensure uniform dispersion within the compound that’s being created.

During this milling process, the mixture begins to get warm. Keeping the temperature low ensures that the fillers can be uniformly dispersed within the mixture.

If the temperature does rise to the point in which the compound will no longer flow in the mill, clumping can occur. Materials will generally have multiple passes through the mill, but too many passes will begin to degrade the physicals in the base resin.

Allowing the compound to rest after filling will allow the bulk temperature of the compound to return to room temperature. This helps the molder pack the material into the mold.

If the compound is too warm during the molding process, voids can form in the mold, which will result in cracking in the seal.

Molding Granular PTFE

There are 3 basic methods to create a rod or a tube: Compression molding, isostatic molding, and automatic molding. All 3 have pros and cons, but all 3 can yield a seal that is functional in most applications.

Physical properties will vary between the 3 methods. These variations are normally inconsequential, but if extrusion is a problem due to high pressure, one method may perform better due to a variation in molding creating lower physicals of the material.

For the purposes of this article, we will assume all methods yield good material. Automatic molding is generally done using pelletized material, which is referred to as free flow.

The molding process is a 2-step process. Packing the mold and pressing the powder in is referred to as the “green state.” This is then followed by sintering to alter the molecular state of the compound.

After packing a mold and pressing the material to 3000 PSI, the material is then removed from the mold. This removal process is a critical procedure while the compound is in the “green” or un-sintered state. Any mishandling of the green material will result in cracks.

The demolding process must be done with care as to not disturb the material as its removed from the mold. Green material is often placed on carts that move the material to the oven for sintering. But movement over uneven floors has been shown to induce cracks in the material.

Sintering Granular PTFE

The sintering process results in a change in the compound, allowing the molecules to reorganize. This process makes this material a compound as opposed to a mixture, and cannot be broken back down to its original constituents after sintering.

There is a science to proper sintering of PTFE. But to summarize, this process is done between 675 and 700 degrees Fahrenheit.

Sintering must be done in an oven to insure good airflow. Rods and tubes must be situated to insure they don’t sag in the oven.

A proper oven cycle will ensure the material is properly sintered, which usually includes an annealing cycle to help physicals and stop cracks from forming.

After cooling to room temperature, the material is ready to be machined.

Free flow is a secondary process that pelletizes the material, allowing it to flow into the mold more easily. It lends itself to automatic molding due to the non-clumping of the material.

Physicals from free flow will generally be lower than standard flow. But the molding process may often bring material physicals close to the standard flow.

Automatic molding allows for thinner tubes, which results in a more even pressure distribution within the material. Thinner tubes allow for less waste of material, and quicker machine time.

Automatic molding often allows for the autofill of the material into the mold, saving manufacturing costs. Automatic molding may also result in surface finish issues on the finished part.

In most cases, this mottled look isn’t an issue — it’s simply due to the pelletized material as opposed to standard flow where particles may be closer together.

How to Avoid Cracking in Granular PTFE

In general, the processing of granular PTFE results in excellent parts for a wide variety of sealing applications.

There are many steps in the process that may result in some form of cracking of the finished part. These cracks are normally found in the manufacturing process, or upon installation.

There are special methods of crack detection for granular PTFE, and these methods are generally costly. But the incidence of cracking is generally so small, it’s not cost effective to test or preform special processes of detection.

Any deformation of the ring normally results in a failure of the ring.

At Eclipse Engineering, our quality department and manufacturing staff are trained to look for signs of cracks in unfinished rods and tubes, and in finished seals. We almost always find most cracks prior to shipment, so you can rest assured you are being delivered the best sealing product possible.

PTFE in O-Rings

While most common O-Ring materials are rubber or elastomeric compounds, certain operating conditions and hardware configurations merit the use of PTFE as the material. And while PTFE offers some distinct advantages over elastomers, it also has some draw-backs that can negatively affect seal performance.

Here’s how to determine whether a PTFE O-Ring or Spring Energized seal is the best for your application >

The Advantages of a Canted Coil Spring Energizer

Mon, 05 Oct 2020 17:36:00 GMT

When considering polymer jacketed seals — especially PTFE-based products — some form of energizer is typically required. These types of seals are usually specified to operate both in very high pressures, low pressures, or even in a vacuum.

At some pressure (typically above 100psi), the system pressure will energize the seal and prevent leakage. But at low pressures, additional energy is required to force the jacket material to mate with the hardware.

The solution to this is to add a spring to the seal. The spring provides the needed sealing-energy to prevent leakage at low media pressures.

When considering a high pressure-application, there are start/stop conditions where the system is at low pressure. If the seal allows some amount of leakage at low pressure, it becomes possible for that leakage level to increase once as the pressure builds.

This phenomenon is called “blow-by.” Once it occurs in a system, it’s difficult to get the seal to seat and seal correctly.

Canted Coil Spring Energizer

There are several types of energizers to consider when specifying a seal. These can be as simple as an O-Ring or some other elastomer.

We most often recommend a metal energizer such as a garter, cantilever, helical, or canted coil spring . The canted coil spring offers some very interesting properties that other springs don’t display.

Once the canted coil spring begins to be deflected, it has a relatively flat force curve in the middle of its travel. This allows the designer to have a consistent load over a very broad deflection range.

This spring type is also resistant to damage unless it’s stretched. Unlike cantilever v-spring or helical spring which can be yielded and take a set when over-compressed, the canted coil is almost impervious to this. A hard stop will be reached once the coils are “butted” preserving the spring functionality.

Canted Coil in Seals

In seals, the canted coil spring is used to force the lips of a polymeric or elastomeric seal out. This causes the seal to always be in contact with the sealing surface supplying contact force for low pressure sealing.

Another key factor is the ability to control the load where friction forces need to be kept to a minimum. As the seal wears, with a relatively flat load curve, those friction forces will remain at the desired level throughout the life of the seal.

Eclipse designs and constructs all the necessary fixturing and tools to facilitate the cutting and welding of canted coil spring for use in seals. Eclipse takes no shortcuts in seal manufacturing as all our springs are fully welded before being installed in any seal.

Our canted coil is welded using our state-of-the-art laser welder ensuring a very small, accurate, and strong weld.

Canted Coil in Detent Mechanisms

Another aspect of canted coil spring is its advantages in detent mechanisms. This is very useful where a reusable lock is required between two moving components.

A groove is machined in both parts, and the energy of the canted coil retains and soft locks the parts together. This allows for nearly limitless lock / unlock cycles to be possible.

Canted Coil and EMI Shielding

The canted coil spring can also be used to create EMI (Electro Magnetic Interference) shielding between two metal components. With a change in material, these springs can create the type of shielding necessary to reduce or eliminate EMI from other sensitive electronic circuits in a piece of equipment.

A variation of this is using a canted coil as an electrical conduit where coupling connections needs to be made.

Metallic energizers can be made from a wide variety of materials. The most common one being 300 series stainless steel.

For chemical resistance, Hastelloy and Elgiloy are commonly found in the oil drilling applications to handle high heat and Hydrogen Sulfide, a highly corrosive gas.

Eclipse Excels at Energized Seals

Eclipse Engineering has been manufacturing elastomeric and metal spring energized seals for over 20 years. With our ability to create tools in house, we have the capability to manufacture seals that are under 1/16 inch up to in excess of 50 inches in diameter.

Creating custom springs including photo-etched cross section springs are all available to the designer today at relatively low cost even for short runs. Learn more about our canted coil spring seals >

How To Design The Perfect Seal For An Accumulator

Thu, 03 Sep 2020 16:55:00 GMT

An accumulator is an apparatus for storing energy or power. This is an obsolete term for a capacitor, which is commonly used in electrical engineering.

In hydraulic systems, we use accumulators for two very specific purposes:

A good example of this is when a crane is slewing, and the operator wants to move the load very slowly without jerking it around. Hydraulic gear motors and pumps often create pulses that an accumulator will absorb and thereby not transfer those pulses to the load where a welder may be setting a beam on a building.

Common Types of Accumulators

There are two common accumulators:

Both accumulator types use nitrogen gas as the energy-storing or shock-absorption method, but both work dramatically different.

Bladder Style Accumulator

The bladder-style accumulator has a rubber bladder inside a rounded-chamber, with a Schrader valve sticking out of the chamber on one side.

The other side contains a type of hydraulic fitting arrangement, which allows you to connect a hydraulic line to the device. This style looks a little bit like a bomb to allow the rubber bladder to not crease within the device.

The bladder is normally filled with nitrogen gas. This pressure can vary depending on the application, but oftentimes sits between 500 and 1000 psi nitrogen gas.

Without hydraulic fluid in the system, the entire bladder fills the cavity. When a hydraulic source is attached and exceeds the pressure in the accumulator, the rubber bladder acts as a hydraulic spring, absorbing shock waves within the hydraulic system over the pressure of the static accumulator.

Uses of Bladder-Style Accumulators

Many homes use an accumulator in their water systems to stop “water hammer” — that clang you might hear when you shut the water valve too quickly. The accumulator absorbs that shock in water.

In the earlier example of a crane slewing, it’s the combination of the teeth in the gear motor and pump that cause the vibration felt at the end of the load. Oftentimes, some well-placed, high-pressure hoses in between all the rigid tubing in the hydraulic system will accomplish the same task the accumulator does.

Thus, the bladder-style accumulator is excellent for shock absorption.

Piston-Style Accumulators

The second common style of accumulator is the piston accumulator. This device is usually intended to store energy, and release that energy on-demand.

Because this is typically not a momentary device, the amount of energy is taken up by the displacement of a piston in a long tube where the “piston” is used to compress the nitrogen gas.

This compression causes the gas pressure to rise above the initial pressure, and thereby stores the energy until a valve is opened, allowing the compressed nitrogen gas to force the piston down the tube. This in turn forces the hydraulic fluid to move from the tube and exert energy.

Use of Piston-Style Accumulators

Calling back to the example we used earlier about needing to lower landing gear, the accumulator needs to have enough travel to move the stowed gear in the up-and-locked position into the down-and-locked position.

The length and diameter of the accumulator must at least match the volume necessary to extend the gear with a margin of safety. There also needs to be enough pressure from the system to cause the gear to lock into place at the bottom of the stroke.

Since the piston-style accumulator is a dynamic device, the piston will be required to move rapidly down the tube without scoring the tube. Unlike the bladder accumulator, the piston-style will require dynamic seals on the piston to allow it to maintain nitrogen pressure in a dynamic state without leaking the nitrogen to the hydraulic side.

This is a bit more complicated than the bladder, which is a single membrane.

The piston must be able to move quickly with low friction, and will generally requires some kind of rubber contact to hold the nitrogen gas from leaking into the hydraulic system.

Eclipse Accumulator Seals

At Eclipse , our seal engineers design a “Q” seal that uses a Teflon element as the piston seal, with a combination of rubber energizers and an “X” ring in the middle of the Teflon piston seal to stop the flow of gas across to the hydraulic side.

This combination allows for rubber contact against the nitrogen. Nestling the X ring within the Teflon seal lowers the force of the X ring on the bore, keeping friction and heat to a minimum.

A set of Teflon wear rings on both sides of the Q seal allows the piston to “float” without scoring on the bore of the tube. There should be no side loading in this design, and keeping the piston centered in the bore protects the sealing surface against scratches which would allow the nitrogen to eventually leak out.

Eclipse Seals in Modern Day Aircraft

Like accumulators, another crucial hydraulic system seal can be found in aircraft. This system controls the brakes, suspension, flap actuators, landing gear, and more. These systems undergo extreme amounts of stress, especially during take-off and landing.

The types of custom seals our seal engineering specialists create for aircraft hydraulic systems are made of durable polytetrafluoroethylene, otherwise known as PTFE, or by its household name of Teflon.

Learn more about Eclipse seals ’ role in aircraft construction >

How to Design the Perfect Rotary Shaft Seal

Tue, 01 Sep 2020 15:20:00 GMT

When it comes to maintaining a high-functioning rotary shaft, you need to select the appropriate lip seal.

The shaft seal protects the rotary shaft from contaminants such as dust and dirt , and it keeps water out and lubricant in.

A rotary seal, also known as a radial shaft seal, typically sits between a rotary shaft and a fixed housing — such as a cylinder wall — to stop fluid leaking along the shaft. The rotary seal’s outside surface is fixed to the housing, while the seal’s inner lip presses against the rotating shaft.

Common applications for shaft seals include motors, gear boxes, pumps and axles. They’re also increasingly used for food and chemical processing, as well in pressurized gas applications.

Three of the most important considerations when the choosing the best lip seal for a rotary shaft are:

Here’s our guide on how to achieve optimum performance and longevity for your seals and shafts, ultimately minimizing the risk of seal failure.

What Material Is Best for Rotary Seals?

The standout material of choice for a rotary shaft lip seal is polytetrafluoroethylene, also known as PTFE. This material is commonly used in seals because of its extremely low friction and resistance to wear and tear.

It also performs exceptionally well at high operating temperatures, requiring minimal lubrication. Plus, it is compatible with many chemicals, making it a good universal choice.

Rotary shaft lip seals made of PTFE are very tough and have a low coefficient of friction, which allows them to slip over the highest points of the mating surface (in this case, the rotary shaft) while resisting abrasion. And they can do it without lubrication.

Which Properties of Metal Rotary Shafts Most Affect Sealing Performance?

The roughness and hardness of a metal rotary shaft are the two most important characteristics to be considered when designing a lip seal for the shaft. Let’s look first at roughness.

What is Roughness in a Rotary Shaft?

Roughness, in the context of a rotary shaft, refers to the unevenness of the surface of the shaft. The way we measure shaft roughness is by measuring the high and the low points of the shaft’s surface, then calculating the difference. This is called the machined tolerance.

Roughness can be minimized by properly finishing the surface of the shaft. A well-finished surface with an appropriately machined tolerance will allow for excellent seal performance, as well as longevity.

A rotary shaft with a high surface roughness can allow paths for leakage through the low points on the shaft’s surface. The abrasiveness of the surface can also wear down the seal quickly, leading to failure.

Generally, the smoother the rotary shaft surface, the better the seal will perform. However, excessive smoothness beyond spec can actually decrease the effectiveness of a seal. This is because in extremely smooth surfaces, a film of lubricating fluid is not allowed to flow between the seal and the mating surface.

The passage of this film lubricates the seal and extends its longevity. Without it, the seal will wear out sooner. Essentially, if your rotary shaft’s surface is too smooth, a seal will perform too well — until it doesn’t.

What is Hardness in a Rotary Shaft?

The hardness of a rotary shaft is measured by looking at how deep an indenter can penetrate into the surface of the shaft when forced upon it at high pressure. Using a Rockwell scale, we can measure the penetration depth relative to that made by a reference pressure.

A seal should always be softer than the rotary shaft. This ensures it wears out instead of the shaft. So the harder the shaft, the more options you have for seal material.

In metal rotary shafts, the harder the surface, the better. Increased hardness allows for the use of highly reinforced seal materials, which will increase the lifespan of both the lip seal and the shaft itself.

The alternative, a softer metal shaft, is susceptible to abrasion and erosion from the best seal lip materials (PTFE). So when you’re working with a soft rotary shaft, you need to use a softer seal. This is a workable solution, but it does mean you’ll be stuck with a shorter seal life.

There is, though, one advantage to keeping rotary shaft surface hardness below 45 on the Rockwell C scale, and this is that most seals will actually polish the shaft surface during the initial “bedding in” period.

After that period, the wear upon the rotary shaft will ease off, depending on the PTFE material of the seal, the shaft’s surface finish, and Pressure*Velocity (PV rating) of the application.

When hardness exceeds 45 Rockwell C, the initial manufactured surface finish is absolutely crucial to seal life. Why? Because there is not much polishing allowed for in the “bedding in” period. When hardness is high, any roughness in the surface will cause wear on the seal.

So as you can see, the roughness and hardness of the surface of the rotary shaft are not independent properties when it comes to lip seal design — as the hardness goes up, roughness needs to go down. Alternatively, a less hard surface allows for a bit more roughness.

What is the Recommended Hardness for a Rotary Shaft?

The ideal hardness for a metal rotary shaft depends on shaft speed and environmental pressure.

In typical engineering practice, the hardness used is normally a compromise between the expense of harder finish metals and seal life. As with any design task, the challenge is finding a solution that meets not only the technical requirements, but also falls within the logistical (i.e., budgetary) limits.

Achieving the Optimum Match Between Rotary Shaft and Lip Seal

Because of the wide range of PTFE fillers and material specifications, it’s not always easy to find exactly the right rotary seal for your shaft to ensure optimum seal effectiveness and longevity.

If you can’t find an existing shaft seal that meets your needs, you may need to design a custom seal. That happens to be exactly what our seal engineers specialize in here at Eclipse Engineering. We craft many types of seals for rotary shaft applications. including cased lip seals, O-ring OD lip seals, and MicroLip seals .

Find the right rotary seal for your application >

How To Make Seals That Keep Dust Out Of Equipment

Thu, 23 Jul 2020 18:17:00 GMT

Dust is typically a minor annoyance that haunts the surfaces of our home. But in the world of engineering, machinery, and mechanical systems, it can be the difference between a reliable piece of equipment and disaster.

Dust can cause major damage to cylinder walls, rods, seals and other components inside of machinery. And if you’re not careful, dirt, mud, debris and water can all cause damage as well.

These foreign contaminants are real problems for mechanical systems, especially as they build up in small quantities over time. A single particle of dust today may be no big deal. But a mote of dust a day will eventually become enough of a presence to cause serious issues, like friction, surface wear and imperfect seal contact between surfaces.

These issues could compound until the mechanical system experiences a complete failure. It may seem like perfect is impossible, and that eventually some contaminants will get into your system no matter what you do.

But in some applications, like in automobiles and aircraft , failure is simply not an option.

Beyond those industries, many types of equipment need to stay clean on the inside, even when things get extremely messy on the outside. Examples include earth movers, hydraulic cylinders in steel mills, snow plows, and metal foundries, and in seals in logging equipment.

How to Keep a Mechanical System 100% Dust-Free

Just as seals keep pressurized fluids and gases in piston and cylinder systems, there are components that are designed to do the exact opposite — keep contaminants out .

In the sealing industry, the three main types of components used to keep dust at bay are wipers, excluders and scrapers. While each are a bit different, they all serve the same basic purpose, and are fitted on the exterior side of the main seals in a system.

The exact type of dust-prevention mechanism you need depends on what exactly you’re trying to protect against.

1. Wipers

These are used for light applications to seal out fine material like water, dust and wet mud, and are made of soft plastic or firm elastomer (also known as rubber).

If your primary concern is easy assembly and low friction, wipers may be the right choice for your application.

2. Scrapers

This component type is used for aggressive applications to seal out hard stuff like ice, dry mud or other solid debris. Scrapers are made of hard plastic or metal, commonly brass.

Scrapers do have one downside: They’re not ideal for preventing finer material from getting in. They also allow piston and rod lubrication leakage, which attracts dust buildup. In these cases, you probably want to use a soft wiper in tandem with a scraper by attaching it to the inside of the scraper.

3. Excluders

These fall somewhere in between wipers and scrapers in terms of protection capability. Excluders seal out medium-level material, which makes them perfect for when you need something more serious than a wiper but not as high-functioning as a scraper. Oftentimes, they’re an ideal solution.

Excluders are commonly used in hydraulic cylinders. They prolong seal life by preventing contamination of the hydraulic fluid that would otherwise damage wear rings, seals and other components.

A typical occurrence in hydraulic cylinders is the leakage of a microscopic film of hydraulic fluid through the excluder onto the piston/rod on the out-stroke, which can then attract dust. But on the return stroke, the excluder rubs all of that away to prevent entry of the fluid (with its newly found dust) back into the system.

Excluders are useful for rugged applications, like keeping road dirt out of vehicle shock absorbers or mud out of brake cylinders.

You also find excluders in use in pneumatic cylinders, which are usually of lighter construction than hydraulic cylinders. This means that the excluder can be combined with the inner seal, all in one piece.

Since excluders are typically designed for low friction, with a rounded or chamfered profile, they can be used in pneumatic cylinders to allow for the return of any leaked lubricant.

The one problem with excluders being designed as one piece with the inner seal is that they don’t perform as well as a separate excluder. However, this design more than makes up for its flaws by allowing for a small amount of compressed air leakage, which blasts away any contaminants. The cylinder can afford to use a little bit of air more than it can afford to lose fluids.

Endless Options for Keeping Dust Out

Wipers, excluders, and scrapers are built in all sorts of combinations for unique needs and desired functional parameters.

At Eclipse Engineering, we can help you decide what kind of design is right for your needs, considering the contaminants you’re looking to keep at bay, installation specifications, and how much friction is acceptable.

We’ll also help you choose the appropriate materials for your solution. For example, a PTFE-encased stainless steel scraper can operate in temperatures up to 550 degrees Fahrenheit.

Learn more about our wipers, excluders, and scrapers and request a solution for your application >

Your Guide To The Pros And Cons Of PEEK Back-Up Rings

Wed, 15 Jul 2020 17:17:00 GMT

Back-up rings serve an important role in world of seals. While the design principle and construction are incredibly simple, they greatly extend the usefulness of the most common and prolific sealing device in the world: the O-ring .

Back-up rings are aptly named as they do just that: they back-up an O-ring.

Back-up rings are commonly nothing more than a ring of polymer meant to space the O-ring away from the extrusion gap in hardware. By blocking off the extrusion gap, the pressure-handling ability of an ordinary O-ring is greatly increased.

Solid or split back-up rings out of virgin PTFE can usually be found on the shelf, and are largely considered commodity items. Eclipse manufactures tens of thousands of back-up rings every year, for a wide range of industries.

While the design and functionality of a back-up ring rarely changes, the material selected can greatly complicate this simple device. Some applications require specific material properties and/or special material certifications.

Eclipse has the ability to manufacture military-spec back-up rings out of fully certified AMS 3678/1 virgin PTFE. If your application calls-out or requires a certified “MS” style back-up ring (MS27595 or MS28774), Eclipse has you covered.

We can also manufacture a back-up ring out of any of our long list of PTFE blends, thermoplastic elastomers, and urethanes. But other than virgin PTFE, the most common custom material for back-up rings Eclipse uses is PEEK (polyether ether ketone).

In certain applications, PEEK has some distinct advantages as a back-up ring material. But with these advantages comes some potential issues.

Read on if switching from a PTFE to a PEEK back-up ring sounds like an enticing proposition to see what you need to consider before making the change.

The Advantages of PEEK Back-Up Rings

In higher pressure applications, or when an O-ring must contend with a larger-than-recommended extrusion gap, a virgin PTFE back-up ring might not be enough to prevent extrusion.

If you’re experiencing sealing failures due to O-ring and back-up extrusion, it’s probably time to switch to a higher modulus back-up ring material.

Other than virgin PTFE, other common back-up materials that are more extrusion resistant are nylon and thermoplastic elastomers. Both materials will offer much better performance in terms of ultimate pressure handling when compared to virgin PTFE.

However, these materials present some limitations. nylon and thermoplastic elastomer both have an upper temperature limit of around 250°F, and might see reduced mechanical properties at around 200°F.

Diminished extrusion resistance means tighter extrusion gaps will be needed, something which isn’t always possible or desired. And if the application needs to operate in this temperature range, an alternative back-up ring material is needed.

Eclipse’s EP033 virgin PEEK has become a go-to for applications requiring a high-modulus and high-temperature plastic. With a durometer around 85 Shore D and an upper temperature rating of close to 500°F, PEEK is an optimum material for high performance back-up rings.

Industries such as oil and gas require demanding working conditions. Eclipse supplies PEEK back-up rings used in multiple down-hole drilling applications where pressures can be up to 5,000 psi and temperatures often approach 350°F.

PEEK is an optimum performer in these situations. It can function at the same level as a metallic back-up ring, without the risk of metal-to-metal contact which could potentially gall the hardware.

The Potential Issues in Using a PEEK Back-Up Ring

Eclipse often gets requests for PEEK back-ups from customers experiencing failures with standard dash number PTFE back-up rings.

Unfortunately, making a PEEK back-up to the standard “MS” PTFE dash number dimensions is in most cases a bad idea.

A standard PTFE size back-up made out of PEEK won’t work at all in a standard size static O-ring groove. It will prevent the hardware from assembling.

Dimensions for the standard dash sizes count on the PTFE being able to deform or distort to fit the hardware. If the back-up ring is slightly too big for the hardware it will “squish” into place without much effort.

Being a much higher modulus plastic, PEEK will not cold flow like PTFE. A ring wall even 0.001” oversized from the hardware cross-section will prevent hardware assembly or create assembly issues. The back-up ring needs to be correctly sized for clearance in the hardware.

If your application requires a PEEK back-up, we’ll need the rod or bore diameter, groove diameter, and groove width to properly design the back-up ring for optimal performance. Due to the wide variety of O-ring gland standards and specifications, simply asking for a PEEK back-up to use with an O-ring dash size isn’t sufficient information.

Another potential problem with split PEEK back-up rings is O-ring nibbling. This is where the split in the PEEK back-up will start eating away at the O-ring.

Pressure cycling or dynamic motion can cause the split to open and close slightly. The O-ring can protrude into the split, and be nibbled away by the hard, sharp corners. This typically is not a concern with PTFE and softer material back-ups.

One remedy for O-ring nibbling is to place a PTFE back-up ring between the PEEK back-up and the O-ring. The PTFE will protect the O-Ring from the split in the PEEK and eliminate nibbling. This will require extra axial gland width to accommodate the two back-up rings.

An additional consideration before ordering a PEEK back-up ring is certain installation situations for solid glands. A split PTFE back-up — except for the smallest diameters — likely will be able to be stretched or compressed to fit into almost any solid gland.

For example, it will not be possible to open or expand a PEEK back-up enough to fit directly into a solid piston gland without fracturing it. A PEEK back-up will need to be looped around the end of the hardware or fed in one end at a time in a spiral fashion, much like a metal piston ring.

Lastly, you should be sure to consider the cost before making this switch. Compared to an off-the-shelf PTFE back-up ring, a custom PEEK back-up will cost more.

A PEEK back-up needs to be designed to fit the hardware, so stocking standard dash numbers isn’t possible. Each job will need to be made to order and is subject to standard lead-times and minimums.

Contact Eclipse for All Your PEEK Back-Up Ring Needs

If your application is seeing failures or extrusion using standard PTFE back-up rings, PEEK might be just the alternative material you need. Eclipse is here to design and manufacture any of your back-up ring needs.

Contact us today >

The Story Of Seals In Modern Day Aircraft

Fri, 19 Jun 2020 16:27:00 GMT

In the last century, commercial air travel has transformed the way we see the world.

What were once far flung, distant lands can now be reached in under a day from anywhere across the globe. And the popularity of air travel only continues to grow.

It’s predicted that the number of airplanes in the sky will double by the year 2032 . That means in addition to the demand for more planes, the demand for faster, safer, and more reliable aircraft is driving the performance of new planes to levels never before seen or imagined.

Needless to say, the Wright brothers would be impressed.

But reaching the performance goals required by modern day aircraft designers and manufacturers is no easy task. New aircraft need to be lighter, more fuel efficient, and cheaper to fly than previous generations of planes.

The challenge lies in achieving a high performance, while maintaining a supreme degree of reliability and safety. There are a number of components that help to assure safety, and seals are one of the most important.

But what happens when a part fails to live up to the standards required by the aircraft industry? Disaster can start with just one faulty component.

What Happens When An Aircraft Component Isn’t Perfect?

Sometimes, the failure of a small component can initiate a sequence of events ending in catastrophic failure — like the Qantas flight QF32 taking off from Singapore in 2010.

A small stub pipe carrying lubricating oil to a bearing was machined by the manufacturer with unequal thickness, leaving it misaligned and fragile. When it broke, it leaked oil, which caught fire and softened the spinning turbine blades.

As a result, the turbine blades disintegrated and tore the engine apart. Shrapnel then punched holes in the wing, damaging spars and severing a main fuel line.

This example of a seemingly negligible issue — that of a slight difference in thickness — highlights just how crucial perfection is in the design and manufacturing of parts for use in aircraft.

Fortunately, the pilots managed to turn the plane around and land safely. But this easily could have been a far more dangerous and disastrous situation.

Modern Aircraft Performance Demands

When it comes to the cutting edge in aircraft design and development, aviation consultant and former National Transportation Safety Board member John Goglia claims that “we are pushing the technology faster than at any time in the past.”

The complexity of new aircraft is ever-growing. Elaborate electronics, fine trim systems, hydraulic-assisted control surfaces and improved engine mechanics all require precise components in order to function.

Even an old Boeing 737 would have had an extensive list of upgrades and part replacements in its life.

The industry now requires ever-extended lifespans and longer maintenance intervals for components such as flap actuators.

These demands of modern day aircraft may seem intimidating to some. But here at Eclipse Engineering , we meet these kinds of expectations every day with our custom seal design and manufacturing.

With precision engineering, use of the proper materials, and extensive, thorough testing, we’ve become a go-to firm for the aerospace industry’s seal needs. Our seals were even used on the Mars Rover !

Eclipse Seals’ Role in Aircraft Construction

Aircraft require a plethora of seals to contain pressurized fluids, exclude contaminants, retain lubricants and keep the body airtight. High-quality materials are essential to deliver these functions reliably.

We use high-specification elastomers in the creation of all our airframe seals, O-rings and molded parts in order to meet these demands.

One crucial aircraft component in which seals are essential are the hydraulic systems that control the brakes, suspension, flap actuators, landing gear and more. These systems undergo extreme amounts of stress, especially during take-off and landing.

The seals we create for aircraft hydraulic systems are made of durable polytetrafluoroethylene, otherwise known as PTFE, or by its household name of Teflon . This is the same stuff that makes your pots and pans non-stick.

It’s the low-friction property that makes Teflon the perfect choice for seals in hydraulic systems in airplanes. In this application, PTFE outperforms and is more dependable than any other material out there.

Achieving Ultra-Reliability with Eclipse

As the aerospace industry continues to rapidly develop, it will rely on quality suppliers to support it. A new aircraft usually takes about five years to develop, with a myriad of components to be designed and engineered along the way.

Increasingly advanced solutions are a necessity, and they’re under-girded by the most stringent quality regime of any industries.

It takes the highest quality parts to maintain efficient and safe operation. Precision and accuracy are critical, with machining tolerances getting tighter and tighter with each passing year.

Eclipse Engineering has in-depth experience with the rigorous demands of the aerospace industry, and offers a range of reliable top-quality seals for aircraft and ground-based aviation systems. These include spring-energized aerospace seals , elastomer-energized PTFE seals , and high performance elastomeric seals and O-rings .

The governing AS9100 quality standard specifies extensive requirements for product risk, documentation and product traceability, and it’s something we take very seriously . Thanks to these governing standards that we adhere to, if there is a sealing problem (something that is a very unlikely event), manufacturing can be traced back to the exact second of production, the machine, and the operator, assuring full accountability.

Looking for custom crafted, best-in-class seals for aircraft or ground-based aviation systems?

Contact us for a consultation >

Eclipse Announces MicroLip™ Prototype Program

Thu, 11 Jun 2020 18:15:00 GMT

While we have had some manufacturing downtime during the COVID-19 pandemic, we’ve been working on finding solutions to issues that our customers have brought to the table over the past few years.

We’ve sent many new designs into testing, and have been focusing on processes that will help improve productivity and lower costs.

When moving from rubber to Teflon lip seals , we found that the cost to bring the product to market is often a hindrance. The high cost is due to tooling, and the number of pieces that must be manufactured to make the product viable in the prototype phase.

Because of this, many of our customers limp along using inappropriately-applied rubber lip seals to solve rotary seal problems.

Eclipse Engineering is making a series of components from 1/8-inch shaft up to 1-inch shaft in fractional increments. The series will include the inside spacer, so we’ll only need to machine a Teflon lip to shape, assemble, and add a spring if necessary.

If the concept is successful, we can leave the design as is, and produce to your specifications (or consider refining the design to fit all your design criteria).

Typical spring loads include garter, canted coil, and elastomer (such as an O-ring ). This proven design has operated at pressures in excess of 200 PSI, and speeds in excess of 3000 RPM.

Rubber lip seals are very successful when the pressures are 10 psi and lower, often performing best at zero to just a couple of PSI. And in the right configuration, Teflon-style lip seals are capable of pressures of up to over 500 PSI and very high rotational speeds (while ensuring the speed doesn’t exceed the PV limits of the material).

Having the ability to custom manufacture a lip with a specified spring load allows the customer to control the loading on the lip and still handle eccentricities due to shaft mis-alignment. The key to making this in small volumes allows a viable, cost-effective solution.

The flexibility of varying seal materials and spring loads allows our customers to seal on a variety of shaft materials and, depending on eccentricity, what kind of spring load will be needed to continue to seal.

We’re pleased to offer this stocking solution to our customers. Our goal is to dramatically shorten lead times with attractive prototype pricing, allowing these products to be evaluated by our customers.

What Types of Seals Are In My Car?

Thu, 28 May 2020 21:00:00 GMT

You might be surprised at the places you’ll find seals like the ones we design and manufacture at Eclipse Engineering . Our seals are used in planes, trains, and yes, you guessed it — automobiles .

Eclipse specializes in manufacturing seals that can withstand extreme temperatures and environments, which is a critical capability when it comes to the countless mechanical operations we rely on everyday, especially in the inner workings of our cars.

Seals help keep everything in your car in working order, from the mechanisms under your hood to your wheels and trunk. They also prevent leakage, keeping oil, coolant, and gas in your car so you can make it safely from point A to point B.

And there are even seals around your doors and windows to keep the rain, snow, and cold (or hot) air out, helping to maintain the interior comfort of your car.

Let’s take a deeper dive into some of the parts of your car where seals make all the difference.

Engine

Without a doubt, the engine is the most important part of any car. It’s the heart of the automobile, and seals are critical in keeping it running reliably.

Seals are used throughout the engine to keep oil where it’s supposed to be and to protect the inner workings of the engine from dirt and debris, all of which are in plentiful supply on the road.

These seals are specialized to be able to withstand the extreme temperatures and conditions encountered inside of an engine, allowing them to function as expected for hundreds or even thousands of hours of driving.

Engine Control Unit

In modern vehicles, seals can be found in the engine control unit (ECU) that sits on the fender and provides information to a car’s fuel and ignition system.

The ECU is connected to sensors that tell it how the engine is performing. It uses that data to automatically drive actuators to optimize performance. Some ECUs also control the fuel injection system. Without seals to keep ECUs in clean and working order, our cars would be much less efficient.

Internal System Motors

All the internal systems motors in your car use seals. This includes the vacuum motors that open and close vents, as well as those that make your windshield wiper motors move.

The motors that roll your windows up and down also have seals installed to keep dirt and moisture out, and grease or oil in.

Doors, Hood and Trunk

In the door frame on each of your car’s doors, there are a number of seals designed to keep the elements out and to help keep the car dry and warm.

There are also seals in the lift cylinders for the hood and rear hatch or trunk to keep them sealed and to allow for ease of opening and closing. Otherwise, your trunk hatch would be very difficult to hold open, and it would slam down every time you release it.

Drive Train and Exhaust System

Your car’s drive train relies on seals in the water pump shaft seal, the head gasket, the gaskets that keep fluids in the oil pan gasket, and the final drive shaft crank seal.

All these seals see a variety of temperature changes, from extreme cold to above 300+ Fahrenheit. We even have seals in the joints of our exhaust system, which seal up as the temperature rises.

Transmission

The transmission is one of the most important parts of any car. It’s what controls the power that is delivered to the wheels so that your car actually drives at the speed you want it to.

A transmission is full of gears, and those gears need to stay well-oiled. This is where seals come in. The transmission has a myriad of seals that hold oil in, allowing the system to build pressure, which in turn helps shift the transmission through the gears.

Wheels and Shaft

A car isn’t a car without wheels, and wheels don’t turn without shafts. Whether it’s the half shafts that drive the front wheels or the drive shaft that controls the differential that turns the rear wheels, the shafts in your car use rotary and static seals to keep oil in and debris from the road out.

Brakes

A car is all about getting to where you’re going, but once you get there, you’d probably like to stop. Hence, brakes.

Today’s modern braking systems have seals in the anti-lock valves to prevent skidding. There are also seals in the brake valve that transfers the pedal motion when bringing the vehicle to a complete stop.

The brake caliper also has seals to maintain the oil within the brake, along with grease seals that keep road dirt out of the system.

Power Steering System

Without power steering, controlling a car would be very difficult. Basically, your power steering system helps you out by adding additional power, so that when you gently turn the steering wheel, the wheels on your car turn in response. Otherwise, you’d have to put a lot of elbow grease into maneuvering your vehicle.

Needless to say, power steering is a pretty important feature, and it’s a system that relies on seals. Power steering systems have a pump and cylinders, all which use seals to maintain pressure while making our steering sensitive to varying speeds.

Suspension

Both passive and active suspension systems use dynamic and static seals to help keep oil in. What’s the difference between dynamic and static seals, though?

A static seal is a seal that is between two surfaces that do not move in relation to each other, while a dynamic is one that is used between surfaces that do move in relation to each other. Both are incredibly important in the functioning of your car’s suspension.

Batteries

The batteries in your car contain seals to maintain a constant environment. This is critical in keeping the batteries internal temperature under control to ensure a long recharging life. Without seals, you’d be changing your battery a lot more than you have to now, which would be both expensive and inconvenient.

Electric Cars

Electric cars use seals to protect the motor from dirt. Rotary seals keep grease in the bearings, while keeping dirt out.

You’ll find that electric vehicles use seals in their power steering systems as well, utilizing fluid that helps make steering easier.

The Future Of Seals In Our Automobiles

Cars are becoming more and more complicated every day. We have cars that will brake for you when they sense an object in the road, that will help prevent collisions while driving, will parallel park for you, and even do all the driving for you.

These kinds of features will only become more commonplace in the future, and it won’t be long before driverless cars are a regular sight on the highways and byways of the world.

All of these innovations require devices that rely on seals to function. So regardless of the type of car or the propulsion device, seals will not only remain an integral part of keeping vehicles running, they’ll become more important than ever.

But seals aren’t just relied on in cars, planes, and big industrial equipment. They live all over the place, even in your own home.

Learn more about the everyday uses of seals >

Seals Made Overseas: Is the Savings Worth It?

Fri, 22 May 2020 21:40:00 GMT

We’ve been getting quite a few calls from customers who traditionally order their seals and bearings from oversea suppliers, such as China and India. This is likely due to the manufacturing industries in these countries continuing to be impacted by the coronavirus pandemic.

We’re getting a shot a business we’ve never had before, and we’re hoping customers review the full impact of “Made in America” and how it affects their company’s bottom line — as well as all the potential issues that come with any product purchased overseas.

Is it Really Cheaper to Order Your Parts Overseas?

There’s no question that piece part pricing from overseas can generally be lower than parts made in America. That is, until you figure in transportation, duty, lead time, and the frustration that goes with encountering any problem with the part.

If you look at the landed cost at our customers’ door, we can generally compete with a higher level of quality, delivery, and technical support compared to anything coming across any border. In the end, the overall costs of ordering parts made in America is comparable.

Taking Care of Our Customers During the Pandemic

Throughout the pandemic, Eclipse Engineering continues to be fully staffed and in production. Our Engineering department has been busy working on issues that had been on the back burner in the past.

Many of the programs we’re seeing are all about a higher level of service, with deliverables tailored to our customers’ needs. Some are all about product improvement, and others are cost driven.

We’re in business to supply product made in America on your time frame. With blanket orders, we’re happy to hold inventory to handle the fluctuations in your changing manufacturing schedule. And delivers can be handled in days, not weeks or months.

How We’re Protecting Our Employees

Like the rest of the world, many of our employees telecommute. But as a manufacturer, folks need to be in the building. Their safety is always of the highest importance, especially now.

At Eclipse, we’ve always taken care of our employees by utilizing varying shifts, operating 7 days a week, and staggering hours to ensure the safety of all those involved in the manufacturing process.

The current pandemic has made us more aware than ever that taking care of our employees means we’re able to continue to support our customers’ needs — something we’ve been succeeding at as long as we’ve been in business.

We’re asking you as our customers to consider the value of having a supplier in your own back yard. For the many customers we have overseas, our doors are open for business, and we look forward to continuing to supply your product on time and at a marketable price, with the value of technical support a phone call, email or text away.

Thanks, and stay healthy out there.

Contact us for your seal and bearing needs >

History Unlocked: A Look At The O-Ring

Fri, 01 May 2020 15:00:00 GMT

The mechanical O-ring is a very simple item, hidden from view in most applications and unappreciated by the millions who benefit from its use in the technologies that make much of modern life possible.

Since its humble beginnings in Sweden at the end of the 19th century, the O-ring has grown to become a ubiquitous and crucial mechanical seal component in a huge range of technology. O-rings are used in industrial machinery , farming equipment, cars, airplanes — even spacecraft.

Needless to say, with this unassuming little miracle, many of mankind’s achievements of the last century would have been impossible.

What Is An O-Ring?

A mechanical O-ring is made of elastic polymer in the shape of a letter ‘O’. It provides a mechanical seal to contain liquids or gases. It typically sits in a groove, compressed between a piston and a cylinder.

It’s also used to seal static, or non-moving, circular joints between metal components.

The fundamental feature of modern O-rings is the material they’re made out of — rubber. That’s where our story begins.

How Rubber Became a Pillar of Civilization

Rubber as it’s found in nature was used by the Mayans and Aztecs for bouncy ball games, and was first used by Europeans as a pencil eraser around 1770. It then graduated to clothing and footwear.

However, a consistent problem encountered with the rubber of this time was that it was brittle and, when left in the sun, would gum up due to the heat.

A revolution came by way of accident in the year of 1840, when Charles Goodyear (recognize that last name?) stumbled upon vulcanization through use of a sulphur additive.

Vulcanization is a chemical process which alters the characteristics of rubber, vastly improving its capability to withstand heat and pressure. It’s less prone to swell, resists abrasion, has a higher tensile strength, and is more elastic across a wide range of temperatures.

This discovery greatly expanded rubber use during the Industrial Revolution. Suddenly, it was showing up everywhere, in everyday items such as tires, hoses, shoe soles, and fan belts.

Dependence on natural rubber ballooned over the next few decades. By World War II, the United States was consuming about half of the world’s supply of natural rubber.

A fighter plane at this time was built with 1,000 pounds of rubber. A battleship? 150,000 pounds.

There was one major problem, though — natural rubber was subject to supply problems. Plus, it wasn’t cheap.

Enter synthetic rubber. It had actually been invented years earlier, in 1909. By polymerizing methyl isoprene, a German team of researchers led by Fritz Hofmann was able to devise synthetic rubber.

But it wasn’t until the middle of the century that the overwhelming demand for rubber grew so much that eyes turned toward the synthetic option.

President Roosevelt set out to solve the problem by establishing a partnership with the country’s biggest rubber companies to mass-produce synthetic rubber Styrene, at twice the output of the world’s total natural rubber production before the war.

After the war, this development allowed rubber to become ever more pervasive in consumer and industrial products.

From the 1950s to the 70’s, rapid advances in synthetic polymers led to better and better variations on rubber, ultimately creating today’s high-performance elastomers.

Who Invented O-Rings?

The advances of O-rings run parallel to the improvements made in rubber technologies over the course of the 20th century.

The very first patent for the rubber O-ring was filed back in 1896 in Sweden, by J. O. Lundberg. He is credited as the original inventor, but unfortunately not much is known about him.

Meanwhile a machinist, Niels Christensen, immigrated to the US from Denmark in 1891, and filed his own U.S. patent in 1937 at the age of 72, about 40 years after Lundberg.

Soon after that, he also patented an air brake system for trams, but his intellectual property was passed from company to company, including Westinghouse, despite his legal efforts to maintain his rights. Eventually though, Christensen would receive compensation of $75,000 for his work on O-rings, with further payment to his heirs much later.

How The O-Ring Became Ubiquitous

The inauspicious birth of the O-ring stands in stark contrast to the star turn it took in World War II. It was at this time that the United States government commandeered the rubber O-ring patent as a piece of critical mechanical seal technology and gave manufacturing rights to various organizations.

This was right around the same time that FDR prioritized a nationwide pivot to synthetic rubbers. It turns out that O-rings and high-performing synthetic rubbers were a match made in heaven.

With the more elastic and durable properties of synthetic rubber aligned with the simple concept of a sealing ring, it was now possible to rely on O-rings to help automobiles stay on the road, planes in the air, and much more.

The O-Ring’s Infamous Role in The Challenger Explosion

After the tragic explosion of the Challenger space shuttle in 1986, physicist Richard Feynman famously demonstrated on television that the root cause was an O-ring failure, due to low temperature.

The extreme cold had caused the rubber o-ring to became rigid , losing pliability, and failed to seal a joint on a rocket booster, causing high temperature gases to blow-out. This led to a total structural failure and disintegration of the shuttle.

After the disaster, NASA scientists re-designed the rocket booster with an onboard heater, keeping the O-rings up to at least 10°C –– which fixed the problem for good.

A Transformation of Industry Standards

After the tragic destruction of the Challenger, a lot more was learned about O-ring material properties and limitations. And many more people realized just how much was being asked of such a simple invention.

The accident led to stricter documentation and regulation around O-rings. They were labeled with batch, date, and manufacturer information, allowing precise tracking and control of distribution –– much like products in the medical industry .

Aerospace and military sectors, who especially needed to ensure their o-rings never failed, went to even greater lengths. They used individually packaged o-rings with detailed material information, so they could easily be recalled or tested in case of failure.

These transformations increased the reliability of o-rings greatly, which is why we’re now able to use them widely in extremely sensitive applications.

Achieving Critical Quality In O-Rings

O-ring performance can mean the difference between success and crisis, as the Challenge episode illustrated. For this reason, they are commonly subjected to very stringent quality control procedures, with multiple rounds of quality and assurance and stress testing before release to users.

Eclipse Engineering supplies and supports O-rings from the best sources in the world, using resilient materials and rigorous manufacturing processes to ensure consistent and reliable operation — especially for high-stake applications in aerospace , pharmaceutical , and semiconductor industries , along with the food and beverage , energy , and automotive sectors.

Want to know more about our O-ring standards and supply sources? Contact us today »

The Role of Seals in the Quest for a Coronavirus Cure

Thu, 23 Apr 2020 19:06:00 GMT

The coronavirus has prompted all of us to do everything we can to protect ourselves from catching and spreading the virus. We are all taking important safety measures to maintain a clean and uncontaminated home environment, and limiting our exposure to a potentially hazardous outdoor environment.

At Eclipse, we’ve been interested in examining the role that seals play throughout the pandemic. The very role of seals is to keep a certain environment in, and certain environment out.

We recently wrote about boundary seals in aircraft and how seals allow the aircraft to be pressurized. In the research lab, a different style of boundary seal is required to keep the outside environment out.

Labs all over the world are working toward preventing the spread of coronavirus. Scientists are working with test equipment to find a cure and a vaccine to prevent not just the spread of this virus, but other viruses which we’ve not yet seen.

When we design seals, we must consider keeping something as small as a single cell from entering a test chamber. Last week, we received a call from a customer building a prototype ventilator to be built in volume to help support patients suffering from coronavirus.

The client requested that our engineering and manufacturing team turn an 8-inch (203mm) seal around from concept, design, and finally produced and shipped in less than 4 hours — and we made it happen.

Keep reading to explore the important role that seals play in research equipment as scientists seek to find the cure for coronavirus and beyond.

Seals in Test Equipment

Oftentimes the lab equipment has its own environment, such as an inert gas or some other purging environment to keep the outside world from contaminating the specimen being tested. These types of seals can be static or dynamic.

Static seals are typically used to provide a barrier to the outside world and maintain an environment within a chamber. Dynamic seals, on the other hand, allow for a change in environment by changing the pressure, or allowing the flow of fluids into the environment.

This could include pressurizing the sealed-off environment to allow a further change in how the specimen reacts. The chamber itself may include seals to capture heat and cold for processing the specimen.

When we design for test equipment, we must consider not just the first test run in a chamber but ultimately many tests, so seals must have the capacity to be cleaned or sanitized.

An autoclave is often used to thoroughly clean a test chamber. The seals in the chamber must be able to withstand heat, steam and gamma radiation to insure the next test sample is not contaminated by the previous sample.

Designing and Manufacturing Lab Seals

We take into consideration all of the factors explored above when designing our seals for lab equipment. The number of seals in any order and how they’re going to be installed is considered for the purpose of manufacturability.

Lab-type equipment also often requires seals with extremely small cross section and diameter to ensure that loss of volume displacement is extremely small during testing.

Manufacturing seals to 1mm ID allows for volume displacement during the injection or titration to be extremely small and accountable. We normally use materials like Teflon or PTFE and load the seal with springs, like a Canted Coil spring , which affords us the ability to make small seals in very small envelopes.

Seals like these are often found in test equipment for High Pressure Liquid Chromatography , or HPLC. These seals are often used with pistons made of ceramic. That means low friction is extremely important, as pressures may reach over 300 bar as the fluid is pushed through a filter bed.

Again, contamination of the sample is of utmost importance, so static boundary seals around the test chamber are critical to ensure the validity of test results.

Best Material for Lab Seals

These boundary seals are often made of rubber. However, when we consider the cleaning fluids, autoclave, or gamma radiation, this often makes standard rubber boundary seals unusable.

Spring energized seals can be a promising answer. Spring energized seals have extremely low porosity, and allow for metal springs which will maintain a constant force against the outside environment. Plus, these seals have no problem tolerating the operating environment along with the rigors of cleaning.

These seals are often custom-designed to support the optimal design of the test equipment. Seals can be manufactured to easily be extracted and replaced without damage to the test equipment or other seals in proximity.

Eclipse Engineering custom-designs seals for virtually every application under, on, and off the planet. But today, we’re dedicated to helping scientists all over the world find a cure for coronavirus.

Eclipse Engineering is engaged in keeping those segments of our economy such as food, pharmaceuticals, and chemical processing in place for our everyday lives to continue safely. When called to action, we’re here to support your needs.

Learn more about how our seals have been used to support the medical equipment industry »

How HEPA Filters and Boundary Seals Help Protect Us During Pandemics

Wed, 01 Apr 2020 21:44:00 GMT

Boundary seals that help keep a certain environment sealed in while keeping the world out are everywhere.

If you look around your home, you may be surprised to see there are seals surrounding every door — and not just at the bottom. Your oven, microwave, and of course refrigerator door all have seals around them.

All these seals are different, yet they perform the same function. Your microwave is especially interesting, as its primary purpose is to keep microwaves from escaping the chamber that’s cooking your food. Your refrigerator seal has a magnet built into it, which keeps the door sealed shut.

Boundary seals are also found in many cell phones and electronic devices, keeping them water-resistant or water-proof (depending on the manufacturer). And in the industrial world , we have seals to create explosion-proof boxes in hazardous environments. The simple O-ring is found at the end of every cylinder cap to keep fluids in and the environment out.

We all go through great expenses to seal our houses from the outside with sturdy doors, only to find that we need fresh air here and there. Our windows have a series of seals around them keep the heat or the cold outside, but can be opened to allow fresh air when we want it.

In the same way that boundary seals work, the pandemic has many of us thinking about how to keep hazardous germs from entering into our homes. And if we have to fly, we may wonder how fresh the air is in the cabin, and if viruses have an easier time spreading inside of an airplane.

Boundary Seals in Aviation

Let’s begin with general aviation aircraft with pressurized cabins. The door’s seal is in the form of a bladder, which you pump up with the same type of bulb often found on a blood pressure cup.

Doors are especially difficult to seal, as they’re required to open and close. A rubber seal that would compress and seal the door completely would make the door too difficult to open and close.

After the door is closed, the pilot pumps up the bladder to seal the door. As the engines are wound up, the flight deck begins the process of pressurizing the aircraft. A pressure system from the engine maintains the pressure within the cabin around 8000 feet, allowing the pilot to breathe without the use of supplemental oxygen.

While these seals are not dynamic in the true sense of the word, they are constantly changing based on the altitude of the aircraft.

Most of the pressurization seals on our modern jets are static. But every door, including the luggage compartment, has seals that must be pressurized in order for the aircraft to maintain a safe level of oxygen in the cabin.

Do Jet Planes Blow Clean Air?

Many travelers worry about getting sick on airplanes. With tight quarters and no ability to open a window and get some air, travelers may wonder whether the air from the vents above them is blowing fresh air — or if it’s circulating stale air and germs.

A few months ago, I performed a non-scientific study on a flight by asking the passengers next to me what they thought of the circulated air in modern aircraft today. I was not surprised to find a wide range of answers, varying from someone envisioning a squirrel blower forcing air around the cabin, with others believing 100% of the air comes from the outside.

HEPA Filters on Airplanes

The truth lies somewhere in-between. Turns out, 50% of the air blowing through jet cabins is actually coming from the outside.

That’s one of the reasons why the air that blows through the vents is so cold — the 50% of air that comes from outside is around -30F, which is why stewardesses need to turn the heat on to keep us comfortable.

The rest of the air is recirculated air through a HEPA filter system, or “High Efficiency Particulate Air.”

This is the same air found in surgical operating theaters or clean rooms, with an efficiency that oftentimes exceeds 99% pure. In our modern-day aircraft, this filter helps stop the spread of whatever just came out of that guy’s mouth 5 rows up, cleans cigarette smoke, and even works to stop the spread of infectious viruses through the cabin.

If you’re traveling on one of the silver birds, your best option for the cleanest air is to turn that overhead jet on high and let it blow around your face. This funnel of air forces air that may be lingering around your nose and mouth aside, providing a fresh stream of clean cool air.

I spoke to the pilot or driver of an A320, who has seen the process of cleaning the HEPA Filters. He claimed it was about as nasty as cleaning…well…you get the point.

Another pilot friend of mine suggested that if you have to travel during the coronavirus outbreak, you should turn the air on and allow the HEPA filters the opportunity to blow clean, fresh air over your nasal cavities, promoting a safer ride and reducing the probability of infection.

So, bundle up, turn on the jets, and sit back and enjoy the ride. The door seals will keep you breathing, and the HEPA filters could keep you safe.

Learn more about the ever-growing performance demands on seals in modern-day aircraft »

The Advantages and Disadvantages of the Channel Seal

Tue, 10 Mar 2020 21:29:00 GMT

The Channel Seal (or Cap Seal, as it’s often referred to), was one of the earliest forms of Polymer or Teflon sealing in the seal industry.

The product is easily applied. It didn’t replace the O-ring , but instead offered improved life while reducing drag.

In doing so, hydraulic and pneumatic systems operated cooler and quieter, while improving overall performance of the product.

Evolution of the Channel Seal

Before the Channel Seal, the Backup ring was established. The first Backup rings started out as leather, as this material was readily available and could be easily formed into any shape with simple dies to stamp the Backup ring out.

Back up rings provided support for the O-ring, allowing the O-ring to operate at higher pressures, while closing off the Extrusion or “E” gap. This stopped the O-ring from being nibbled in the extrusion gap, there-for extending the life of the O-ring.

Teflon Backup rings were a big improvement, as they would better fill the gap and would stay put (as opposed to leather, which tended to shift in the groove). With the use of two Backup rings, an O-ring was well supported from pressure in both directions.

It was a simple matter to connect the two Backup rings with a thin membrane of Teflon, which removed the O-ring from the sealing surface. This change reduced drag and improved performance, while still maintaining an excellent mechanism for extrusion resistance.

This design was relatively simple to machine out of Teflon, but installation was a challenge, as the Backup rings were full depth. This caused the seal to become distorted during the install process. Today, we almost never see this type of design.

With CNC machining, the ability to nestle, and an O-ring design in a complex Teflon shape gave rise to what is referred to today as the Channel Seal, or Cap Seal .

This style seal offers an abundant of advantages over standard back-up rings and the early version of the Channel Seal, which was simply a Backup ring with the membrane of Teflon in-between.

The Advantages of the Channel Seal

The Channel Seal incorporates Backup rings that protect the O-ring against extrusion. The seal’s non-rubber contact patch reduces drag, thereby reducing friction. The overall system heat is also reduced due to this much lower friction.

The seal installs into standard 0,1, and 2 Backup ring grooves. This affords the user extrusion a tremendous advantage when space is at a premium, even in a zero Backup ring groove.

Fillers can be added to the Teflon to improve wear and extrusion resistance. And, above all, installation is greatly improved over a standard duel back up rings as this is combined in the seal package.

For extremely small applications, grooves may need to be split. But there are tools available to help kidney the seal and a resizing tool may be used to bring the ring back to its original shape.

Typically, the seals may be installed with no tooling. Their thinness allows them to be smoothed back into shape.

In the event the thin web cross section wears out, the seal reverts to an O-ring, with two Backup rings to help continue to support it.

The Channel Seal has been heavily employed in the aerospace industry . It’s also found a home in control systems where friction and drag in pneumatic systems are extremely important.

Cons of the Channel Seal

Like any Teflon seal, leakage is not as good as a simple O-ring. But due to the extremely thin membrane, the Channel Seal has leakage just above the leakage of an O-Ring.

Surface finish also needs to be a bit better than an O-Ring, but in either case, finish improves leakage and drag, while improving the wear live. Finishes of 8-16 Ra are generally very acceptable.

The Benefits of the Channel Seal

The Channel Seal can be designed to fit nearly any O-Ring groove, as its CNC-machined to fit your specific hardware. With a slightly deeper groove, the web thickness can be increased to improve wear life with little change in leakage.

Overall, given the Channel Seal’s extreme flexibility and ease of installation, it can easily fit most of your O-Ring sealing needs with no change in hardware.

Eclipse Engineering has a full standard line of Channel Seals, and can custom manufacture to meet your very specific needs, including sealing on an angle or face style seal.

Discover the advantages and disadvantages of the PTFE O-ring »

Best Sealing Materials for Epoxy Resin

Wed, 19 Feb 2020 02:15:00 GMT

Sealing viscous fluids like epoxy resins requires a seal that contains enough force to ensure a good scraping action, while not overloading the shaft you’re trying to seal. This is often accomplished by selecting the best spring that will continue to be reactive, regardless of the fluid.

This means selecting a spring material that can successfully handle the following challenges:

Temperature is sometimes also a factor in sealing, which means some seal materials aren’t suitable for these tasks. And of course, the chemistry of the fluids can’t interact with the spring or the seal.

The seal must be rigid enough to stand up to all the above conditions, and at the same time be flexible enough to be installed, and reactive to some side-loadings.

Best Seal Material for Sealing Epoxy Resins

We generally turn to two different seal materials: PTFE or Teflon , and UHMW or Ultra High Molecular Weight Polyethylene.

There are many differences between these two materials. The UHMW tends to be very stiff, and thereby does an excellent job of scraping. However, it’s often limited by temperature, and some fluids can react with it, although most epoxy resins don’t interact with UHMW.

On the other hand, Teflon is far more compliant than UHMW, has a broader temperature range, and chemical resistance is almost never an issue (especially with epoxy resins).

So how do you choose which seal material will work best for your needs? The answer boils down to a few factors: Temperature, which relates to speed (especially in rotary applications), and how well the seal will scrape off the shaft.

Speed in Epoxy Seals

Teflon performs better at high speed. But UHMW holds an edge better, which means it ultimately does a better job at scraping.

Springs are generally not an issue, as few chemicals in epoxy resins will affect stainless steels. But the type of spring you use is very important. You can expect that the fluid will completely cover the spring, so the spring force needs to stay unaffected by metallic springs.

The cantilever spring generally offers the best solution, as it allows the fluid in and out of the spring cavity, where other springs tend to hold the fluid, thereby affecting the overall spring force.

The cantilever cavity can be filled with silicone to close off the cavity. This keeps the viscous fluid from impacting the performance of the spring in the application.

Beyond a cantilever spring, other types of energizers tend to not do as good a job in overall performance. This includes O-rings , which are often affected by the fluid, or round springs like Helical , which tend to trap the fluid in the spring cavity.

Fillers for Epoxy Resin Seals

There are fillers that we apply to UHMW to enhance the performance and extend the life. They generally cost a bit more to produce, as they wear tools and could impact the shaft finish and wear life.

Teflon is always an excellent choice with the correct fillers selected. But again, Teflon doesn’t hold an edge for scraping.

While Teflon and UHMW are great choices for sealing and spring materials, these aren’t interchangeable due to the nature of the polymers and the desired result.

If we seal after the two-part epoxy is mixed (prior to leaving the head), we need to be prepared to clean or flush the seal quickly (prior to the compound hardening in place). Our selected seal material must be able to stand up to some of the harshest cleaning fluids and resist chemical break down during the cleaning process.

Rotary Applications for Epoxy Seals

Rotary applications are both easier and more difficult. We often see rotary during a mixing process, and Teflon will handle the increased shaft temperature much better than UHMW. And without the reciprocating action, the rotary seal only needs to provide enough downward force to not allow the fluids to push up the lip during operation.

The reciprocating action tends to want to draw or drag fluid past the seal. That’s why the edge and force on UHMW works so well. Whereas in rotary, no fluid is being drug under the lip, so penetration of the boundary is much more difficult.
Eclipse has designed seals at less than .062 inch (1.5mm) for many reciprocating applications with various types of seal materials to accommodate size, installation and operation of the Epoxy Pump mechanism.

We have also designed a series of rotary seals, all of which can be CIP or clean-in-place sealing elements.

Learn more about the designs and materials of Clean-in-Place seals »

The Revolution from Plastic to Teflon Seals

Thu, 30 Jan 2020 22:56:00 GMT

The term “plastics” is generic way of describing a synthetic material made from a wide range of organic polymers. Organic polymers describes a man-made substance that is formulated using polymer chains to create what we commonly refer to as…(you guessed it), plastics.

Before plastic, leather had been used to create Backup ring devices behind O-rings . Leather allows fluids to be retained, providing lubrication for the O-ring when the system was running dry.

The problem with leather was that it could become dry and shrink away from the sealing service, exposing the elastomer to same pressure it was intended to protect against.

With the advent of polymers, a piece of plastic could be cut or formed into the exact shape to allow for zero extrusion gap, and for continued protection for the O-ring.

Some polymers were very brittle. Since they needed to be deformed to allow for installation into solid glands, the cut of the plastic could nibble at the O-ring, causing premature failure of the element it was supposed to be protecting.

The Revolution of PTFE

When PTFE moved out of the lab and into industrial use, it quickly found itself adjacent to the O-ring. PTFE offers extrusion resistance and, at the same time, doesn’t erode or nibble at the O-ring due to the “softness” of the polymer.(Hardness between 55 and 65 Shore D)

Given the composition of PTFE, or Teflon , it was that PTFE could be utilized as a sealing element to protect Backup Rings and conform to the shaft. The bonus was it was generally easy on shafts (depending on the filler added to the PTFE).

There are some negative aspects to Teflon that needed to be overcome by early engineers. First, it has a fairly high rate of Thermal expansion which, by its own nature, could often times lose contact with the sealing surface. This meant some kind of loading was necessary to ensure contact.

PTFE is as tough as other polymers, so the fact that it could seal on a shaft made it vulnerable during installation for tears or nicks on sealing surface.

Second, if it were stretched during installation, the material had to be sized back to its original shape due to its poor elastic properties.

The Benefits of Teflon as a Sealing Element

So what makes Teflon such a powerful sealing element?

Teflon’s low coefficient of friction also makes it an excellent wear ring. Teflon has a compressive loading of around 1000PSI, but because it’s not a rigid body, the load can be spread out. This spreading out of the load eliminates point loading that’s often found in a new bronze bushing.

As bronze bushing begins to wear on one side, it wears and creates an egg-shaped profile, spreading out the load by wearing into this “egg” like shape. If the load moves around from a shaft, this same process of spreading the load out begins over again. Eventually, enough of the bronze is worn away, and the bearing must be replaced.

In the case of Teflon, this spreading of the load occurs when the bearing is new, so the load is shared over a broad area to improve load carrying capability with a smaller bearing. Fillers are added to improve wear, but the load-carrying capability can’t be improved, as the load is always carried by the base polymer.

Coefficient of Thermal Expansion for Teflon

At 77 °F, the coefficient of thermal expansion for Teflon is 7.5×10^(-5) in/in/°F. This means that when we design a bearing strip, it’s designed at room temperature with a gap.

This gap is designed with the knowledge of the thermal rate of expansion, and how much of a temperature change we’re expecting. By designing in the proper gap, we never completely close the bearing strip. And at lower temperatures, the gap is small enough that we still get excellent bearing coverage.

With the coefficient of friction being so low, .04ƒ, Teflon makes a very slick surface to run rods or pistons on. By using Teflon in our sealing and bearing elements, we keep friction in the system to a minimum without adding heat into the operating system.

PV, or pressure times velocity, gives us an indicator as to how well the material will survive in the operating conditions. We won’t go into the calculation, but with the understand that staying within the PV limits gives the design engineer some boundaries to work around.

This becomes especially important in Rotary seal applications, where a small amount of pressure and high velocity can easily cause the lip seal to exceed the mechanical strength of the polymer.

The Engineers at Eclipse Engineering have been designing canned rotary lip seals for over 20 years, and are well versed in the application of these constraints in your sealing application.

Canned rotary seals can take on many forms, from simply injection molded rubber into a can to a spring energized seal with a built-in scraper in a can design. These are some of the areas where polymers like PTFE or Teflon do an excellent job of handling high PV with long life.

Rotary shaft hardness and roughness are important considerations when selecting the right PTFE lip seal. Read our guide to avoiding seal failure by getting optimum performance and longevity for your seals and shafts »

Seals for all Seasons: Perfluoroelastomers

Mon, 16 Dec 2019 21:14:00 GMT

In the sealing industry, we follow a basic design scheme to help us determine what the best seal for the application will be. We’ve learned that the first place to start is the basic O-ring .

The O-ring’s low cost and ease of installation makes it our number one choice. And while we have a variety of materials and cross sections, the basic O-ring often delivers the best bang for your buck.

But what happens when the required environment is calling for an O-ring, but the fluid or temperature exceeds what the standard O-Ring can provide?

Perfluoroelastomers may solve these difficult sealing needs where other solutions can’t. Perfluoro’s give the seal-ability of an O-ring, combined with the temperature and fluid resistance of Teflon .

A few of the industries that have taken advantage of these rare characteristics are the semiconductor , oil , chemical, and pharmaceutical markets . These industries require seals to work in extreme chemical and temperature environments, and not allow the introduction of the seal materials to enter the fluid stream.

There are several different ways to accomplish this, but the first thing we must consider the operating characteristics.

When to Use Perfluoroelastomers

For static seals where no relative motion exists, the use of perfluoroelastomers, or FFKM rubber, is a first consideration.

Perfluoroelastomer parts have excellent chemical and thermal stability, and have been specially formulated and processed to meet the unique requirements of these varying industries. Depending on the application, standard O-ring grooves will accept these molded O-rings and custom seals using a series of specialty compounded elastomers.

For example, in the semiconductor industry, ultrapure compounds have been developed with the express purpose of not contaminating the fluid stream.

For dynamic seal applications where wear and friction are a concern, in these same operating conditions, Eclipse designs and manufactures spring and rubber energized seals made from materials such as Polytetrafluoroethylene PTFE, (Teflon®) or Ultra High Molecular Weight Polyethylene.

In combination, we may use a Perfluoroelastomer on the static side of the seal, or as an energizer where a metal spring could contaminate the fluid stream.

These seals are typically machined cross sections and energized by metallic springs or rubber elastomers. PTFE is essentially inert to almost any chemical, and a metal spring can be selected from the accepted metals that are used in other areas of the equipment, typically a 300-series spring steel.

If the seal is rubber energized, the use of a Perfluoroelastomer provides excellent chemical and temperature compatibility while allowing for the performance of Teflon or UHMW for the dynamic member.

The use of these polymers allows for dynamic motion to occur without abrading the mating surface. These polymers can resist contamination in the fluid stream, while keeping friction to a minimum and operating in varying temperatures to satisfy the application.

Dynamic seals can operate in reciprocating, oscillatory and rotary motion. Due to their relative coefficient of friction compared to elastomeric seals, these polymers can dramatically reduce the amount of heat induced by the dynamic motion into the system.

These materials are not limited to round shapes. They can be machined into virtually any profile to accommodate the application.

Temperature Limits of Perfluoroelastomers

When pressures exceed the mechanical strength of these standard polymers, Eclipse Engineering can build backup ring combinations to handle pressures exceeding 100K PSI.

When pressures go negative or vacuum, we’re capable of building sealing systems that are capable of sealing to extreme vacuum, and continue to function as dynamic seals. This is accomplished with our super finish process for polymers, in combination with the application hardware and finishing of the mating surface for the dynamic application.

For boundary seals in electronic enclosures, we can design seals or protection devices to keep the outside environment separated from the environment within the electronic device.

We have designed polymer enclosure seals that operate in severe glove box environments. We also build electronic enclosures to insure product remains within the enclosure.

When designing with the harshest of chemicals and operating at temperatures that can swing from -400F to in excess of 500F, the use of a polymers such as PTFE and elastomeric materials such as FFKM provide for long-term solutions that will keep your production equipment up and running longer, and your PM cycles to a minimum. This helps reduces overall downtime, improve run time, and ultimately makes your operation more profitable.

Eclipse Engineering has been supplying Perfluoroelastomers like Kalrez in the market place for 20 years, and has the experience to solve your sealing needs. Contact us today with any of your specialty sealing needs »

Spring Types and Materials in Sealing Systems

Fri, 08 Nov 2019 16:15:00 GMT

Springs are an integral part of all sealing systems. A simple air cylinder has O-rings to seal in the air, and the O-ring exhibits spring-like qualities to ensure a good seal over a broad temperature range.

Metal Springs

Metal springs, such as the Cantilever and Canted Coil spring , are used to energize polymers such as Teflon and UHMW to allow sealing in a wide range of temperatures. Selecting the correct spring material is critical to the life of the seal.

Metal energized seals are often subjected to a wide variety of fluids and temperature ranges, which then requires the correct material choice for the life of the seal in the application.

One of the earliest metal springs was the flat band or marcel expander, often made from common materials like 300 series Stainless Steel or heat treated 17-7 Stainless Steel.

These materials are often chosen for their tensile strength. But due to the cost to manufacture and the high volumes of spring required, these two expanders were often relegated to industrial or aerospace hydraulic systems.

If system fluids were not compatible with Stainless Steel, customers generally went to a different sealing system to avoid the high cost of short runs in these styles of energizers.

O-Rings cover a wide range of temperatures, and fluids, but generally not both. If there are multiple fluids involved, O-Rings often fail to provide compatibility over a range of fluids.

The use of Cantilever, Canted Coil or Helical coiled spring allowed for long runs and lower costs. The most common spring material is Stainless Steel, but these styles of spring lend themselves to materials that have a wide range of chemical and temperature range while maintaining tensile strength.

Alternative Spring Materials

Some of the more common alternative materials are Hastelloy and Elgiloy. While 17-7 is available, it’s seldom used because Elgiloy (while more expensive per pound) is often run at a higher volume, bringing the overall cost down making 17-7 less attractive due to cost.

Another style metal spring for polymers is the Garter spring. Garter springs are normally run on a per job basis, but because it’s made from wire, it can easily be wound from any material like Elgiloy or Stainless.

Garter springs are often used in rubber style lip seals, but we often find them coupled with polymer-style seals.

Mechanical Seals

Mechanical face seals typically marry a material with the fluids the seal will be running in. Mechanical seals have the overall body and internal springs made from specific materials capable of handling variations in temperature and fluids.

PEEK in Seals

Polymers are thought of as seal materials, but PEEK has been used as a spring in polymer-style seals. PEEK can be wound into helical style springs, and also formed into cantilever springs. As a Helical style, it can be wound into a diameter to energize Teflon or rubber lip seals.

If you consider radiation service, a PEEK spring makes an excellent choice keeping metals out of the seal.

How to Choose the Right Spring Material

While there are a variety of metals, often economics determine the practicality of specialty metals.

A consideration is reviewing the hardware used in the application as to what spring material is acceptable in an application. We often review what the customer is using in the rest of the service for determining a spring material.

Temperature is often a key factor in determining materials for spring. Elgiloy tends to do an excellent job in maintaining tensile strength at elevated temperatures.

Spring Manufacturing at Eclipse Engineering

Eclipse Engineering is a manufacturer of a variety of Spring Energized Seals . We have the capability to design and build a seal with the exact seal and spring combination that meets your application needs, not just the one we “have on the shelf.”

We design in Canted Coil, Cantilever, Helical, and Garter spring. And we stock Stainless, Hastelloy, Elgiloy and of course a wide range of O-rings as energizers for our custom blended polymers.

Eclipse Engineering designs, manufactures, and distributes a wide range of products designed for applications found under, on and off the planet. We recognize the need for immediate response to keep pace with your manufacturing schedule.

How Seals in Modern Farm Equipment Increase Uptime

Tue, 15 Oct 2019 14:37:00 GMT

Before mechanization on the farm, different tools and implements had fairly simple designs. Seals were only found in the sucker pump tied to the Aermotor windmill, where there was a leather seal in the transmission and the pump had leather packing.

The History of Farming Technology & Seals

The farm tractor evolved to include rubber lip seals and some O-rings to help keep fluids in and the dust out. While sealing was important in the early 1900s, it didn’t become highly significant until hydraulics were added to farm implements, creating the ability to move product from the fields and into silos and finally to market.

The family farm stayed small for many reasons. The first was the expense of equipment that could improve productivity. Unknown crop yield and market uncertainty often slowed the growth, so farmers often just grew enough to satisfy the needs of their family and to cover expenses, with maybe a little left over.

When farming became more commercialized, farming equipment no doubt saw a huge leap in design technology, with new investments to advance the science of farming.

The Evolution of Farming Technology

Today’s modern farming equipment utilizes high-pressure hydraulics with piston pumps and motors to improve efficiency. You can find hydrostatic drive motors for running equipment, hydraulic cylinders for virtually every operation to enable the large equipment to work the fields.

Modern crop growing has also seen great improvements to allow for higher yields in the field. Rather than sending a tractor or aircraft to the field to spray crops for insects or weed control, modern farms utilize drones to accurately place just the exact amount of product down for the conditions under the craft.

Seals in Modern Farm Equipment: Increasing Uptime

Technological advancements have created an explosion of technical seal products in today’s modern farming equipment.

A major driver has been improving the uptime of equipment to ensure that the labor to operate the equipment is kept to a minimum. These efficient industrial farms will move equipment between farms to increase uptime and utilization, resulting in a quicker pay back.

This increase in productivity can’t happen unless the seals in the equipment is specified for long life, with any parts replacement happening at night when the equipment isn’t in use.

Today’s farm equipment has reached the level of modern construction and mining equipment, where uptime is the highest priority.

Shaft Seals in Gang Mowers

A few examples of where sealing technology have been shown to save on downtime are gang mowers. These pieces of equipment are generally run with hydraulic motors.

The shaft seals in gang mowers must withstand return pressures up to 150 psi, without damaging the seal. This is accomplished with specially-blended Teflon lips sandwiched in a can for anti-rotation.

Hydraulic cylinders using a combination of buffer rings and Urethane u-cups to keep oil in, and piston seals from filled Teflon to help improve life and keep heat down to a minimum during operation.

The bronze bushing found everywhere in the old farming equipment have been replaced with composite bushings. Composite bushings retain lubrication and run well in wet conditions, such as cotton or rice farming, as well as in dry, heavy dust environments. Composites minimally wear shafts and can carry much greater loads than their bronze counterparts.

Seals Around the Tractor Cab

Environmental seals around the tractor cab make the cab more of an office than a tractor. Auto pilots and auto throttles plant at exactly the right rate with no waste, while keeping the operator in an environmentally clean “cab like” compartment, which helps increases the productivity of the operator.

Rubber-energized and spring-energized dynamic seals allow this equipment to operate at much cooler temperatures, which in turn increases their uptime in the environment. With cooler running hydraulics, the equipment doesn’t need the energy to help cool the hydraulics.

Rod Wipers & Scrapers

One added element that extends the life is the rod wiper or scraper. The field (by virtue of the application) is extremely dusty, and having active wipers allows for these high-pressure systems to operate in clean fluids, which improves life and time between replacements.

Wipers can be designed to be replaced with or without disassembly of the cylinder, allowing this element to be replaced without taking the unit out of service for an extended amount of time.

Industrial farm tractors are being asked to accommodate a wide variety of attachments. While Power Take Offs “PTOs” have been around for decades, these power systems are now being tasked with accommodate a wider variety of attachments, which places greater loads on the mechanical outputs of these devices. Not to mention the accommodation of transmissions which run at very low and very high speed.

Higher shaft speeds are accomplished with the use of Teflon lip seals to retain lubrication and handle various transmission fluid types. The Teflon lip seal, while found in many rotary applications, provides low-friction and dirt exclusion, while keeping fluids in and dirt out.

Eclipse Engineering has a range of standard products and can custom design for your unique applications that require seals not yet invented to fit your specific needs. Learn more about Eclipse’s capabilities in the energy industry »

The Many Uses of Polytetrafluoroethylene Seals

Tue, 24 Sep 2019 21:14:00 GMT

Better known as Teflon in the industry, Polytetrafluoroethylene is widely used in practically every industry on and off the planet (and even beneath its surface!)

Medical Uses

This material’s primary claim to fame is its resistance to most chemicals. It inherently has an extremely low coefficient of friction, it’s easily machined from rods, tubes or compression molded shapes.

It’s one of the few polymers that are approved for medical implants due to its inertness to bodily fluids — the immune system principally ignores its presence in the body.

Moving away from the body, you’ll find PTFE or Teflon products in medical devices such as heart lung machines, rotary tools for cutting, and sealing devices for maintaining fluid streams for irrigation and pumping. Tiny fragments that may come loose during usage are not harmful to the body, and simply pass through the system.

Pharmaceutical Uses

In the pharmaceutical industry , Teflon is used in the processing of drugs for equipment used to manufacture such as mixers, presses, bushings. Teflon is found in a variety of applications, as any debris from the seal will pass through the body without consequence.
When considering press machinery (which are often water driven to ensure any leakage will not spoil the product), Teflon seals are often used to help reduce friction — especially in repetitive presses where a build-up of heat would be detrimental to the seal and the product.

Food & Beverage Uses

Mixers are another area to insure keeping grease and other contaminants from the motor to not descend into the product from the mixer shaft.

Another area is pressure vessels where two shells are clamped together to ensure product remains sealed inside. Failure of these seals usually results in loss of product.

Non-metal bearings that don’t requiring grease in rotary motion are an excellent place for Teflon style bushings. These bushings provide long life with very low friction while not contaminating the product. Shaft wear from the bushing may be eliminated with the use of Teflon.

Types of Polytetrafluoroethylene Seals

Seals in the medical field can be as simple as a static O-Ring , or a mechanical face seal which is costly and requires special consideration during installation. Most dynamic applications can be resolved with spring-energized style seals, which often have very low friction and can be clean in place (CIP) if required.

There are different styles of springs, such as cantilever or canted coil that provide varying loads. The cantilever-style spring-energized seal provides a linear load based on deflection providing a high level of seal-ability. It can be silicone-filled to provide CIP for ease of washing, and there are a variety of materials that are FDA compliant and that work well in both viscous and pure aqueous fluids.

Canted coil spring-energized seals provide a unique feature of controlling the load the spring exhibits on the sealing element. This allows for control of a device being manipulated during a procedure.

The polymer properties give the user materials with the lowest possible friction, while still sealing in an application. The load from a canted coil spring allows the user to feel a tool in a catheter while passing the catheter through a tube, and still retaining a seal.

Eclipse’s Unique Production and Design Capabilities

Eclipse Engineering manufactures a variety of products for the medical/pharmaceutical industry. Our engineering staff designs product to meet your exact need.

We often find ourselves designing in the MRO market at small volumes to meet a user’s needs. This often occurs with equipment manufactured offshore.

Replacement parts may either have long lead times, or are not available. We often find the OEM doesn’t recognize the problem the user is having. Our design/manufacturing team will often produce a product with longer life in much shorter lead times.

When designing a product, it’s not just a case of creating a copy of what the customer is using, but understanding the need for product improvement which requires an understanding of how the equipment is utilized.

Eclipse Engineering’s staff is trained to work with the customer, to understand the application and design a replacement that will reduce critical down time while not compromising the application and its performance.

We manufacture onsite, which allows us to respond to your equipment needs in quick fashion, so you can meet your deadlines. And depending on the need, this could occur in as little as hours.

Eclipse can tool grind onsite, which allows us to design and build specialty tooling as required for a job. Our engineers are trained on most polymers that are available in the marketplace giving us the opportunity to select the right material for your particular application.

As an Employee Owned Company, our staff is dedicated to insuring your needs are met in a timely manner as they have a vested stake in the outcome. Contact us today with your next polytetrafluoroethylene seal project »

Eclipse Engineering Transitions to an ESOP

Wed, 07 Aug 2019 19:14:00 GMT

Erie, CO — Eclipse Engineering announced today that it will be joining an elite group of companies that qualify to run as an ESOP, or Employee Stock Ownership Plan. An ESOP is an employee benefit plan that allows Eclipse’s employees to have ownership interest in the company.

Transitioning to an ESOP

The plan to transition Eclipse Engineering to an ESOP began 7 years ago, when Cliff Goldstein started looking to the company’s future and his succession plan. It was at this time that Cliff started passing the torch to key employees within the organization.

Cliff: “A big part of the decision to transition to an ESOP was ensuring that nothing changed in the way Eclipse does business, from internal processes to client relationships. In many cases, when a CEO retires, the business gets sold or undergoes a massive management shift that likely changes the way the company does business.”

Cliff was adamant in maintaining the current company culture so the transition continues to be seamless for customers.

Cliff: “I wanted to ensure that regardless of my future involvement, our customers will continue to have the exact same quality products, service level, and contacts.”

Empowering Employees and Keeping the Customer First

Eclipse Engineering will continue to blaze its own trail by utilizing a management style where employees are involved in major decisions and operations of the company. Cliff founded Eclipse with the philosophy that the customer should always come first. This mission has guided all of Eclipse’s major decisions, including this most recent transition.

Cliff: “This decision makes sense, because it fits in with the mission and values of our company. An ESOP continues to keep the customer at the heart of Eclipse Engineering.”

Cliff will continue as CEO of the corporation and will also serve as Chairman of the Board. The ESOP company structure ensures that Eclipse’s employees and customers will benefit from the foundation that Cliff has built over the past 20 years.

Eclipse Engineering is a full-service seal and bearing engineering, manufacturing, and distribution company. Eclipse brings together custom engineering support coupled with manufacturing and prototyping services to offer the market unparalleled service in custom engineered solutions for demanding applications.

For more information, contact:
303-647-9750
sales@eclipseseal.com

5 Polymer Bearing Configurations and Their Advantages

Thu, 01 Aug 2019 19:45:00 GMT

Polymer wear rings were developed to offer an alternative to dissimilar metal wear rings.

One of the advantages to using a polymer material such as nylon or filled-Teflon instead of a metallic bearing is that the load may be spread out over a broader area. Whereas when you use bronze or metallic bushings, these materials are prone to point loading on the edges of the bearing.

This property of polymer bearings combined with solid lubricants can yield a product that is much less likely to damage moving components.

5 Advantages to Polymer Wear Rings

Materials for Polymer Bearing Configurations

When selecting materials, we must consider the maximum load, the speed of the system, and whether there is any lubrication in the system.

The load (or pressure over area) that the bearing will see is the first consideration. This dictates which materials will be the best fit.

It’s important to use a material that has a minimum compressive strength rating so that it will not fail under the highest loading condition. The industry standard is to employ a safety factor so that the bearing is specified to be used well beyond its design limit.

Teflon should be your first consideration due to cost and ease of installation. Nylon or composites will provide much higher load rating, but the cost and installation need to be considered.

Teflon and composites provide service without lubrication, and the composites provide excellent service in aqueous solutions. Bushings are typically used in medium to slow reciprocating service. Rotary creates challenges that may or may not work depending on the design of the bushing.

There are many series of injection molded nylon bushings. However, nylon in low-lubrication or high-loading may create high-friction, and can be noisy. Nylon, as a low-cost bushing, can be used in some high load situations.

A final consideration before going into large scale production is the cost of talking a bearing design into high production. Some bearing materials are expensive and can only be processed by machining, which limits the cost reduction scenarios at high volumes.

The Eclipse Advantage

Materials such as filled-PTFE or thermoplastics that can be molded offer cost competitive solutions for high-production applications. Eclipse provides bearings in everything from low-quantity applications, such as bridges and dams, to mid-quantity applications in aerospace .

Eclipse Engineering has experience in bearing selections based on your exact needs. Our engineers will consider all the application variables to optimize the bearing design. We also utilize all the materials mentioned and many other materials such as PEEK , UHMW , and Torlon , just to name a few.

For all your polymer needs in bearings, seals, and shapes, we’re happy to develop a solution for your application. Contact us today »

What are Clean-in-Place Seals?

Wed, 17 Jul 2019 19:35:00 GMT

Clean in place seals, or CIP seals, were developed to allow a seal to remain in place. This is especially important when the seal gland is partially open, allowing the seal to be flushed of debris.

In a food application , the same chemicals used to clean or flush the system would be used to clean the seal gland. Similarly, when other products such as pharmaceutical or adverse chemicals needed to be flushed, the CIP seal does an excellent job being open to flushing.

CIP Seal Designs and Materials

There are several styles of seals that are often found in these applications. Spring energized seals are frequently used because with this type of seal, the cantilever spring and seal groove can be filled with silicone. The silicone fills the void in the seal cavity and covers the spring, allowing the seal to be flushed.

Another typical design would be a simple lip seal without a spring. The lip can face in either direction. For CIP seals, it’s best to have the open side face the product so that during a cleaning, the complete seal is exposed. This ensures that all debris will be flushed out.

Another advantage to using either Teflon or canned lip seals is that these materials will normally be compatible with any cleaning solutions you use to flush the seal cavity.

CIP Seals and FDA Compliance

When designing for food or drug applications where the seal will be flushed, Eclipse Engineering can design with materials that may be FDA compliant both in the environment and the cleaning fluid used to flush the gland free of debris.

In special cases, double lip seals with lips facing axially in forward and reverse direction can be machined, spring energized, and filled with silicone.

Piston and Plunger CIP Seals

Eclipse also builds and integrates a piston design which has the seal built into the piston. We install a spring in the seal and use silicone to completely occupy the spring groove. This design ensures that no particles can become trapped in the seal groove, as it’s completely integrated into the design.

Piston or plunger designs for filling often take advantage of this integrated design. A typical application could be filling a cup with pudding or some other viscous media.
We often use UHMW, or Ultra High Molecular Weight Polyethylene , for its low-friction, FDA compliance, and ease of cleaning.

There are some cases where the seal is used for one type of product and discarded prior to switching to a different fill. In those cases, ease of removal into stepped glands ensures the seal can be replaced without a gland keeper, which could trap particles and contaminate a batch.

Usually upon any disassembly, a CIP seal is damaged and can no longer be cleaned. This is because the retention devices used are one piece and part of the gland, and are easily flushed with particulate.

The success or failure of a seal design is often dependent on how the seal was installed. There are many seals that easily slip into glands with simple installation procedures. But when installing seals with any volume, it’s important to have an established method to ensure consistent performance of the seal.

Discover our tips for successful seal installation »

Tips for Successful Seal Installation

Tue, 25 Jun 2019 17:12:00 GMT

We were recently asked to design installation tools for a 2-011 O-ring . At first glance, we would normally achieve this simply by using our hands. But when faced with 150,000 pieces, installation becomes fatiguing, O-rings get rolled rather than stretched in the gland, and the possibility of spiral failure over a large number of pieces becomes an eminent issue.

In this case, we chose to use a bullet which allowed the O-ring to pass over part of the installation that would tear the rubber. We also used an approved lubricant and a specially-designed pusher tool. The set was designed with ergonomics as a primary consideration to ensure that assembler fatigue did not become an issue.

An O-ring is a very simple case because it can easily be deformed to go into very small rod glands, and fit into most piston glands.

As a seal designer in polymers such as Teflon , Polyurethane, and rigid plastics like PEEK or Torlon require a change in the design characteristics to allow for installation. This can include special tools to aid in insertion, or special seal glands for ease in installation.

We typically avoiding polymers like Teflon because they often create the greatest challenges. As designers, considering installation into solid glands is an integral part in selecting a cross-section, along with the operating parameters of the application.

Specialized Installation Tools for Seals

Most PTFE blends will have elongations in excess of 100%, so using standard bullet tools over the piston along with pusher rings is a standard in the industry. These tools are easily designed and manufactured to allow the operator to push the ring over the OD of the piston.

A resizing tool is necessary to remove most of the stretch induced in the ring, and to re-size the seal so that it can be forced into the bore diameter. Some very thin cross-section rings may be installed in small volume by hand if sufficient care is given to not tear the ring. But a resizing tool is usually necessary to complete the installation.

With any volume, installation tools will ensure the seal is seated in the gland without damage.

Using screw drivers and other such tools will mar or damage the PTFE, so these should never reach the assembly table. In some cases dental floss can be used, if the cross-section is small enough and then resized into the gland.

In the case of Urethane or other polymers that exhibit some elasticity, the seal can often be stretched into the gland. While the possibility of marring the surface is less prevalent, care should still be taken not to damage the sealing surfaces of the seal.

Some of the piston-style Urethane rings may have very heavy cross sections, and the use of installation tools as described above is recommended.

Considerations for Installing Small Rod Glands

Rod glands, especially those with very small diameters, create a different set of installation problems. Looking first at O-rings, if you can reach into the gland, it’s usually very easy to slip one edge of the O-ring in the groove, and for rest of the O-ring to comply.

If the groove is too deep, or the diameter is too small to reach in, then a three-pronged tool can be used to deform the ring into a kidney shape, slide the seal into the rod bore, catch an edge and withdraw the tool. You would then use either an ID resizer tool or plastic probe to insure the seal is properly seated into the gland.

A Teflon ring will generally require turning the part into a kidney shape either in your hand or with the use of a three-pronged tool, and then sliding the seal into the seal groove and withdrawing the tool. In the case of Teflon-style rings, it’s often required that an ID resizing tool is required to gently massage the ring back to it’s round shape removing the bends produced by putting it into a kidney shape.

Tricks to Successful Seal Installation

For polymers like PTFE or Teflon, heat is powerful in softening the material to make it more pliable. The rings usually need be heated up to several hundred degrees.

Boiling water in a microwave is an effective way to soften the ring. The rings will cool very quickly, so application must be done immediately.

Where lubrication is allowed, this can often help the more elastic seals find their way. This can also be helpful even for Teflon. The only issue in the use of lubricants is that your fingers are now lubed as well.

In the process of resizing, we often put assemblies with seals on them in the freezer to help them collapse down, then install them into a bore.

Our Seal Installation Process

We are often asked to aid in developing an installation technique. We normally start with the tricks just to see what’s possible. But in general, the development of a set of installation tools normally ensures a repeatable assembly process, with no damage to the seal.

We normally design a set of tools for one application, and rarely make more than one set. This alone drives the cost of tools and why we often avoid them. However, when you consider the time spent without the proper tooling and the possibility for damaging the seal, it can be an inexpensive solution in the long run.

We didn’t discuss installing Spring energized seals in solid glands because this is rarely done due to how easy it is to damage the lip or deform the cross section. This can be done in rare cases, but typically the seal is installed into two-piece or stepped glands.

Eclipse designs and manufactures installation tools for most seal applications, as well as taking a customer’s hardware and designing methods for installation. We are constantly improving tools and methods for installation.

We are also always looking for ways to improve our customer service and lead-times. Discover how we maintain minimal lead time with every seal »

How AMS3678 Ensures Consistency in Sealing Materials

Mon, 17 Jun 2019 16:54:00 GMT

When it comes to designing and developing seals, the aerospace and industrial industries need a basis to allow production anywhere in the world.

One of the first PTFE (Teflon) standards, AMS3678, describes Teflon and the addition of fillers. This was used in conjunction with Mil-R-8791, which is one of the Mil specs describing a backup ring device.

The origin of all these specs dates back to the creation of the O-ring .

The Origin of the O-Ring Patent

In 1939, Niels A. Christensen was granted a U.S. Patent for “new and useful improvements in packings and the like for power cylinders.” These referred to improved packing rings made of “solid rubber or rubber composition very dense and yet possessive of great liveliness and compressibility.” These products were suitable for use as packings for fluid medium pistons (liquid or air). The improved packing ring is the modern O-ring.

There was a progression of standards for the O-rings created by individual countries, such as AS568, BS 1806, DIN 3771, JIS B2401, NF T47-501, and SMS 1586. Eventually, AS568 became more accepted in the industry.

The backup ring was originally created to help improve the O-ring’s ability to resist extrusion. Teflon was widely used as one of the materials for backup ring devices. Standards were created to unify the production of this Teflon device.

The Progression of Mil Specs

We accept purchase orders on a regular basis for Mil-R-8791 and other mil specs of a similar vintage, describing Teflon and its fillers used in seals and backup ring devices.

The progression of standard changes has led to AMS3678/1 for Virgin PTFE through AMS3678/16. These standards describe a group of Virgin- and filled-PTFE materials accepted by the industry for manufacturing seals and back-up ring devices.

Mil-R-8791 was canceled in February 1982. This spec was superseded with AS8791, which eventually evolved into AMS3678.

AMS3678 is a tool used by customers and Teflon suppliers to create uniformity in the manufacturing and processing of seal and bearing materials. The standard is inclusive of most of the compounds upon which the industry was built.

When our customers approach us with an old “mil spec”, we push the certification to the new AMS spec which is currently active. Eclipse manufactures to the spec so our customers will have the confidence that we manufacture to a known standard.

When we cross custom materials from well-known sources, we drive the customer to an accepted spec that is equivalent to the original source of the material. This helps our customers sell their products with internationally-known materials rather than custom, home-grown compounds that are often intended to single source those materials.

There are several qualifications of the spec that we as suppliers must observe. This includes dimensional stability tests. This test ensures the material has been properly annealed, and that the seal or backup ring will fit and function as it was originally intended.

Eclipse is uniquely qualified to supply parts to the latest AMS3678 specification. We understand the scope of the specification which allows us to ship parts with fully traceable certification.

AMS3678 helps validate a material to a customer to ensure they get the same material processed the same way with each order. Beyond this, there are other ways to determine what makes a part process-capable.

Discover what makes a machining operation or a specific dimension process-capable »

What Makes a Part Process-Capable?

Tue, 21 May 2019 15:50:00 GMT

Machining plastics is as much a skill as it is an art form. It takes understanding that whenever you cut a part, it will probably have some motion or energy still within the material.

This is largely because our parts have more rebound than steel in the cutting process. And while plastics are mostly thermally stable, they’re not dimensionally, thermally stable.

Changes in temperature from the time the part is machined, inventoried, and put into service show that our parts are constantly changing in size. PTFE or Teflon suffer the greatest change in thermal instability where we machine the part, around 74 degrees Fahrenheit.

What Makes a Machining Operation or a Specific Dimension Process-Capable?

You might think that if you can make a part and verify that it’s intolerance, then the part is process-capable. But the reality is that a large tolerance range doesn’t make a part process-capable.

At Eclipse, we implement a rigorous process to ensure parts remain process-capable after machining is complete.

By measuring the parts after a run and reviewing all the critical dimensions, we find standard deviation for a dimension. We then can estimate with a high degree of certainty if, during the process, we will have parts with dimensions that will fall outside the tolerance range.

Our experience with this process helps ensure accuracy. But without doing an actual analysis based on real parts that we would run on a job, we can’t know with complete certainty if a particular dimension will be within tolerance.

One thing is certain: If you dimension a plastic part and apply metal tolerances, we will most certainly fall outside the process-capable range for that part.

Certain materials like PEEK will hold tolerance during a machining run far better that Teflon. But there are some dimensions we hold in Teflon which can be maintained to a high degree.

Usually, if we design a part with our standard manufacturing tolerances, it will certainly have a bigger tolerance range than if we design with steel. Most often, making the tolerance range smaller has little to no impact on plastic parts. Under pressure, the parts get pushed around, and are constantly changing shape to some degree.

So why bother with tolerancing at all?

We design to fit the application, so our products have to fit into the required hardware. And depending on the type of elastomer, we may need to hold tolerances on a particular dimension so the seal will perform in the entire range in which a customer wants to use it.

What Is and Isn’t Critical

When we look at why a seal preforms, the wall dimension (cross-section) generally has the most influence on success or failure. This is due to the seal being energized by either an O-ring or a spring , and the impact of the extrusion gap on the sealing system.

The width is usually the second most important factor, as the seal must be able to move freely in the gland. The least important dimension is usually the diameter. We need the seal to sit in the gland so that it can be assembled; but in general, this is the one dimension in which you’ll see the greatest change due to temperature.

Unless the application is operating in a very cold environment, the diameter must allow the seal to sit in the gland and not protrude too much for installation. Tolerances on large diameter seals (over a couple of feet) often are +/-.060 inch. This may seem like a lot, but throw in a little temperature and you find that fluctuation at this scale isn’t impossible.

How Do We Determine Process Capability?

The use of process capability calculations became common for suppliers to the automotive industry due to the large quantity of parts being made, and the need for upper-tier suppliers to know with certainty that they were getting good product.

A process capability study will tell you how likely the process is to make a good part. We won’t go into the statistical formulas in this article, but it’s enough to know that given dimensional data from a run, we can use the equations to find out a number that will indicate how likely we are to meet print tolerances.

The main index that we look at is labeled “Cpk”. The Cpk is calculated for critical dimensions using the tolerance limits and the data from a sample run. The higher the Cpk value, the more capable the process and the likelihood of making good parts.

Industry standards aim for a value of 1.33 for industrial parts and 1.67 for aerospace . In order for a process to reach high Cpk levels, the parts must be made using a small portion of the tolerance range and run at the middle of that range.

Generally speaking, a Cpk less than 1.0 indicates that the process isn’t capable, and is likely to produce parts that are out of print tolerance.

Process Capability Put to Use

How do we make use of Cpk? In practice, the machinery, tools, and processes are all known well before a part is designed. So putting a non-capable tolerance on a print will place undue burden on the inspection required to supply parts to that print.

A much better approach is to consider the capability of the process first, allow for that variation, and then design the part to accommodate the required tolerance. Having run Cpk on all our processes, Eclipse has an excellent understanding of what is process-capable and uses that knowledge to design and manufacture seals accordingly. In the case of customer-designed parts, we offer process-capable tolerancing in our quotes.

Learn more about our seal processes and the industries we serve »

Which Sealing Materials Meet FDA Compliance?

Thu, 16 May 2019 15:24:00 GMT

We frequently get requests from customers asking for FDA-certified materials. The FDA doesn’t approve materials, but they do approve a device which contains materials that we make seals from. These materials find themselves on a compliant list from which we manufacture seals.

The FDA doesn’t approve a material for an FDA application unless it’s specifically submitted to the FDA for approval. However, some materials have been tested in applications containing materials from which we manufacture seals.

The short list of raw materials are found to be compliant by the FDA of provided materials because they don’t react in a negative way when used in specific FDA-approved applications. These materials become compliant, meaning they were found to not react in a specific set of circumstances.

When we design a product for a food-grade application , we select materials that fall into this specific category of compliance. The reason the FDA will not “approve” any particular material is because that material may be fine when mixed with, for example, baking soda, but may be found to react violently with soda pop.

However, a piece of equipment with a seal for a soda pop application could be compliant with a totally different piece of equipment that was also being used with soda. The equipment, machinery, and process must all be considered in order to operate in an FDA-compliant fashion.

Testing for FDA approval can be an expensive proposition. Customers usually aim for compliance unless there’s a regulation that requires FDA approval.

As a seal supplier, we defer to the customer with a list of known compliant materials for use in applications that come under FDA compliance guidelines. Our customers provide information on the equipment and processes used, as well as the industry requirements. Ultimately, it’s our customer who takes responsibility for approval to a governing body.

This may seem to be a less-than-adequate position from the customer’s point of view. However, if the customer has knowledge regarding the use for their material, Eclipse can generally do the necessary research to verify compliance in a specific application.

FDA Compliant Materials

Some of the more popularly used and highly published materials that fall under FDA compliance are Virgin PTFE and any grade of unfilled Teflon, Tefzel, and TFM that fall in the fluoropolymer family.

Materials such as UHMW (Ultra High Molecular Weight Polyethylene) are also FDA compliant. Many of these materials fall under a Code of Federal Regulations. Two specific areas are 21CFR177.xxx, and 21CFR178.xxx

There are a number of urethanes, rubber products, and polyester elastomer products that also carry compliance. Most elastomers, like O-Rings , can be made to be FDA compliant.

We often use clean-in-place style seals, or CIP, in food-grade applications .
This often requires we fill the spring cavity with an FDA compliant silicone that allows the spring to continue to work without becoming filled with food substance. CIP seals are a good way to allow the operator to clean a seal without removing it from the hardware.

In rotary service, we design seals that typically are holding lubricant from gear boxes or drive systems away from the product. These seals can be built with multiple lips, keeping product and lubricant separated. Eclipse can also provide seals that are pre-packed with FDA compliant grease.

We use fillers in PTFE to help extend the wear life while not appreciably raising the coefficient of friction. The fillers also have FDA compliance. There are many fillers that work well on soft stainless shafts and provide strong sealing and long life.

The technology for sealing in areas where FDA compliance is required requires a good understanding of the intended application and goal. And while a portion of a system may fall under the compliance regulations, many components that don’t come in contact with the product don’t require compliance in the product side of the application.

Eclipse Engineering designs seals for a variety of environments that require special consideration to materials as it applies to sealing.

Bearings are always a part of any sealing system, and must be considered when designing in these FDA compliant applications. The same materials we design seals from can be used to help support hardware.

The major caveat is bearing placement — it’s important to ensure that if the bearing comes into contact with the product, it can be easily cleaned in order to maintain a contaminant-free environment. Even though a bearing may be solid, the clearances required for installation may still allow the product to migrate under the bearing, so seals must be used to protect the bearing from coming in contact with the product.

Eclipse Engineering designs and manufactures seals and bearings in environments that must meet federal guidelines or FDA compliance. Contact us to discuss your sealing application needs »

Temperature Ranges for Various Materials: NBR to PTFE

Wed, 24 Apr 2019 14:39:00 GMT

Sealing materials are selected for many different reasons. The application dictates the style of sealing. But fluids, pressures, and cycle times all play a prominent role in seal and material selection.

When we add in temperature, this factor often directs us to the types of materials that can survive the application. Read on to learn how we choose sealing materials based on operating and interface temperatures.

Sealing Material Applications

Let’s start out with the most basic material, NBR or Buna-n rubber. The standard temperature range for this material is -40F to 250F. With compounding, this range can be extended to -65 and 300F, but rarely operates at both extremes — and always as a special compound.

With rubber compounds, we must always be cognizant of the fluid in contact to ensure chemical compatibility. It’s important to note that rubber contact seals are best suited for static applications.

Other elastomers, such as silicone, normally travel between -65 and 450F — but don’t handle hydrocarbon fluids. Switching to fluorosilicone has a broader temperature range of -100 to 350 or 400F, and handles hydrocarbon fluids. In this case, availability becomes a problem.

When we talk about elastomers in sealing, the user must be selective within a range of factors. The temperature boundaries can often create other problems in elastomers, such as compression set or swell when combined with fluids.

We use elastomers in sealing as a primary seal and often as a secondary seal in a system. Even if the seal is static, it can still suffer from issues of elevated or frigid temperatures.

Polymer Materials

Polymer materials open a wide range of sealing possibilities. But even the most rigid of polymers needs to remain flexible throughout its operating range and chemically compatible.

While polymers like Teflon can operate between -400 and 500F, there are many physical changes that cause the material to either be too rigid to seal or have such a large loss of physical properties that it could become useless in an application.

An example would be Ultra High Molecular Weight Polyethylene , UHMW, which provides great sealing in air and water and many chemicals but loses structural integrity above 180F. Urethanes are up in the 300F.

We have sealing applications that exceed 1000F and we often turn to carbon seals like the triple ring seal. The requirements for long life are often care in manufacturing the gland with excellent surface finishes.

If all our sealing will occur over 700F and there’s no oxygen present, Polyimide materials often do an excellent job. But as temperatures cool, this material becomes less compliant.

PCTFE

Want to go to -460F (close to absolute zero), Polychlorotrifluoroethylene, or PCTFE is what you’re looking for. The caveat to all these polymers with temperatures that exceed the ability of most elastomers are metal springs.

Eclipse Engineering designs seals from the application up. The use of elastomers, polymers, carbon, and metal springs are just a few of the tools we use to solve sealing problems.

In designs where we can see over 700-degree temperature swing, it’s important to realize the interaction of the seal with the hardware. As the hardware is going through these swings, we must accommodate the growth and shrinkage of dissimilar materials when designing a sealing solution.

Having a full range of materials allows us to design solutions for your specific needs. The engineering staff at Eclipse has experience with all the materials mentioned to create a solution specific to your needs.

We also manufacture using various grades of elastomers, custom blending of any of the polymers to handle varying amounts of temperature change with spring candidates ranging from a simple Buna-n O-ring to a sophisticated spring energized seal.

Learn more about our sealing materials and applications »

How Material and Spring Type Affect Friction Calculation

Mon, 15 Apr 2019 17:47:00 GMT

This article will discuss how we understand and control friction in dynamic sealing applications.

It’s easy to stop a leak in a system by just welding it shut. But when you create a dynamic application, you generally have a limited amount of power to move the device you’re sealing.

Friction is a force that must be overcome in all moving pieces. Controlling friction allows us to make efficient equipment that can have a long wear life and move with a limited amount of force.

There are many factors that drive friction up or down in a dynamic application. Although this blog will focus on shaft seals, the same considerations apply to piston or face seals.

Below we’ll cover the following factors and how they affect the friction calculation in our seals:

Seal Substrate

As a seal supplier, we usually like shaft materials to be hardened steel with surface finishes that are highly effective. Hardness above 50 Rc usually gives long wear life.

Having a good finish of 8 Ra. will insure long seal life and carry lubrication. However, depending on the application, there are times when a super finish of 2 or 3 Ra is justified.

Depending on shaft loading, there are many choices of surface finish that can reduce friction and improve the life of the seal. Understanding the bearing load under the seal helps to understand what finish is required to withstand the operating conditions.

There are some finishes that are detrimental to seal life. An example is a heavy chrome surface that looks sturdy, but usually can’t be ground smooth and is left with large peaks or valleys. Thin, dense chrome is often the opposite, giving good seal life if applied correctly. The engineers at Eclipse Engineering are prepared to make recommendations on hardness and finish.

Lubrication

Lubrication helps to reduce friction, especially if the seal interface is rubber or an elastomer, such as urethane.

We often operate in environments which are dry and intolerant of any form of lubrication. In this case, seal material such as PTFE or Teflon can operate dry while keeping frictional forces to a minimum and still insure long life.

Water is typically not a very good lubricant. But water-based coolants or adding ethylene glycol improve lubricity, like in your cooling system in your car. Seals often operate in very abrasive fluids such as paint, which contains solids.

This combination requires using materials that don’t degrade in the fluid and don’t heat up or deteriorate. By selecting these materials, we can lower friction and improve the life of the seal.

System Pressure

Pressure directly impacts friction at the seal interface. By looking at the contact area at the interface, we can add the load of the pressure into our friction calculations.

The secret to lowering the friction at the interface is the amount of contact the seal has at the interface.

There are many styles of seals that allow us to minimize this contact patch while providing excellent seal-ability. PTFE or Teflon doesn’t provide “perfect” sealing, but its coefficient of friction is lower than most other materials. By combining seals, we can create sealing systems that have extremely low frictional forces under very high pressures.

Using secondary seals with elastomeric contact allows these seals to operate at very low pressures and give long life. These systems lower friction, heat, and extend seal life.

Operating Temperature

As temperature rises, the coefficient of friction also rises. The increased temperature causes seals to wear faster, causing other seals in the system to heat up.

Limiting the seal interface and using materials that reduce friction lower the overall bulk temperature in a system. By varying the spring or elastomer force, we can reduce the load on the seal lip so that at zero pressure, the seal can have the lowest possible friction while still sealing. All these factors reduce temperature, thereby reducing the effective coefficient of friction in the sealing system.

Seal Materials and Fillers

Materials have a great impact on friction. Changing the material of the seal will also change the sealing characteristics.

A rubber or urethane style seal often results in a zero-leak seal with very high friction. At the same time, using a highly-filled PTFE seal will often result in a very low friction seal that may have a small amount of seepage.

Materials like Teflon provide the lowest friction possible. When used in combination with elastomeric seals, this material can provide a zero-leak system with dramatically reduced friction.

Fillers in elastomeric seals can often reduce the interface friction by adding lubricity to the contact patch. When adding fillers to Teflon, we normally see a small increase in the coefficient of friction. This minor increase dramatically improves the wear life Teflon filled materials.

Energizers

Elastomeric seals normally provide energy through interference and the rebound quality of the material. One way to change the friction is to reduce the interference of the elastomeric seal, but you may sacrifice seal-ability.

Materials like UHMW or Teflon need an external source of energy in order to seal when the pressures are below 100 psi. These materials could be energized with elastomers like O-Rings , or metallic springs like Cantilever Beam or Canted Coil Springs to energize the seal lips.

Eclipse Engineering designs and manufactures spring and can tune the spring to meet friction and leakage requirements.

In rubber energized seals, changing durometer will alter the spring force generated on the seal material. However, sourcing non-standard elastomers can be a problem. These varying energizers are a direct impact on a zero or near-zero pressure system, and becomes an additive force when applying pressure.

There are many factors that directly impact how friction can be controlled. The design engineers at Eclipse Engineering understand these factors thoroughly, and design to the customer’s application. We select components and systems that couple with requirements to solve customer sealing applications. Contact Eclipse Engineering to get the best sealing solution for your application »

How We Maintain Minimal Lead Time with Every Seal

Mon, 25 Mar 2019 20:08:00 GMT

Have you ever ordered a burger in the drive-thru, parked your car, and sat waiting for your food to come out while the 3 cars behind you have already come and gone?

Now imagine pulling up to a seal manufacturer window and placing your order. The customer service rep cheerfully tells you that since you’re not a AAA member, it’ll be 12-16 weeks to get your order. And if you want a special, that’ll be 20 weeks.

Lead times are a necessary part of manufacturing to plan jobs and prepare raw material for processing into your job. During that time, items like contract review, programming, and scheduling are taking place.

The AAA customer gets their normal 4-6 week lead time, depending on their jobs. Meanwhile, all other customers are siphoned into the “we’ll get to it when we can” lead time category, which is usually around 12-16 weeks.

How We Maintain Faster Lead Time

At Eclipse, we attempt to schedule every job in the sequence that it was received. However, we recognize that there are times when something didn’t go as planned on the customer’s side, which necessitates shuffling jobs around to accommodate an expedited order.

This scenario may seem like common sense, but it’s a service that’s not as common as you might expect. When the phone rings and a customer tells us they’ve got an issue with our seal, we understand that it’s not just our seal, it’s our customer and their needs at stake.

This is not extraordinary service, this is just business the way it’s supposed to be — like getting your burger the way you want it.

How are we able to maintain faster lead time for our customers? By outsourcing and stocking critical materials, customizing and properly maintaining our tools, and staffing efficient sealing experts to make sure you get a quality product quickly.

Outsourcing and Stocking Materials

We’re able to maintain minimum lead times by double or triple sourcing hard-to-get materials, as well as keeping enough tooling on hand to take care of customer emergencies. With critical materials, we keep our own level of safety stock to ensure we can respond to emergencies if they occur.

Customizing Our Tools for Custom Jobs

We understand that all equipment requires maintenance, which can result in our manufacturing equipment being down for a period. It’s important for us to maintain a seamless process and not get in the way of putting quality seals in your hands in a timely fashion.

On critical pieces of equipment, we have duplicate manufacturing capability to ensure our customers are taken care of in these situations.

We also have the ability to grind any special tool required for jobs we manufacture in-house.

Staffing Efficient Sealing Experts

We estimate Eclipse delivers around 1 million seals per year to customers all over the world, and it’s done in a timely manner to ensure customer satisfaction with a quality product.

What sets us apart are the people that make up Eclipse Engineering. Eclipse is made up of a group of people who take responsibility for taking care of the customer first.

That means ensuring that your order or request is handled expeditiously so that you can give your customers the information they need to keep scheduling and building cycles on time.

Our goal as a supplier is to ensure that you spend the least amount of time possible dealing with processing and following up on orders. We promise that someone will answer the phone and/or your web request in a timely manner so you can focus on your business.

Richard Branson once said , “Train people well enough so they can leave, treat them well enough so they don’t want to [leave]. Take care of your employees and they will take care of your business. Loyal employees are our greatest assets — not liabilities.”

This is the basis for why Eclipse Engineering will always excel as your seal supplier.

Designing Cryogenic Seals for High and Low Temperature Sealing

Tue, 19 Mar 2019 19:44:00 GMT

When designing for low temperature sealing, the first step is to define the temperature range that the seal will be operating in.

We typically define cryogenic as seals operating below -65 Fahrenheit. We pick this point because we currently have elastomers that have a usable TR10 value at this temperature.

When designing at this level — with high temperatures around 300 Fahrenheit — an understanding of what level of leakage control is required on the low temp end. Seals that operate in aircrafts must function within this range.

However, there may be an allowable leakage rate which allows for reduced drag. When requiring zero leak, the drag in the system is often increased to support some elastomeric contact with a dynamic surface. In the case of static seals, elastomers span this range although increased squeeze may be necessary.

Eclipse Engineering routinely designs in the range indicated above.

While -65 Fahrenheit is extreme cold, we don’t consider this cryogenic. Liquid nitrogen at -320° Fahrenheit (-195°Celsius), requires special hardware and seal material consideration.

To begin, we often find ourselves sealing with no lubricant in dynamic applications. To improve sealability, a better-than-average surface finish is required.

Surface finish often holds lubricity. But without this, a smooth finish reduces friction, improves life, lowers drag, and improves sealability.

Static seals are often required to have leak rates approaching zero; meaning hardware considerations and surface can be even more important. This may mean polishing the groove, which in some applications can be very challenging.

Cryogenic Seal Materials

The next criteria are the seal materials. Elastomeric materials lose their flexibility at these extreme temperatures, and so we rely on polymer type materials to bridge the gap. When we experience temperatures below -180° Fahrenheit ( -195° Celsius), we begin to move away from basic PTFE to modified fluoropolymers such as PCTFE, known for operating down to -460 Fahrenheit.

We try to keep fillers from very little to none. (Fillers extend wear life of these polymers). These materials require some kind of spring force to activate them, as they have very poor memory. They also require an energizer to force them in contact with the mating surfaces.

Propper material selection is only a partial resolution to maintaining a seal, as special cross section designs are necessary to reduce the amount of force required to move the material at these extreme temperatures.

When you consider the pressures we may be sealing, back up rings also become necessary if the cross sections become too narrow. We typically design these cross sections around a spring that forces the seal in conformance with the hardware.

Special consideration is given to the spring material — not just for chemical compatibility, but also tensile strength which provides the forces to push the seal material out.

Cryogenic Seal Types

Eclipse Engineering designs with a variety of spring types such as cantilever , canted coil, helical , and raco. We also design in a variety of materials such as various grades of stainless, hastelloy, elgiloy, and inconel.

These materials and spring types allow us a great deal of flexibility in conforming to a customer’s hardware envelope.

Cryogenic Seal Jacket Material

A final consideration is the machined surface finish of the seal jacket material. Eclipse Engineering has developed a process of “super finishing” our polymer materials to allow them to seal on installation.

We have found that many of these cryogenic applications typically don’t have high amount of dynamic motion, so break in may not be possible. Super finish allows the seals to have the best chance of sealing right out of the box.

Some typical applications in cryogenic applications include liquid oxygen or nitrogen valving. If we need to meter flow, the effects of friction become a very relevant factor, as customers often have limited space and limited force to open and close valves.

Eclipse has the ability to estimate friction forces knowing the spring rates and the coefficient of friction of the materials we seal with. Having all these pieces in place insures we perform well in these extreme conditions.

Normally, we are required to seal from 70° Fahrenheit down to these cryogenic temperatures, but sometimes we must extend to range to 100s of degrees Fahrenheit. Special consideration must be given to how much spring force we can apply, as too much can cause cold flow of the polymer, rendering the seal inoperative when it returns to cold temperatures.

Sealing cryogenics is a balancing act of many factors such as spring force, surface finish, friction and allowable leakage.

Eclipse Engineering has proven applications performing for over 20 years in these harsh sealing environments. Contact our engineering staff today with any questions about your sealing projects or applications »

Eclipse Engineering Turns 20 Years Old

Thu, 14 Mar 2019 22:13:00 GMT

20 years ago, Eclipse Engineering opened its doors to the public.

Eclipse Engineering got its start filling the industry need for quick-turn, tight-precision polymer and metal parts. Because our background was in seals, previous customers from other business relationships migrated to us, asking us to either reverse-engineer sealing solutions, or solve problems that other seal suppliers had struggled with.

At our inception, we had close ties with Jemco Seal. Jemco sold Mechanical Face Seals, repaired mechanical face seals and sold polymer seals including Teflon and O-Rings .

As a seal distributor co-located in the same business park, our relationship grew to the point that we began machining polymers for some of their customers in the Colorado region.

Eclipse eventually purchased inventory and the polymer seal portion of Jemco Seal. This action drove Eclipse out of make-to-print parts, and into the seal manufacturing business. Coming from a seal background, it was only natural to gravitate back into this business.

As we looked to start a new business, we needed something special to offer customers that would exceed their expectations as a seal supplier in a world where large seal suppliers dominated the business.

Eclipse is built on a philosophy that if we take care of our customers’ needs first, all our needs internally will be met. We realized we had to have a product that solved customers’ problems without burdening the customer with problems occurring at a manufacturing level.

This seems like incredibly simple approach in business that is often overlooked because it’s so basic. In fact, in the late 80’s through the 90’s, large OEM manufactures talked about customer service and how to put the customer in the forefront of the supply chain.

But these words often were drowned out by corporate mandates on what needed to happen to improve profitability and efficiency — often at the expense of the customers’ needs.

In this regard, Eclipse Engineering was no different than any other manufacture: if you didn’t turn a profit efficiently, your business would eventually run out of money and you’d be out of business.

Focusing on the customer and not on profitability or trying to rush the customers’ problem out the back door means that when we place a new design into production, following up to ensure that we didn’t push a problem on their line down the road allowed us to grow our business vertically with one customer.

Our first products were simple products supplying simple seals and bearings into an industrial market. Variations of rod and piston seals along with sealing systems including bearings were our early beginning products.

Our customers asked us to begin supplying spring energized seals next. In our development, we built Eclipse on being self-reliant so we wouldn’t need outside suppliers for manufacturing needs. As such, the manufacturing tooling for spring energized seals was already in place.

All Eclipse springs are welded to allow equal forces on the seal jacket. While this seems rudimentary, we repaired many seal applications where our competitors didn’t weld springs, causing inconsistent loading on the seal jacket and allowing for leakage.

Our customers then asked for different styles of springs and with different materials. Eclipse Engineering supplies cantilever , helical, and the raco springs in all cross sections.

Canted coil was the next request from customers, and while these products are available to purchase, we were asked to supply custom canted coil springs. Eclipse developed its own method for producing canted coil spring allowing customers to request any load they needed along with materials, that compliant with the working environment. And of course, all were welded.

Eclipse supplies seals that are FDA compliant, using materials that are safe for food and beverage and medical equipment applications . We have seals for CIP (clean in place), including spring energized seals that are silicone filled.

In addition to rod, piston, and face seals, we began to offer products that seal on off-axis hardware, such as ball valves. Our customer asked us to develop a cased Teflon seal that was much smaller than the standard offerings for lip seals. Eclipse developed the MicroLip, allowing for small seal cross sections never seen in the lip seal market.

Eclipse’s design staff helps customers develop their hardware to improve manufacturing for our customers, while providing sealing solutions complimentary to customers’ needs.

The quality standard ISO 9000 is necessary to operate in our manufacturing climate. Becoming AS9100 provided the opportunity to provide products for the aerospace and military market. We’ve been supplying products for this market for over 10 years.

From the bottom of the ocean in the oil and gas industry to our industrial world in food, pharmaceutical, farming, and medicine, Eclipse Engineering continues to develop solutions unique to these industries. We’ve have had continuous and steady growth since our inception due to our basic philosophy of placing our customers’ needs first.

To all our customers, thank you for the opportunity.

The Advantages of Crimped Can Seals

Tue, 12 Feb 2019 21:52:00 GMT

Rotary seals are often secured in sealing hardware by crimping the sealing element in a metal can. One of the most common rotary seals is a molded rubber lip seal in a can.

While not crimped, the can retains the sealing element, and stops the seal from rotating in the gland. Rotary sealing elements for low pressure (under 15 psi), are often nitrile or Viton rubber sealing elements.

This style of seal comes in many cross sections, and may include garter springs to help the seal stay engaged with the shaft. These seals are typically low in cost, and produced in high volume.

These seals are found in many low-pressure applications. However, as the pressures begin to climb over 10 psi and speeds run over 500 ft/min, friction generates heat, which accelerates wear on the rubber element and in turn begins to wear the mating shaft material.

Overcoming Friction

Friction or the resultant heat is the largest concern in rotary service.

The crimped can seal with PTFE (Teflon) elements can run with pressures in excess of 500 Psi and PV (pressure- velocity) reaching over 350,000psi-ft/ min. The crimped can allows these elements to remain secure.

The crimped case seal causes all the relative motion to remain at the sealing lip interface. With the crimped can, we have the opportunity to install multiple lips or seal cross sections to handle a variety of loads. This allows us to control leakage, and keep friction to a minimum.

We can seal most any fluid or run dry sealing gases with little or no lubrication. With widely varying temperatures, we can include springs to maintain seal contact, offset some eccentricity of shafts, keep dirt out or keep very light loads.

Adding a Spring to Crimped Case Seals

With the help of a spring, the crimped case seal may seal pressures and vacuum in the same cavity. We can even seal low-pressure with the lips facing backward, while excluding other fluids into the system.

The beauty of the crimped case seal is that it can be manufactured to meet your requirements, when your needs exceed the very common rubber lip seal.

Eclipse Engineering manufactures crimped rotary lip seals with inside diameters from under .060 to over 25 inches in diameter.

The MicroLip Seal

Our latest product, the MicroLip , allows for extremely small cross sections. This product also offers a new variety of spring combinations and retention methods that haven’t been seen in the sealing industry before.

MicroLips are produced with a variety of materials to accommodate shafts with hardness in the “B” scale. We’ve even developed a MicroLip that seals on the OD surface, instead of just the ID.

Different Materials of Crimped Can Seals

We can manufacture seals in most metals. As an OEM, we can manufacture small volume quantities or amounts into the thousands.

This style of seal allows cost savings in remote hydraulic motors, allowing the removal of the case drain hose. It can also be installed using an O-Ring in the hardware to improve removal and installation of the seal.

It can be supplied in an external cartridge for ease in field replacement — although this seal with the correct design is fairly easy to remove and replace in standard rubber lip seal hardware. It can be supplied with exterior coatings to help improve seal-ability on the static side for compromised hardware.

Rotary lip seals using Teflon elements offer the user many options in sealing. The MicroLip allows for low profile seal ability.

A variety of fluids and temperatures affords the user a broad operating envelope in one package, handling pressures from vacuum to 500 PSI. This combination of crimped can seals will handle a variety of applications when a rubber lip seal is not your solution.

Feel free to contact us with any seal questions or requests »

Why Eclipse Engineering Exceeds as Your Seal Distributor

Wed, 06 Feb 2019 22:26:00 GMT

At Eclipse, reliability is not an accident. Our customers’ expectation is that each seal we design and manufacture is to print, and meets the quality requirements that are specified.

Quality and reliability are part of who we are. Our culture at Eclipse Engineering is to place our customers at the center of our purpose. If we succeed in satisfying our customer, we will succeed in our goals.

Seals are always a part of a system to retain or exclude a fluid. A method for improving reliability is creating sub-assemblies, or cartridges, which retain the seal with other components.

Installation is improved because there’s little or no chance of seal damage. And field replacement can be accomplished by cartridge replacement again, allowing for improvement of repaired units without risk of seal damage.

Single Source for All Components

At Eclipse, we often source all the components, build the seals and build up the sub assembly. This reduces part count for the OEM, reducing the overall cost of the end product due to sub assembly build up and installation.

We Handle Repackaging and Reselling

We can also package for resale of our OEM’s, preparing the product to move from the shelf into the rebuilder’s hands, with a high probability that the rebuild will be successful.

Eclipse prepares kits for OEM resale into the rebuild market, saving time and resources by pulling all the soft replaceable components for seal rebuild. We can manage the purchasing of all the components and brand package for resale.

O-Rings can be dotted or individually packaged, or tagged for easy identification for the end customer during their build cycle.

As an authorized DuPont Kalrez distributor, we can supply genuine Kalrez products in their original packaging. They can be supplied individually or packaged in kits for resale.

Certification, Delivery and Inventory Maintenance

Certification of products is available depending what the requirements are.
Products can be dropped shipped anywhere in the world.

We also can plan delivery and maintain inventory to smooth out manufacturing insuring products will always be available regardless of the production schedules.

Reliability, delivery, quality, and price will continue to be our customers focal point. Contact us today with any customer service question or need »

The Best Uses of UHMW Seals and Bearings

Tue, 29 Jan 2019 21:43:00 GMT

Ultra-High Molecular Weight Polyethylene , or UHMW, is an inexpensive easy to acquire seal material which, in the right environment, provides an excellent seal.

There are a set of operating criteria designers must follow to take advantage of the many benefits that other materials like PTFE can’t offer.

In this article, we’ll explore the uses of UHMW, how and where to apply it, and the pitfalls to avoid.

What are the Best Uses for UHMW?

UHMW is used in a variety of seal and bearing applications.

As a bearing, UHMW is used in many linear applications with both oil or dry environments. But it’s especially useful in low-load water applications, as UHMW will “wet” due to its hydroscopic nature in water.

Materials like PTFE are hydrophobic, meaning they tend to shed water. This causes water or aqueous solutions to be abrasive to materials like PTFE.

Here are a few most popular uses for UHMW seals and bearings:

Guide for ski gondolas

Low-load cylinders

Spring energized seals

Sealing paint

Air cylinders

Joint replacements

We typically don’t use UHMW in rotary applications due to high loading, and the creation of localized heating which can quickly distort the material and reduce its ability to seal.

However, in very slow rotary or oscillatory applications, it can provide an excellent seal in the correct environments.

Installation Considerations for UHMW

UHMW has little memory, so stretching during installation can be a problem.

Typical spring energized seals are normally installed in two-piece glands or stepped glands.

With the proper interference, this material can act as a scraper as well as seal to keep systems clean in mild abrasive environments.

We see spring energized UHMW seals in a variety of applications, such as pump seals in two-part adhesive systems, or pumping two-part urethane into the mixing heads.

They are also often found in air cylinders where an O-Ring provides too much hysteresis or friction in the motion of the cylinder.

Guides in water or seals where glycol or aqueous solutions are the media cause UHMW seals to be the material of choice.

UHMW must be properly supported or it tends to yield or “smear” over a surface if it’s too heavily loaded. Also, it has a stringent temperature limitation of below 160F with brief excursions, and light loads to 200F.

UHMW machines easily, which keeps costs down. But in small parts the chips can create a problem due to the stringiness of the material.

Improving the Life of UHMW

To Improve UHMW against wear resistance, certain additives are available to extend the life of the material.

Some of the fillers include surfactant to improve lubricity, or yellow dies which improve wear. Ceramics which can also extend the life of UHMW by as much as 10X.

In the correct applications, UHMW provides an excellent seal material — especially against solids or aqueous-based solutions at medium temperatures below 160F.

As a spring energized seal, it provides excellent scrapping ability, and a very positive seal.

Learn more about Eclipse’s spring energize seal types »

Benefits, Features and Best Applications for Torlon

Thu, 20 Dec 2018 20:51:00 GMT

Torlon® polyamide-imide is one of the highest performance thermoplastics that is still melt processible.

Torlon can be extruded into shapes and injection molded into custom geometries. With a 500°F heat distortion temperature (softening temperature) and a 500°F continuous service temperature, Torlon allows for usage at elevated temperatures while maintaining its strength.

It’s stronger at 400°F than many other engineering resins at room temperature. Torlon is also tougher and more impact-resistant at cryogenic temperatures than other high strength polymers.

Its properties are the result of being transformed from a thermoplastic to a cross-linked thermoset during an extended curing process.

Glass-reinforced and carbon fiber reinforced grades offer even greater stiffness plus enhanced thermal expansion properties.

The various wear grades of Torlon offer unmatched performance over a wide range of temperature and PV values. *

Our Applications of Torlon

We apply Torlon to many applications that can be structural or as a part of an assembly with a PTFE-style seal.

Its ability to resist distortion under high temperature makes it an ideal material for under the hood componentry.

We’ve made snap rings from Torlon allowing for a retention method in a high temperature application where installation will not scratch or abrade the bore as a typical metallic snap ring would upon installation. This allows for the finish to remain in tact for sealing a gas.

Because Torlon is easily machinable, we’ve manufactured complex shapes operating in a wide temperature range as seal carriers with internal porting.

Torlon is used at higher temperatures for backup ring devices where PEEK is well beyond its Glass Transition Temp. Torlon has plenty of range to handle temperatures at or above 500+F.

Torlon is manufactured in various grades, which allows its use as a primary seal at elevated temperatures and — where bearing strength is required — may be blended with Carbon or other fillers to enhance its capability to resist strain.

Best Uses for Torlon

An excellent use for a Torlon bearing would be a drier bearing in the pulp and paper industry, allowing for a very complicated shape and resist the elevated temperatures found in the application.

Torlon is used frequently as a seal ring in transmissions due to its high strength and resistance to deformation.

It’s commonly found in automotive transmissions as a replacement for metal rings, which would score mating surfaces.

It also has excellent insulating properties for use in electrical service. Torlon can also be used as a thermal insulator for high temperature applications.

Torlon has a wide variety of uses where low-deflection and broad changes in temperature are required, while maintaining strength.

Torlon also has excellent resistance to Gamma radiation.

Eclipse has been manufacturing with Torlon for 20 years with continued success in the most arduous applications requiring high strength, chemical and thermal resistance.

Learn more about our Torlon manufacturing and application process»

Solar Power, Windmills and Water Energy: Green Energy Seals

Mon, 10 Dec 2018 17:31:00 GMT

“Green energy” or renewable energy is collected from renewable resources and replenished by the simple existence of the planet.

Some examples are energy from the sun, wind, tidal wave and geothermal heat.

The process of energy from renewable resources is the conversion of these different forms of energy into electricity. In the case of geothermal energy, it could be electricity or heat transfer for heating and cooling of a structure.

One common theme in the development of seals for green or renewable energy is that the seals have extremely low drag.

Because we typically harness small amounts of energy from these various sources, a high drag style seal can completely negate the gain of energy we are trying to harness.

Seals in Solar Panel Motors

In the case of the sun, solar-powered photovoltaic (PV) panels convert the sun’s rays into electricity by exciting electrons in silicon cells using the photons of light from the sun.

While this process doesn’t use seals per se, collecting the highest percentage of solar power is done by aiming the panels at the sun.

Tracking software allows the panels to reposition by using motors. These motors often contain environmental seals to keep the motor running smoothly throughout its life.

These seals need to have extremely low friction to allow smooth operation of the panel.
These panels may have gear boxes with gear oil.

A low-friction rotary lip seal will seal fluids in, and keep the environment out.

For direct drive high torque, low speed motors, Teflon lip seals again will retain fluids and keep the environment out of the motor and gear housings.

Seals in Windmills

Wind mills have long been a source of energy— either through direct drive, use in pumping water or grinding wheat or, in more modern times the generation of electricity with small compact generators.

In either case, seals or rope packing have been used to harness energy.

For pumping water, the pumps traditionally use a stuffing box that generally used a type of rope packing which allowed the reciprocating action of the pump to draw water from the ground. This water is often used to irrigate fields or water cattle in remote locations.

Today, windmill farms spot the countryside producing a renewable source of electric power. These giant-bladed electric generators are highly engineered with gear boxes, pitch control blades and swivel joints to keep the wind mills pointed into the wind.

Seals play an important part in keeping wind generators functional — starting with the gear box, seals ensure even a small amount of wind capable of turning the blades and producing power.

Valving within the system changes the pitch of the blades to take advantage of the wind — no matter how strong or how slight — keeping the wind generator safe from over speed.

The blades are sealed to maintain fluid in the hub of the blade to allow the blades to pitch over to maintain a constant rate.

Again, low-friction seals are required to maintain fluids in place, and allow smooth operation of the blades.

Non-metallic bearings are used for components to be operated smoothly without binding.

Seals in wind generators see extreme temperatures, and operate in hostile environments perched hundreds of feet in the air.

Teflon lip seals, rubber energized seals and spring energized seals are frequently used in combination to keep the wind generators turning at a rate that allows long life, with little need for service due.

Downtime on a wind generator requires extensive and expensive resources. Seals with long service life are essential

Seals used in Water Energy

Another form of power generation is the use of waves from the ocean.

The moon’s rotational path causes the oceans to move creating waves.

This wave action can be harnessed in the form of energy by collecting the motion of the waves moving in and out, thereby generating electric power through this motion.

These paddle-like generators rotate rhythmically with the wave thereby turning generators internally and producing electric power.

Seals could be found in these generators to keep the ocean water out and gearbox oil in.

Seals need to be impervious to seawater and be low enough friction to allow the generator to turn freely. These are typically radial lip seals with Teflon lips. Seal designs utilize multiple lips to ensure that the water stays out and gearbox oil stays in.

Seals will continue to play an important role in the generation of renewable energy with the use of low-friction materials and seal cross sections to fit the need of the application.

Most applications for renewable energy last for up to 30 years in service.

While rubber seals offer great seal-ability, they don’t have the longevity in service like a polymer style seal does. A 30-year life span is not uncommon in this industry.

Learn more about how Eclipse seals help to sustain the energy, oil and gas industries >

The Role of Rising Stem Valves in the Oil and Gas Industry

Wed, 28 Nov 2018 20:14:00 GMT

The oil and gas industry poses some of the most challenging seal applications for any seal designer.

This is largely due to the varying chemical compatibility of fluids, and extremely high temperatures.

The fluids often contain solids, which tend to be extremely abrasive. And applications are usually at high rotary speeds with extreme pressures.

This combination creates PV values (pressure x velocity) often reaching the limits of the seal materials.

On top of these extremes, as seal designers we are also faced with containing fugitive emissions from valves and rotary equipment, in a very hostile environment like the oil field.

That’s where the rising stem valve has provided numerous solutions in the oil and gas industry.

The rising stem valve is an area that has seen a large development in the transition of seals over the years.

Early seals were packing or rope packing which evolved into special grades of rope packing.

Many older style valves continue to use this type, but require a tightening of the packing nut till, and an acceptable amount of leakage and friction were acquired.

“V” packings have been used as drop in replacements for rope packing, which still utilizes the packing nut to energize the seal. This style was better able to control leakage, while reducing friction.

A variety of different ring materials were used to curb the leakage, including Perfluoroelastomers to handle the various chemicals and rising temperatures.

The need to prevent fugitive emissions also forced the oil and gas industry to consider a wider variety of ring materials and loading. These improvements enabled better control of the released gases.

Spring energized seals gave way to better leakage control and lower friction. However, the condition of the packing gland often would not allow for this style of seal to perform.

The spring energized seal needed a good clean sealing surface. It allowed for long use with no adjustment as no packing nut was required. This style of seal also could control fugitive emissions if the hardware was in good condition.

Due to extreme pressures and temperatures, these spring energized seals needed to have very thick cross sections so that they would not extrude under the rigors of the application which forced the seal designer to include a series of springs or multiple spring packs to help energize the Teflon lips .

And while the Teflon type materials could easily handle the pressures and temperatures, the springs needed to be made of materials impervious to chemicals like Hydro-sulfuric acids or H2S.

As seal designers, we turned to materials like Hastelloy and Elgiloy, which provided superior chemical resistance even in these chemically harsh environments.

Once a cross section on a clean surface was established, the spring energized lip seal was capable of handling liquids and suspended solids and gas — While at the same time handling strict federal regulations for fugitive emissions.

We were then able to do away with packing glands that required continuous monitoring for leakage and adjustment of the packing nut.

We were also able to provide a sealing package that maintained a constant predictable friction, so activation with motor drives would be possible for remote activation of the valve.

With the use of different fillers in the Teflon and a combination of back up ring devices , this style of seal was made to support even higher pressures and temperatures.

The oil and gas industry has long been a user of materials like PEEK with glass transition temperatures in the high 400F range. While this has become somewhat of a standard, materials like Torlon and Polyimide allow the designer to reach even higher temperatures.

With the use of high modulus materials such as Torlon or Polyimide, temperatures could exceed 600F and climb into the 800F or higher. This was due in part to the very high glass transition temperature of these materials.

The rising stem valve seal is a very small portion of the oil and gas industry, but one very visible due to the stringent leakage requirements. We continue to see new and interesting opportunities to increase the sealing capability by use of some of these higher modulus materials.

Spring energized seals have found a home in this rigorous application. Learn more about the various applications for spring energized seals »

Choosing the Best Seal Type for Industrial Applications

Tue, 13 Nov 2018 19:05:00 GMT

The Industrial seal market is by far the broadest and most encompassing of all seal markets. This industry uses seals that need to function with every fluid imaginable, temperature ranges from absolute zero to over 1000 °F, and pressures exceeding 100k PSI.

Industrial seals also include rotary seals that can see a vacuum to PV’s (pressure-velocity) that can often exceed 500K-PV.

Solving our industrial seal customers’ problems requires our seal designer to understand how the equipment will operate. This allows us to visualize the duty cycle.

Understanding the overall need for the level of seal-ability, friction and life, points us to a style of seal, material and — with known volumes to produce — the type of manufacturing process we’ll need to consider, as cost is always a factor.

Other factors to consider are how we’ll replace these seals in the field, as opposed to and OEM factory installation.

Choosing the Right Industrial Seal

When we classify industrial seals, we normally assume that the product may be used in the manufacturing of a commodity product — but normally not in the commodity itself.

This implies that service up-time and ease of replacement are very import in the development process. You don’t want your seal to be the one item shutting down a production line, or stopping the work of a back hoe while building a structure.

For most industrial applications, an O-Ring provides an excellent seal. But O-Rings are limited in their uses such as temperature, fluid compatibility, and friction.

And while O-rings may be the lowest-cost product, they may require frequent replacement if not applied properly in these applications.

Going back to pressure and friction, rubber-energized polymeric or Teflon-style seals often combine strong resistance to pressures in excess of 1500 psi, and friction 10-20 times lower.

This style of seal combines the gland backside leakage control of an O-Ring with the excellent seal and friction qualities of a filled PTFE (Teflon®) . Life is normally greatly enhanced, while giving up a slight amount of leakage control.

Controlling Leakage in Industrial Seals

Understanding the overall system requirements allows our designers to determine the level of seal-ability, and choose a seal system that provides leakage control to zero — while still improving life, reducing friction, and handling extremely high pressures.

However, these features do come at a cost. And in industrial style applications where up time and service-ability are paramount, the overall cost of the correct product normally outweighs the downtime of seal replacement in a product not suited for the application.

Fluid compatibility or a variety of fluids which create havoc with an elastomer are easily managed with the use of spring energized seals .

When considered in the design process and with proper gland consideration, these seals can often be easy to install and may be extremely robust, while sealing out a variety of chemicals and solids (like paint or concrete).

Spring energized seals are also capable of handling acids, bases, and a combination, including a variety of solvents.

Elastomers often suffer as the end user may use a variety of solvents that aren’t always compatible with the elastomer chosen.

Friction is extremely repeatable in “dialing in” a spring energized seal for uses in medical equipment where touch is so important. This could include the threading of a catheter or a robotic arm setting an IC chip in a board.

Oil and Gas Seals

Seals used in oil and gas are a subset of industrial seals. Spring energized seals can be made to preform in extreme service including contaminants, pressure and fluid variation such as sour gas and oil.

Rotary Seals

The rotary seal market is another area where seals find their mark. O-Rings and quad rings find themselves handling light duty rotary service. And when speeds increase, we often choose a rubber lip seal, encased in a metal case and pressed into a gland.

Most rotary applications, such as automotive , often rely heavily on the rubber lip seal. This seal is ideal where the environment is very well defined, relatively benign with low pressures (less than a couple of PSI), and extremely cost effective.

But the industrial-style rotary lip seal often sees pressures over 10 PSI, and as high as 500PSI. It’s common to turn to cased Teflon lip seals to handle pressures and speeds with PV’s exceeding several 100K.

The rubber lip seal suffers when the pressures exceed 10 PSI with any speed due to the high drag and friction of rubber against a shaft. Teflon lip seals can be loaded, unloaded, or have spring energized profiles that allow us to control friction and leakage, with speeds and pressures driving PV’s to 250K or above.

These cased seals can have cross-sections as small as 1/8 inch working in a variety of fluids.

With state of the art design technology and materials, Eclipse Engineering has the capability to design, deliver, and support all your sealing needs. Learn more about our projects and capabilities in the industrial seal industry >

Improving the Semiconductor Industry With Ultra-Pure Seals

Fri, 26 Oct 2018 17:02:00 GMT

The semiconductor industry is a specialty market that requires seals to work in extreme chemical and temperature environments.

Seals in the semiconductor industry must block seal materials from entering the fluid stream.

There are several different ways for seals to accomplish this task, but the first consideration is the operating characteristics.

Operating Characteristics of Seals for the Semiconductor Industry

For static seals where no relative motion exists, the use of perfluoro-elastomers, or FFKM rubber, is considered a first consideration.

DuPont offers molded O-rings and custom seals using a series of specialty products and ultrapure processing for the semiconductor industry.

Ultrapure processing is standard for all semiconductor product grades and must be specified for Kalrez 6375UP and 7075UP.

Kalrez is a widely accepted choice as a supplier of Ultrapure compounds in the semiconductor industry and can be supplied by Eclipse.

The Role of PTFE in Semiconductor Seals

For dynamic seal applications where a consideration is wear and friction in these same operating conditions, Eclipse designs and manufactures spring and rubber energized seals made from materials such as Polytetrafluoroethylene PTFE , (Teflon®) or Ultra High Molecular Weight Polyethylene.

These seals are typically machined cross sections, and are energized by metallic springs or rubber elastomers.

PTFE is essentially inert to almost any chemical, and a metal spring can be selected from the accepted metals used in other areas of the equipment — typically a 300 series spring steel.

If the seal is rubber energized, the use of a Perfluoroelastomer such as Kalrez may be used for its excellent chemical and temperature compatibility.

These materials are not limited to round shapes. They can be machined into virtually any profile to accommodate the application.

Specialty Design Elements for Semiconductor Seals

When pressures exceed the mechanical strength of these standard polymers, Eclipse can build backup ring combinations to handle pressures in excess of 100K PSI.

When pressures go negative or vacuum, Eclipse is capable of building sealing systems that are capable of sealing to extreme vacuum, and continue to function as dynamic seals.

This is accomplished with our super finish process for polymers, in combination with the application hardware and finishing of the mating surface for the dynamic application.

For boundary seals for electronic enclosures, Eclipse can design seals or protection devices to keep the outside environment out and retain fluids from getting out of the electronic device.

Eclipse has designed both Polymer enclosure seals that operate in severe glove box or electronic enclosures to insure product within the enclosure stays there, and the outside environment stays out.

When designing with the harshest of chemicals and operating at temperatures that can swing from -400 degrees Fahrenheit to an excess of 500 degrees, the use of a polymers such as PTFE and elastomeric materials such as FFKM (Kalrez) provide for long term solutions that will keep your production equipment up and running longer and your PM cycles to a minimum. This reduces overall downtime, improving run time and making your operation more profitable.

Eclipse has been in the seal business for over 20 years, supplying the world with sealing solutions used under, on and off our planet, operating in the harshest environments such as the semiconductor industry.

Learn more about how Eclipse’s seals serve the semi-conductor industry >

The Best Applications for High Modulus Plastic Materials

Tue, 23 Oct 2018 17:27:00 GMT

High Modulus plastics such as Polyetheretherketone ( PEEK ), Polyamide-imide (PAI), Torlon® Polyimide (PI) or Vespel® are all tough, rigid polymers suited to work in various chemicals and temperatures. And with the right fillers, these plastics can act as seals, bearings or machined profiles.

When designing seals using materials such as PEEK , special consideration regarding flexibility and seal design must be taken into consideration.

Materials like PEEK are often used in sealing applications in Gamma radiation environments, as PEEK provides good radiation resistance along with temperatures up to 500F.

Certain high-pressure situations don’t always have the right amount of space to allow for a Backup Ring . In this case, the higher modulus properties of PEEK are often used.

These higher modulus polymers are often used in very high pressures (in excess of 10,000 PSI) with elevated temperatures.

Superior Qualities of High Modulus Plastic Materials

High Modulus materials like PEEK or Torlon lend themselves to shapes that can be held to very tight tolerances and various profiles that don’t need to be round.

Split piston rings with milled faces that allow the ends to overlap and create a seal are available in various sizes. As another example, high modulus plastics can be used for retention snap rings in applications where metal to metal contact might damage sealing surfaces during installation.

Machined snap rings where retention is required but metal to metal contact of a snap ring could damage a sealing surface during installation is another example.

PAI or Torlon® is a consideration when temperatures exceed 500 F. PAI has been used under the hood as a direct replacement for many metal components on cars. And when temperatures exceed 700F, PI or polyimides are available to fill the Polymer gap with temperature with excursions up to 900 degrees Fahrenheit.

Eclipse has been machining from all these materials into a variety of housings that allow valves to operate smoothly in very harsh chemical environments.

Very small (O.D. under .050) pins used in medical instrumentation, and specialty seals in excess of 16 inches where special porting through the seal with notches, holes, angle cuts or split rings used in Natural Gas transmission lines, are machined to tolerances of +/-.002 even up to 15 inches in diameter.

Some of these materials are FDA compliant, and will normally handle very broad temperature swings. They’re also extremely light weight in comparison to their metallic counterparts.

These materials normally include fillers that improve physical properties allowing for even higher stresses, extending their useful load carrying capability when faced with higher loads.

As polymers, they’re easily machined so intricate shapes at extremely small diameters are possible. They often machine similar to steel so installing grooves for snap rings to hold seals allows entire rod ends to be machined from polymers.

These materials can be threaded for locking purposes, and notches installed for indexing into hardware if required.

Designing with Polymers

When designing with polymers, we normally start with materials like Acetal (Delrin®) or Nylon, and review the environment the materials will be working in.

Conditions that will drive the use of PEEK, Torlon, or Vespel over some of these common materials are, temperature, chemical resistance, radiation resistance, friction, and strength of the material.

When utilizing these polymers, cost is always an important factor. Plus, the need for small lot production vs. high volume and the complexity of the shape or seal may dictate the type of material applied.

Can the polymer be injection molded, or does it need to be compression molded? Each of these different processes change the overall physical properties of the parent material.

Friction in dynamic applications can also be a major factor in material selection. Some materials accept fillers easier than others and the consideration of these fillers directly impacts physical properties like friction and strength of material.

Availability generally plays more of a role in the development phase as parts are typically machined vs paying for tooling for a trial mold.

There can be a question regarding the performance of the way the raw materials are processed for machining vs the same part compression or injection molded. For example, the ductility of the material can be affected by these different processes.

High Temperature Materials

To this point we’ve limited our discussion to materials that top out at 900 F. But what’s the next step for materials reaching 1500 degrees Fahrenheit?

Carbon and Ceramics while not nearly as friendly to work with as polymers, are available for extended service above 1000 degrees Fahrenheit.

Some complex shapes can be machined, but not with nearly the flexibility we have with polymers. Carbon is typically used for faces in mechanical face seals.

Ceramic is often seen as a seal and valve guide, and while not nearly as tight a seal, can be held to tight tolerances limiting the leakage in a labyrinth situation, while also providing guidance on a moving valve.

The world of High Modulus polymers offers the designer a wide variety of choices in dealing with conditions or shapes that are not as friendly or cost effective for metallic housings or seals.

Best Uses of 3 Energized Spring Types

Thu, 04 Oct 2018 15:00:00 GMT

When looking into an energized seal for your needs, there are 3 configurations of spring to consider: Cantilever “V” Springs, Helical Wound Springs, and Canted Coil Seals.

Each spring type has a unique advantage depending on a certain set of conditions. Below are the advantages of each energized spring type and their ideal use.

Why do I Need an Energized Seal?

The primary reason to consider a metal spring energizer is to overcome the limitations of the polymer seal jacket.

Polymers offer the compliancy necessary to create a seal, but in order to maintain sealing over a broad range of application parameters, a method of consistent loading is required.

Eclipse spring energizers fulfill these requirements by providing energy to overcome varying temperatures, pressures and hardware tolerances.

Benefits of Cantilever “V” Springs

A Cantilever “V” Springs is a commonly specified spring type. This “V” shaped spring offers very predictable loading, which makes it great for general use.

With a linear load curve and excellent deflection range, Eclipse Cantilever Springs are a highly versatile product.

The shape of the spring concentrates load on the front of the seal, which makes this design suitable for use as environmental excluders and for applications requiring scraping of viscous media.

As an additional option, the spring cavity area can be filled with silicone for FDA clean-in-place applications

Best Applications

Benefits of Helical Wound Springs

Helical springs are constructed of wire ribbon wound into a circular helical shape.

This helical shape spring affords a relatively high load versus deflection range resulting in a seal product that can provide very tight sealing.

As a highly loaded product, Helical Spring Seals should be considered when dynamics are very slow or static.

Best Applications

Benefits of Canted Coil Seal

Canted coil springs are constructed from spring wire, formed into a circular and canted shape.

The canted coil is unique in the sealing industry because of its broad, consistent loading curve.

As an engineered loading device, canted coil springs display a very constant load over a large deflection range.

This feature allows Canted Coil Spring Seals to operate in friction sensitive applications.

We stocks several sizes, materials and loads to optimize the seal for the application.

Best Applications

These Eclipse spring types offer the designer a product to address any application concern. Contact us to discuss the optimum energized seal solution for your project >

Designing Seals for Extreme Temperature Limits

Thu, 20 Sep 2018 15:00:00 GMT

The temperature limits of a seal can make or break the functionality of important machinery. And there’s maybe no example of this more palpable than the disastrous explosion of the Challenger, just 73 seconds into its flight.

The initial cause of failure was a Fluorocarbon O-ring that could not accommodate the cold temperature swing, along with the expansion of the O-ring joint. This combination allowed hot air gases to escape, burning a hole in the Hydrogen/Oxygen tank affixed to shuttle.

Although there are many factors behind the disaster, the temperature limit of the O-ring in the shuttle played a major role.

The Role of Temperature Limits in Seal Design

When we design product for sealing applications, there are a key few elements that drive the final design of the product: pressure, geometry of hardware, fluid compatibility, economics and, of course, temperature.

In benign environments, between 32 °F to 180 °F, most materials including rubber will normally survive and work well within the operating parameters.

But with many sealing applications, we see high temperatures over 400 and as high as 750 °F, or going in the opposite direction liquid oxygen sits around -300 °F. And if you wanted to make the molecules stop moving, you’ll need to get to near absolute zero or around -465 °F.

These extremes cause the designers at Eclipse to select the right materials for sealing, along with seal cross sections that will withstand these extremes.

When designing seals, we look at all the properties that affect seal ability.

Focusing on temperature often dictates the types of materials we’ll use. For example, we’ll use PCTFE to operate at -460°F or a Polyimide for temperatures in excess of 600°F.

If the range is narrow enough, we can utilize elastomers like specially compounded Nitriles which can go from -65 to 275 F. But we must develop sealing systems that accommodate these temperature spreads.

Sealing Systems to Accommodate Extreme Temperatures

We often turn to spring energized seals to cover the gaps, especially when our range exceeds what elastomers can handle.

This allows us to be mindful of the types of springs and the alloys we use to allow the spring to give us the physical properties necessary to accomplish sealing.

The use of back-up ring systems in conjunction with seals — be it rubber-energized or spring-energized — allow us to cover gland geometry and extrusion gaps, which are again highly dependent on the temperature range we’re trying to span.

With large temperature swings, we need to allow the seals to follow a non-standard bore material, like Nylon, which could grow to the point that our seals won’t follow.

Using rubber or metallic springs allows us to compensate for a wide range of changing diameter due to changes in temperature.

When temperatures exceed 750°F, we consider the use of carbon seals energized by steel bands to handle temperatures over 1200°F.

While our goal may not be to make a perfect seal, the rigors of working at these elevated temperatures causes the seal designer to help establish what the hardware will ultimately look like.

Sealing using materials around their glass transition temperatures requires care to ensure the seal will return to a state usable for future temperature excursions.

Similarly, seals used to protect against leakage during a fire require that the seal fails in such a way as to not leak causing further damage due to the fluid being an accelerant.

One of the fundamental requirements in rotary sealing is for the seal material to stay within a specified PV (Pressure-Velocity) limit.

But our formulas don’t take into consideration temperature, which directly relates to the survivability of a seal. In manufacturing rotary seals, there is a strong need to reject heat and continue to seal as the material softens due to the increased temperatures.

Similarly, some materials are not suited for temperature excursions in rotary service such as UHMW , however UHMW does an excellent job in sealing water. So if the temperature continues to be low, or stays low due to the product flowing through the system, UHMW might be the best material.

While many applications may be well-suited for a simple O-ring , when factors like temperature come into play, this causes the designer to consider the impact of the environment.

In combination with pressure and fluids, temperature could be the major factor in the design of a seal. And one of the industries that relies heavily on seals that can withstand extreme temperatures is the aerospace industry.

Discover how Eclipse Seals supports the aerospace industry >

Which Spring Energized Seal is Best for My Application?

Fri, 24 Aug 2018 15:00:00 GMT

Spring energized seals are found in a wide variety of equipment where O-rings or rubber energized seals are not capable of handling the environment.

These environments include a wide temperature range, fluid compatibility or low friction requirements.

Spring energized seals generally require more care and consideration compared to other type seals, but give a wide advantage in performance.

Here are 7 common types of spring energized seals and their ideal applications.

Cantilever Spring Seal

Cantilever Spring Seals make use of a V-shaped spring installed in a polymer jacket.

At installation, the V shape of the spring is compressed, providing sealing energy to the seal jacket ensuring a positive seal.

With a linear load curve and excellent deflection range, Eclipse Cantilever Spring Seals are a very versatile product.

They are common replacements when rubber u-cups fail due to chemical attack, extreme temperature range, friction concerns and wear issues.

Best applications for Cantilever Spring Seals

Cantilever Spring Seals are best suited for reciprocating applications such as shocks, hydraulic cylinders, pumps and compressors.

The shape of the spring concentrates load on the front of the seal, which makes this design also suitable for use as environmental excluders and for applications requiring scraping of viscous media.

As an additional option, the spring cavity area can be filled with silicone for FDA clean-in-place applications.

Canted Coil Spring Seal

Canted Coil Spring Seals employ a specialty wound wire spring installed in a polymer jacket.

The canted coil is unique in the sealing industry because of its semi-linear load curve.

Best applications for Canted Coil Spring Seals

As an engineered loading device, canted coil springs display a very constant load over a large deflection range.

This feature allows Canted Coil Spring Seals to operate in friction sensitive applications like HPLC, encoders and flap actuators with consistent performance.

Seals used in battery operated devices utilize these seals to minimize seal friction and optimizing battery life.

On the other end of the spectrum, Canted Coil Spring Seals are used with heavy load springs for use in highly viscous media such as epoxies and urethanes.

Eclipse maintains an extensive inventory of canted coil spring making it possible to tailor seal requirements to nearly any application.

Helical Spring Seal

Helical Spring Seals are comprised of a wound ribbon metal spring installed in a polymer jacket.

This helical shape spring affords a relatively high load versus deflection range resulting in a seal product that can provide very tight sealing.

Best applications for Helical Spring Seals

As a highly-loaded product, Helical Spring Seals should be considered when dynamics are very slow or static.

Examples are in stems seals and in cryogenic valves where additional force is required to overcome thermal effects.

Extended Heel Spring Energized Seal

Extending the heal on a spring energized seal is generally done to allow for higher pressures or temperatures.

The heel extension provides better support for the seal against extrusion.

If pressures and temperatures become very high, a separate back up ring device is often incorporated in the seal system.

Best applications for Extended Heel Spring Energized Seals

Systems with pressures in excess of 3000 PSI or 275 degrees F will often see extended heels.

High pressure fuel systems for aircraft engines, which can see a combination of heat and pressure will often have an extended heel.

Materials will vary depending on the application and hardware, but generally we use a filled PTFE compound for high temperature and chemical resistance.

Flanged Seal

Flanged seals are a special class of radial seals with an added feature to help retain the seal under rotary forces.

The flange is an extension of the heel of the seal, which locates in a counterbore of the housing.

At assembly, the seal flange gets pinched in the housing providing a positive mechanical lock that keeps the seal stationary.

Best applications for Flanged Seals

Flanged seals are an excellent choice for equipment that can be designed with end plates.

In these cases, assembly of a flanged seal is simple and provides a robust design as well as a level of redundant sealing on the static side of the gland.

Process machinery that require a product to be contained (mixers, augers, spool valves) are good applications of this design.

O-Ring Heel Seal

When considering a rotary service seal and additional gland length is available, an O-Ring Heel Seal provides a level of anti-rotation and redundant sealing.

The addition of an O-Ring on the heel of a radial seal creates a high friction interface at the bore to counteract rotary forces.

Best applications for O-Ring Heel Seals

With proper hardware design, a high level of sealing can be realized, making an O-Ring Heel Seal a good choice where gaseous or low viscosity fluids need to be sealed.

O-Ring OD Seal

When considering a rotary service seal and additional gland diameter is available, an O-Ring OD Seal provides a level of anti-rotation and redundant sealing.

The addition of an O-Ring on the OD of a radial seal creates a high friction interface at the bore to counteract rotary forces.

Best applications for O-Ring OD Seals

Because the O-Ring is a lower durometer than the jacket material, it is more compliant and offers tight sealing on the bore.

This feature is utilized in equipment such as vapor recovery and vacuum pumps where running friction needs to be low and sealing efficiency high.

Cased Spring Seal

Cased Spring Seals are the best option for extreme rotary service.

In these designs, a metal case is constructed around the outside of a spring seal, which in turn gets press-fit into the hardware bore.

A metal-to-metal press-fit ensures a tight seal as well as a highly effective anti-rotation mechanism.

Best applications for Cased Spring Seals

Because these seals are installed into open bores, they lend themselves to rotary applications such as gearboxes and power transmission systems.

They can also be utilized as rod end scrapers, where exclusion of aggressive media is desired. These seals are capable of pressures similar to an extended heel seal.

In all rotary seals, the PV limits of the material must be considered.

Face Spring Seals

Face seals are for non-dynamic applications and with seal pressure inside a vessel (Internal Face Seal) or keep media out of a vessel (External Face Seal).

Some face seals do operate dynamically, but consultation with the factory is highly recommended if a dynamic face seal is required.

Best applications for Internal Face Seals

Internal Face Seals are commonly installed in pressure vessel cover plates and in pipe flange assemblies.

External Face Seals are often used in vacuum chambers and as excluders to keep debris out of thrust washer areas.

Backup rings are another common mechanism which are designed and manufactured by Eclipse. Discover 3 common types of backup rings and their applications >

Seals You Use Everyday

Mon, 13 Aug 2018 15:00:00 GMT

Seals are the great unseen player that keep the mechanisms we use every day working properly.

From making breakfast in the morning to driving your job to tending your garden in the evening, we all interact with seals from sun up to sun down.

The bottom line is, seals help to keep certain things in, and to keep other things out.

Here are the seals most of us use in our everyday lives and the role they play in our kitchens, gardens, automobiles and more.

Seals in Your Kitchen

Ready to pop a pie in the oven? Then you’re about to encounter a seal.

Your oven has a rubber seal around the door to keep the heat in, while allowing you to open and close the door.

Once the door is closed, the seal on the door allows you to keep your food piping hot with an air-tight container, aka a sealing lid.

Seals in Your Garden

There’s nothing like growing fresh veggies in your own backyard. And seals help you make sure your garden thrives all summer long.

Your water spray gun connects to your hose fitting with a rubber seal. This seal helps your hose maintain water pressure and prevent leaking, so you can control the water flow to your garden.

Seals in Your Car

You can thank seals for your car’s ability to keep you dry while driving through a rain storm.

The doors all have a molded rubber seal around them to keep the rain out, while still allowing you to get in and out whenever you need to.

Seals in an Airplane

Seals are a critical component in todays modern aircraft. They can be found in flight controls, landing gear, engine fuel systems and aircraft pressurization, just to name a few.

Seals in flight controls will allow a Boeing aircraft the ability to take off, control all aspects of flight, land and brake without human input.

Seals at a Restaurant

When you go out for lunch, seals play a big role in your dining experience — from the table where you’re seated to how your food is made and processed.

Seals are used in processing and storing food. They’re also used in the mixers that fold dough for the bread on your table.

And if you top off your meal with a local micro-brew, seals are used in making sure your beer is dispensed with a great head and chilled to just the right temperature.

Seals at the Hospital

Without seals, you wouldn’t be able to receive the critical treatment you need during a hospital visit.

Seals are used in medical equipment to ensure fluids are retained, and that contamination is kept out of operating systems.

Seals also help keep electrical components dry and preforming at their peak. A few examples of seals found in medical equipment include:

Eclipse has designed many different seals to fit the needs of medical equipment manufacturers. Learn more about how Eclipse seals have revolutionized the medical equipment industry >

3 Common Types of Backup Rings and Their Uses

Fri, 27 Jul 2018 20:45:00 GMT

The Backup ring likely found its roots in the use of leather packings, where leather was used as the sealing device in glands prior to the use of O-Rings .

The O-ring provided a much better seal compared to leather. However, the leather often filled the extrusion gap allowing for larger gaps.

The persistent problem that engineers faced was how to take an O-ring that operated optimally in close extrusion gaps, and extend its service with widening extrusion gaps.

The answer was the Backup ring .

The first Backup ring devices were made from materials like leather.

Leather did two things to help the O-Ring: it filled the gap, and continued to lubricate the O-Ring during dry running conditions. You can still occasionally find some old style hydraulic systems using leather back-up rings.

Modern Construction of the Backup Ring

Our modern hydraulic systems often find O-rings operating at extreme pressures, with the use of Backup rings made from a variety of materials like Teflon® or filled PTFE materials .

Polyester Elastomers like Hytrel®, Nylon , PEEK , and other high modulus materials that are compatible both in pressure and temperature to the application.

These Backup ring devices can take on many forms such as solid rings, split rings and spiral wound Backup rings.

Where there are extreme pressures and high temperatures you may find cammed Backup rings with varying materials to protect the O-ring, while at the same time closing the extrusion gap allowing extreme pressures in excess of 100 KPSI (690 KPA).

3 Common Backup Ring Shapes

There are 3 basic standard shapes for Backup rings: Solid Backup Rings, Spiral Wound Backup Rings and Scarf Cut Backup Rings.

Solid Backup Ring

The Solid Backup ring which, when made of an appropriate material can be forced into solid rod glands, but must be stretched to go into piston glands.

Face seals often find solid Backup rings due to the ease of installation.

Scarf Cut Backup Ring

The Scarf Cut Backup ring is probably the most commonly used Backup ring in today’s modern hydraulic system.

It’s easy to install in solid glands, whether they’re rod or piston. And because it’s split, the Scarf Cut Backup ring can be made of very hard materials to handle extreme pressures.

A note of caution with very high modulus materials: the split can cause nibbling of the O-Ring allowing for premature failure of the sealing system.

In the event of the need for these higher modulus materials, a softer ring may be placed between the O-Ring and the high modulus ring to protect the O-ring from this nibbling.

When applied properly, the Split Backup ring can open or spread to completely fill the extrusion gap when under pressure — something the Solid ring is unable to do.

Spiral Wound Backup Ring

The third Backup ring type is the Spiral Wound.

Modern systems rarely use this type of Backup ring due to the cost and availability. The Spiral Wound Backup ring isn’t commonly found on the shelf, but is occasionally employed for specific purposes.

There are many variations on Spiral Wound Backup ring, device such as the Par-Bak® or Cam-bak, which each serve a more specialized need.

Common Uses of Backup Rings.

The necessity of a backup ring is dependent on the extrusion gap, pressure, and temperature of the system.

Most O-rings from the zero series through the 400 series will survive with gaps ranging from .002 to .007 diametrical.

A typical O-ring will perform within the range of extrusion gap, and series up to 1500 PSI (10 MPA).

An extrusion gap allows for manufacturing to put together a system. Generally, the larger the diameter, the larger the extrusion gap.

Tight tolerance cylinders can be difficult to assemble, especially if you’re trying to maintain very small E-gaps.

Backup rings allow for ease in manufacturing to assemble without the fear of damaging rods or bores during the installation process do to overly tight E-gaps.

Cylinders and valve bodies often use O-Rings as static seals. Pressures exceeding 1500 psi and extrusion gaps exceeding the recommended maximum will require some form of back up ring device.

The shape and material will depend on the pressures and temperatures that the system is operating.

In piston style glands where pressure can be seen from both sides of the O-Ring, it’s common to use two Backup rings to support the O-ring in the extrusion gap from both sides of the O-Ring gland.

Static Face Seals often require Backup rings to support O-rings from entering the extrusion gap.

In extreme pressure cycles a known extrusion gap can be enlarged due to the gland bowing or moving into the extrusion gap.

Under extreme pressures, a Cam-style backup ring Is often used to drive a high modulus material into the ever-expanding extrusion gap closing the gap to zero and allowing the rubber O-ring to fill the void without entering the extrusion gap.

Discover how Eclipse designs glands to avoid O-ring extrusions >

How the US Tariff on Teflon May Affect the Industries That Use It

Wed, 18 Jul 2018 20:44:00 GMT

A new tariff on polytetrafluoroethylene (more commonly known as PTFE, or Teflon) from China and India is shaking up the Teflon market and the industries who use it.

From cookware and surgery to aerospace and automobiles, PTFE is used in many ways on our daily lives.

This tariff could even affect Eclipse Engineering, as we use PTFE to solve problems on a daily basis.

What is PTFE?

The most common trademarked product made from PTFE is Teflon.

Teflon is a synthetic material that is recognized for its durability and ability to function in a wide range of temperatures ( -450F to 575F ).

Teflon is commonly called upon for its low-friction properties and its inertness , which makes it compatible for use with most chemical compounds.

Because of its diversity of attractive properties, PTFE is in high demand across the world. The global market for PTFE, in fact, is expected to reach $2.9 billion by the year 2022 .

Common Applications for PTFE

Non-stick Coating

One of the most common uses for PTFE can be found in the kitchen. Teflon is the main component of non-stick coating for pots and pans.

Seals

PTFE’s low-friction properties in combination with its chemical inertness also make it a go-to for seals used in equipment — especially in rotary power applications.

Think gear pumps, compressors, and generators. Eclipse often turns to PTFE seals for these applications.

Medical Equipment

Another important use of PTFE is in surgical equipment.

Its non-stick properties are perfect for surgical tools and packaging . And when combined with a non-acid formula, it prevents bacteria from growing on surfaces, keeping them sterile.

Other Uses

There are still more applications of PTFE:

What Does the PTFE Tariff Do?

The new tariff is essentially a tax or duty that Chinese and Indian producers of PTFE pay when exporting the material to America.

The current administration says the tariff is in place because it believes that the foreign product is currently underpriced.

With almost $24.6 million in PTFE exports to the US from China alone , plus another $14.3 million from India , the tariff is expected to have an impact on the American economy.

What Effects Will the Tariff Have?

The answer to this question isn’t clear.

The US Commerce Dept. is currently making preliminary determinations about the tariff based on its effects.

It’s scheduled to make final decisions about the tariff this fall.

In terms of immediate effects, the prices on PTFE have risen and are now sitting at a 4-year high . We won’t know how much the tariff might affect the price of products that use PTFE until next year.

Whether or not consumers will feel the impact of this price change depends on if companies that make products with PTFE can find cost-savings elsewhere . It will also depend on wither manufactures can find alternatives at cheaper prices from places other than China or India.

PTFE is too valuable to be rendered obsolete because of price fluctuations. Immeasurable products that enhance our daily lives rely on PTFE.

Regardless of the impact of the tariff, Eclipse Engineering will continue to deliver the most accessible and affordable PTFE options to our clients.

Read about a specific client problem that Eclipse helped fix with a creative PTFE solution >

How Eclipse Seals Revolutionize the Medical Equipment Industry

Fri, 13 Jul 2018 14:34:00 GMT

During an operation or a procedure, medical equipment must have a nearly 100% reliability rate to be considered a viable tool to work on a patient.

Seals play a very important role in many different facets of medical equipment operation.

They ensure that fluids are retained, and that contamination is kept out of operating systems. Seals also help keep electrical components dry and preforming at their peak.

There is a variety of equipment that use seals in the medical field. A few examples of this equipment includes the following:

Here’s an in-depth look at how seals help ensure the optimal performance of a variety of medical equipment.

Seal Components Found Within Medical Equipment

Disposable Catheters

Catheters are often used during a surgery or medical procedure to allow access into arteries or veins. Catheters serve many different internal procedures, including an atherectomy.

Sealing around the inserted instrument allows fluids to pass through the tube, or be blocked from exiting the body.

In some cases, the catheter is rotated during the procedure. This requires very low friction seals.

Some of these applications utilize small motors that require very low friction, so that the motor does not stall, and contamination is kept out of the motor.

Prosthetic Feet

In prosthetic feet, seals are used when fluids within a chamber allow a patient to adjust the angle of their gate.

This adjustment is based on the type of footwear being used. These types of seals need to be able to handle pressures that can exceed 4000 PSI.

Accumulator in Prosthetic Knees

Artificial knees can create a gate problem for the patient if the leg isn’t allowed to swing freely as the patient walks

By use of a small accumulator with oil and a gas in the device, a patient has a more natural gate as they walk.

Saline Pumps

Medical pumps commonly use seals for functions like pumping fluids into the body — including saline.

The seals must meet FDA compliance, and be capable of being sterilized or gamma irradiated without breaking down between cleaning cycles.

Respirator Pumps

Respirators are used to help a medical patient breathe when their lung action has been compromised.

These seals are typically over 5 inches in diameter, and often seal on non-metallic bores.

The seals must meet FDA compliance, and have very little drag. In the event of a power failure, friction caused by a seal will be a major power drain on the system. This friction will use up limited battery operation.

Suction Pumps

Suction pumps are found in numerous medical applications for drawing fluids from open or closed bodily cavities.

These suction pumps are used in central vacuum systems within institutions, or individual off-site pumps.

For off-site use, these pumps must be relatively quiet, and still produce enough suction to clear cavities or airways.

Seals are again a major contributor for energy use, so seal friction must be minimal to allow for optimal suction pump performance with limited battery life.

Saws and Drills

Saws and drills are commonly used in the operating room to aid the surgeon in a procedure.

Drills commonly have electric motors that are continuously being exposed to fluids.

Drills and saws must be able to seal out liquids, and endure a thorough cleaned via steam or irradiation.

Seals are necessary to keep electrical components dry and preforming at their peak.

Saws are also electrically driven. These components also require seals that will keep fluids from entering the electrical components — both during the procedure and when the tool is being cleaned and sterilized.

Eclipse’s Experience in Medical Equipment Seals

When a patient loses a limb, they often turn to a prosthetic limb that includes a device that would mimic a foot.

Every patient typically has a variety of different shoes. Because shoes are cut differently, the artificial foot needs to be able to rotate in a way that allows for proper orientation of the foot to the ground.

With a properly-designed valve mechanism within the prosthetic foot, the angle of the foot within the shoe may be modified to give correct orientation of the foot to the ground.

This valving may allow for absorption of shock for the user.

Through a series of valving, Eclipse has designed a series of spring energized seals that allow medical patients to unlock the valve within their prosthetic foot.

This system works by depressing a cylinder on the valve block and repositioning the angle. The valve is then relocked by depressing another button on the valve block.

Other devices may contain a small amount of gas as a shock absorber to allow a more natural gate. In this instance, a spring energized seal can be used to retain fluid and keep the gases locked in the valve body.

The design staff at Eclipse Engineering is ready to assist in your design of medical equipment and devices for use in medical care. Call us today to learn more about Eclipse Seal’s medical equipment capabilities >

The Advantages and Disadvantages of PTFE O-Rings

Tue, 22 May 2018 21:53:00 GMT

While most common O-Ring materials are rubber or elastomeric compounds, certain operating conditions and hardware configurations merit the use of PTFE as the material.

PTFE offers many distinct advantages over elastomers. These advantages include corrosion resistance, massive temperature range capabilities, excellent electrical properties and an almost unlimited shelf life, to name a few.

But some considerations should be taken into account before making the switch to a PTFE O-Ring .

1966 Mr. America & Sports Performance Pioneer Bob Gajda Discusses Bodybuilding Experiences (Part 1)! buy anavar bpi bulk muscle gainer review, crazy bulk reviews bodybuilding | profile While PTFE offers some distinct advantages over elastomers, it also has some draw-backs that can negatively affect seal performance.

Eclipse offers fully customized PTFE O-Ring sizes out of our full range of PTFE blends that can help boost performance and longevity for your seals. But in some cases, an Eclipse Spring Energized seal might be the best choice for optimal sealing performance.

Here’s how to determine whether a PTFE O-Ring or Spring Energized seal is the best for your application.

Advantages of PTFE O-Rings

Chemical compatibly is often one of the first things checked when specifying an O-Ring material.

Corrosion resistance

Media that isn’t compatible with typical rubber compounds, or caustic or corrosive chemicals can make PTFE the best choice of material.

PTFE is impervious to almost all industrial chemicals, making it one of the most corrosion resistant materials available throughout all industries. And it the integrity of rubber compounds is being compromised by chemical attack, then PTFE may do the trick.

Long shelf-life

Applications requiring long-life or extended service intervals in corrosive environments may also merit the use of PTFE.

While some elastomers might survive for the short term or in intermittent exposure, degradation over time might result in problems years down the road, whereas PTFE’s resistance properties will remain indefinitely.

Wide temperature range capabilities

PTFE’s temperature range capability of -325°F to +500°F is also well beyond the range of most elastomers.

Applications in cryogenics or high temperature situations such as ovens or combustion processes may also rule out any elastomer compound, again making PTFE the best choice.

Extremely low temperatures will cause most rubber compounds to harden to the point where any elastomeric properties are no longer present in the material. This combined with contraction of the material can mean it will no longer function effectively as a seal.

PTFE, on the other hand, retains flexural and pliability properties even at cryogenic temperatures.

Additional Benefits to PTFE O-Rings

PTFE has some additional advantages over rubber compounds as well:

The Disadvantages of PTFE O-Rings

While chemical attack or extreme temperature might not leave any choice besides PTFE, there are some disadvantages to the material that could affect your project.

Higher hardness

Virgin PTFE’s hardness is 55 Shore D, which is much harder than a typical Nitrile O-Ring at 70 Shore A, which is a softer scale.

The higher hardness negatively affects sealability, as the material doesn’t conform the mating hardware surfaces as easily.

Leakage rate

While rubber O-Rings might conform to “as machined” surfaces, PTFE may require post-process surface finish improvements to control leakage to acceptable levels.

In general, under normal conditions, the leakage rate for a PTFE O-Ring will be higher than any elastomeric compound.

The use of a PTFE O-Ring isn’t recommended for applications that don’t require extreme temperature or severe chemical conditions.

Inelasticity

PTFE’s nature as an inelastic material means that reuse or multiple installations of the same seal will not be possible.

Unlike rubber compounds, PTFE will not return to it’s original shape and cross-section once deformed during installation and use. That means PTFE O-Rings are typically only recommended for static face seal or flange type configurations that are not actively engaged and disengaged.

For example, a PTFE O-Ring would not be recommended for a chamber door seal that needs to be opened and closed frequently, as the O-Ring would likely have to be replaced after every use.

A reused PTFE O-Ring may look and perform similarly to a standard rubber O-Ring suffering from extreme compression set. But unlike rubber, this compression set occurs after only one use.

More often, PTFE O-Rings are found in flange gasket type applications where the seal will remain static and undisturbed until the next service interval.

When to Choose an Eclipse Spring Energized Seal

When deciding whether to use a PTFE O-Ring for your application, the benefits of a spring energized seal should also be taken into consideration.

A spring-energized seal will retain all the benefits of using PTFE as a sealing material, but won’t be subject to the disadvantages PTFE has on its own.

Incorporation of a metallic spring within a seal jacket will allow the PTFE to be energized at all times.

The inelasticity and cold flow tendencies of PTFE no longer become a problem with the spring of a spring energized seal, which ensures the good contact of the sealing surfaces under all conditions. This allows high cycle rates and repeated installations to be possible with a spring energized seal.

Spring energized seals also provide improved sealabilty and friction performance compared to a PTFE O-Ring.

In applications where PTFE O-Rings need to be replaced often, a spring energized seal may be a better choice.

Custom PTFE O-Ring Sizes and Materials from Eclipse

PTFE O-Rings are prevalent in the seal market and can often be sourced off-the-shelf. But selection is usually limited to Virgin PTFE, as the material and sizes to AS568B standard dash numbers.

Eclipse’s in-house machining capabilities and expertise means custom O-Ring cross-sections and diameters can be made-to-order, without tooling cost.

Correct Sizing

Eclipse is often approached by customers who are rebuilding old equipment, or machinery sourced from over-seas that may not use standard O-Ring sizes.

When using PTFE, the correct size for an O-Ring becomes more critical since it won’t stretch or conform as easily as a rubber compound would.

In a situation where a standard dash size is in-between two diameters, it’s usually possible to stretch the smaller size elastomer O-Ring into a groove. Though this might not be possible with a PTFE O-Ring, so a custom machined size may be necessary in this instance.

Made-to-order machining also allows custom size cross-sections to adjust the squeeze or compression of the O-Ring.

High or low pressure customization

In high-pressure situations where high clamping force can be provided, a thicker than standard cross-section may improve sealing performance by increasing the squeeze and therefore contact area and force.

On the other side, an application where clamping loads are light or friction is a concern, a smaller than normal O-Ring cross-section could help meet application requirements or allow for proper assembly of the hardware.

Wide variety of PTFE blends

Custom machining by Eclipse also allows customers to choose O-Ring materials from Eclipse’s full line of PTFE blends and Polymer seal materials.

The addition of fillers to Virgin PTFE can greatly improve the mechanical properties, stability, and wear resistance. Glass-fibers or Graphite fillers can enhance mechanical properties and wear life significantly.

In applications where high pressure extrusion is an issue, a filled PTFE can drastically enhance performance and extend seal longevity.

Other fillers, such as the solid lubricant Molybdenum Disulfide, can considerably reduce friction in dynamic applications.

The presence of an internal lubricant will reduce interface surface temperatures, which is beneficial to enhancing durability and prolonging seal life.

Eclipse’s non-PTFE based polymers such as UHMW and Thermoplastic Elastomer are also readily available if the unique properties of those materials is better suited for the application.

Spring or O-ring energizers can extend the normal limits of PTFE and plastic materials to deliver durable ultra-tight sealing capability. Discover how energizers work and how they can elevate your next sealing challenge >

Understanding How to Apply AMS3678 Specifications for Highest Quality PTFE

Fri, 04 May 2018 15:00:00 GMT

AMS3678 is a standard maintained by SAE International. What makes this standard so important is that it applies directly to the seal and machined bearings industry.

AMS3678 details standard physical requirements for virgin PTFE. But this standard also dictates requirements for 15 other blends of PTFE that are commonly used to manufacture seal, wear ring and back-up ring components.

How is AMS3678 Applied?

The specifications laid out in AMS3678 are meant to be applied to PTFE shapes that are manufactured by machining from molded stock. This makes it a particularly useful quality control tool for components in the sealing industry.

While seal designers have always been able to specify key features, industry standards for PTFE and PTFE compounds were lacking in scope. These standards also weren’t broadly accepted in the manufacturing industry.

Certain MIL, AS and ASTM specifications have traditionally been applied to seals. But these specifications were only applicable to virgin PTFE, and often contained requirements that weren’t essential to the functionality of seals, wear rings and back-up rings.

Why is AMS3678 Important?

AMS3678 dictates what the minimum physicals requirements are for tensile strength and elongation, as well as a specified range for specific gravity. Additionally, a separate test is performed to determine that molded material is dimensionally stable.

This combination of requirements fully defines the product needed to ensure that consistent performing components can be manufactured.

This methodology is applied to all 16 PTFE resins listed in the specification, which gives the designer great flexibility and confidence when choosing a material.

Since the AMS3678 process is set up to match physical test reports with specific material batches, the added benefit of material traceability is intrinsic with the manufacture of the specified material.

As regulatory agencies demand more transparency, this can be an extremely useful specification to ensure you’re maintaining proper documentation.

Make the Right Choice with Eclipse

Whether you’re required to follow AMS3678 protocol or have decided it’s the best choice for your business, Eclipse can provide the best quality product for your next project.

We work closely with SAE International, as well as base resin manufacturers to stay current with the latest specification revisions.

When you choose Eclipse, you get the benefits of our AS9100 quality system, along with verified AMS3678 processes.

Specifying material per AMS3678 streamlines the approval processes between the engineering, purchasing and quality control departments. Just specify the specific compound you need for your project, and Eclipse will manufacture and certify the seal.

A full list of these materials can be found on www.sae.org , but we highly encourage you to contact one of our engineers to discuss specific application requirements to make sure the best material is chosen for your specific project. Contact us today to get started >

Seals for Supercritical CO2 Cannabis Extraction

Wed, 25 Apr 2018 15:00:00 GMT

With the marijuana and cannabis industry taking in nearly $9 billion in 2017 and projected to more than double to $21 billion by 2021, the market is primed for innovation in production volume and technology.

The growth in popularity of vaporizers, infused edibles, and topical cannabis products means the demand for cannabis oil extraction is a fast multiplying industry.

The two primary means for oil extraction is via petroleum based solvents such as butane or propane, or by supercritical fluid extraction (most often carbon dioxide, or CO2).

The Benefits of Supercritical Fluid Extraction

Supercritical Fluid Extraction (SFE) has a few distinct advantages over using petroleum solvents.

How Supercritical CO2 Cannabis Extraction Works

CO2 has to be in liquid form to be efficiently pumped. So the CO2 extraction process starts with a cooling cycle, often down to -70°F.

Once pumped into a high-pressure chamber, the CO2 can be heated to begin the process of converting into the supercritical state.

Once above a temperature of ~90°F and a pressure of ~1100 PSI, the CO2 will be supercritical where it exhibits the properties of both a gas and a liquid. While having the density of liquid, it will still expand to fill a container like a gas.

The supercritical CO2 is then mixed with the raw cannabis. The extraction pressure is often very high, usually around 5,000 PSI, but this can vary depending on the substance being extracted.

The unique properties of the supercritical CO2 allow it to easily pass through membranes in the cannabis and dissolve the desired oils.

The collection process begins by passing the CO2 with the dissolved compounds into a low-pressure vessel and into a separator. By controlling the pressure, various compounds can be selectively precipitated out.

The CO2 can then be cooled, re-compressed and recycled.

Increased Longevity and Durability Through Eclipse Seals

SFE has been around for decades, and has been used in a wide variety of industries, including decaffeinating coffee and extracting essential oils. But the new and growing demand of the cannabis industry has raised the need for increased volume and reduced cycle time to new heights.

Eclipse has been approached by multiple customers looking for increased longevity and durability of seals in their existing extraction equipment.

Increased duty cycles have proven standard O-Ring and rubber seals have not been up to the task of the heavier use.

While an O-Ring might seal a chamber door of a pressure vessel adequately, it’s only a matter of time before compression set occurs and leakage starts to take place.

An O-Ring in a less accessible part of the extraction equipment might mean costly down-time for replacement.

At Eclipse, we successfully replaced these types of standard seals with spring energized seals utilizing our EH042 Thermoplastic Elastomer material .

The EH042 Advantage

EH042’s exceptional toughness and pliability make it perfect for high pressure gas sealing.

The incorporation of a spring within the seal means compression set will never be an issue and extended service intervals and duty cycles will be possible.

Within a standard CO2 extraction process, EH042 is also virtually immune to explosive decompression unlike many standard rubber products.

The depressurization cycle of the process has the potential to be greatly reduced without risk of damaging the seals, which increases overall productivity.

The Solution to Swelling O-Rings

Some of our customers have reported swelling of O-Rings within the system due to permeation of the CO2.

Swelling can cause over-occupation of the O-Ring groove and potentially result in dynamic components locking up.

Eclipse has multiple seal materials insusceptible to swelling caused by CO2 including EH042 and a wide variety of PTFE blends.

->We also provide sealing solutions to newly designed SFE equipment that’s intended to take production volume and capacity to the next level.

This means larger vessels, increased pressures and flow-rates all stressing seal components more than ever. Our spring energized seals can ensure optimal pressure handling and a long service life of the whole system.

Contact us today if you think your extraction equipment can benefit from the advanced seals and expertise our team at can provide >

EZ032: An Extreme Material for Extreme Applications

Tue, 06 Mar 2018 15:25:00 GMT

Every day, Eclipse works to push the limits of engineering and product requirements in a variety of industries. As surface speeds and temperatures are driven to extremes, wear resistance becomes an increasingly important factor to ensure long sealing wear life.

While heavily-filled PTFE materials such as glass/carbon/PPS blends have been available for years, even these have fallen short of expectations in the most demanding applications presented by our customers.

Luckily, Eclipse has a new material weapon at our disposal to meet the challenge: our EZ032.

What is EZ032 and What Makes It Special?

Eclipse’s EZ032 is a high-percentage fill blend of carbon, carbon fiber and Modified PTFE.

Proprietary blending technology is used to evenly disperse carbon and fiber fillers throughout the base resin imparting wear resistance and high temperature capabilities.

What makes EZ032 a unique material is how the resin blending allows for a high level of fillers to be added without degrading the properties of the base resin.

Typically, higher filled resins don’t lend themselves to being used in seals. In the case of EZ032, the desired properties of pliability and resiliency still remain, making this material useful in critical sealing applications where high pressure-velocities are present.

Where Should EZ032 Be Used?

Where wear or temperature resistance is the name of the game, EZ032 should be considered.

Eclipse has specified EZ032 with great success in linear bearing applications running continuously at 575°F and rotary sealing applications with Pressure-Velocities above 150,000.

With EZ032, Eclipse has manufactured effective solutions for multiple downhole rotary sealing applications where surface speed, temperature and abrasive media were too much for other materials.

Switching to EZ032 in a certain gear pump application increased seal wear life over 20%, which means 20% fewer rebuilds and associated downtime. That also means increased profitability for your team.

Contact Eclipse today to see if EZ032 can make a difference in your extreme applications, including the following:

How Pressure Velocity Affects Seal Performance

Fri, 19 Jan 2018 18:26:00 GMT

Wondering why that leak you fixed on your equipment just a few weeks ago is back to haunt you? There’s a chance it could be the type of seal you selected.

Your choice of seals has a direct impact on the performance of your equipment. Chosen wisely, the right seal can help prevent leaks, reduce friction, and extend the life of your machines.

There are a number of factors to consider while selecting a seal , including pressure, load, temperature, speed, media (or lubricant) in which they operate, and hardness and surface finish of surrounding materials.

And one of the most significant factors among these is the pressure-velocity, or PV, of your seal.

How to Calculate Pressure Velocity

Seals have a specific range of PV values in which they operate optimally, called the PV limit.

The PV limit for a seal is defined as the highest combination of pressure and velocity at which that seal operates with normal wear. Beyond this limit, the seal experiences severe wear.

It’s important to determine the PV in your equipment to choose the right seal for your application.

For practical applications, the PV limit of a seal also depends on other factors, like operating temperature and compatibility with the lubricant.

PV is given by the product of pressure of the media (in psi) and velocity of the shaft (in feet per minute).

For example, for a reciprocating engine with a 1” rod and a 3” stroke, operating at 100 cycles per minute, with a media pressure of 500 psi –
PV = 2 * [Stroke Length (in ft.)] * [Cycle Rate (cycles/min.)] * [Pressure (in psi)]
In this case, PV = 2 * (3/12) * 100 * 500 = 25,000 psi-ft./min.

For a rotary engine with a 4” rod, operating at 1000 rpm and 50 psi,
PV = [Circumference (in ft.)] * [Speed (in rpm)] * [Pressure (in psi)]
For this example, PV = (4/12) * 1000 * 50 = 52,360 psi-ft./min.

PV Values and Seal Choice

It’s easier to choose the type of seal for your application once you’ve determined the PV value.

Eclipse offers a variety of seals for different applications — Rotary Lip seals , Spring Energized seals , O-Ring Energized seals .

The following charts illustrate the seals best suited for specific PV values:

Dynamic Applications of PV Values

Reciprocating

Rotary

Static Applications of PV Values

In general, at higher temperatures, the PV limit and pressure rating decrease and wear rate increases. Anything that can reduce heat generation, such as the presence of a compatible lubricant, reduces seal wear and aids prolonged operation at high PV.

Spring Energized Rotary seals are usually employed in high-pressure, low-speed applications, while Cased Lip seals are more suitable for low-pressure, high-speed applications.

Pressure-Velocity Curves for Spring Energized Rotary and Cased Lip seals

Important note: Any PV values to the right of the curve fall under the severe wear zone, while those to the left of the curve belong to the mild wear zone.

Eclipse Spring Energized Rotary seals

Velocity (in surface feet per minute)

Eclipse Cased Lip seals

Velocity (in surface feet per minute)

Ideally, rotary seals should stationary, and shouldn’t rotate in their glands. Seal rotation increases wear and could cause leakage of the lubricant.

To prevent unnecessary wear, the spring load on rotary seals should be just enough to ‘lightly compress’ the seal and achieve a good fit.

The seal needs to be in contact with a smooth surface like that of a shaft (and not with a relatively rough surface like the housing), so that the joint is ‘plugged’, preventing potential leakage of the lubricant.

Choosing the Right Seal for Your Application

PV values play a critical role in seal-selection. While selecting the right kind of seal is crucial, it’s also important to install and maintain the seal effectively to maximize its shelf life.

Poor installation and inadequate maintenance could result in leakages and accelerated wear.

But these issues are easily remedied by thorough understanding of the various kinds of seals, sealing materials and seal-selection considerations available. That’s where Eclipse comes in.

As the only seal manufacturing company that also specializes in engineering, we can help you determine if a standard off-the-shelf product would fit your needs, or if an engineered solution is necessary to get the job done right.

Eclipse can produce the exact seal, bearing or spring that you need. We also carry a wide variety of materials including plastic, rubber, nylon and thermoplastic elastomer, and can manufacture a product unique to your needs. Contact us today to find the best seal solution for your next project >

Best Uses of 3 Energizer Spring Types

Tue, 21 Nov 2017 22:06:00 GMT

When looking into an energized seal for your needs, there are 3 configurations of spring to consider: Cantilever “V” Springs, Helical Wound Springs, and Canted Coil Seals .

Each spring type has a unique advantage depending on a certain set of conditions. Below are the advantages of each energized spring type and their ideal use.

Why do I Need an Energized Seal?

The primary reason to consider a metal spring energizer is to overcome the limitations of the polymer seal jacket.

Polymers offer the compliancy necessary to create a seal, but in order to maintain sealing over a broad range of application parameters, a method of consistent loading is required.

Eclipse spring energizers fulfill these requirements by providing energy to overcome varying temperatures, pressures and hardware tolerances.

Benefits of Cantilever “V” Springs

A Cantilever “V” Springs is a commonly specified spring type. This “V” shaped spring offers very predictable loading, which makes it great for general use.

With a linear load curve and excellent deflection range, Eclipse Cantilever Springs are a highly versatile product.

The shape of the spring concentrates load on the front of the seal, which makes this design suitable for use as environmental excluders and for applications requiring scraping of viscous media.

As an additional option, the spring cavity area can be filled with silicone for FDA clean-in-place applications

Best Applications

Benefits of Helical Wound Springs

Helical springs are constructed of wire ribbon wound into a circular helical shape.

This helical shape spring affords a relatively high load versus deflection range resulting in a seal product that can provide very tight sealing.

As a highly loaded product, Helical Spring Seals should be considered when dynamics are very slow or static.

Best Applications

Benefits of Canted Coil Seal

Canted coil springs are constructed from spring wire, formed into a circular and canted shape.

The canted coil is unique in the sealing industry because of its broad, consistent loading curve.

As an engineered loading device, canted coil springs display a very constant load over a large deflection range.

This feature allows Canted Coil Spring Seals to operate in friction sensitive applications.

We stocks several sizes, materials and loads to optimize the seal for the application.

Best Applications

These Eclipse spring types offer the designer a product to address any application concern. Contact us to discuss the optimum energized seal solution for your project >

Designing Glands to Avoid O-Ring Extrusion

Mon, 20 Nov 2017 23:23:00 GMT

O-ring extrusion can cause fluids or gases to leak, not to mention costly equipment downtime. In high pressure applications, it can be disastrous, even dangerous, for workers.

Here’s how to avoid O-ring extrusion by considering O-ring material, clearance gaps, and backup rings.

How Does an O-Ring Work?

In dynamic applications, an O-ring is typically used to seal between a rod or piston and a cylinder wall.

Piston O-Ring:

An O-ring sits in a gland, or groove, which holds the O-ring in place while allowing flexible deformation as it is squeezed between a rod or piston and cylinder wall.

This compressive elasticity is necessary to provide a tight seal to exclude fluids or gases effectively.

What Causes O-Ring Extrusion?

O-ring seal extrusion is like a bicycle tire tube bulge — where part of the tube squeezes out through a crack in the tire, making the tube vulnerable to bursting.

Another example of extrusion, but intentional in this case, is squeezing glue out of a tube. As the glue gets older, it can dry out, becoming thicker and forming a crust that constricts the nozzle.

The thickness and constriction make it harder to squeeze the glue out, requiring more pressure.

This is the reverse of seal applications where we don’t want extrusion to happen.

Seal extrusion depends on:

O-ring extrusion is more possible in applications where pressure exceeds 500 psi. To mitigate the risk, O-rings need to be sufficiently firm with a close enough clearance gap.

Hardness and elasticity

Like all seals, O-rings need to be sufficiently squeezable to create a good seal between hard surfaces (usually metal). They also need to be firm enough to avoid excessive deformation and extrusion.

There are two main ways to measure O-ring resistance to extrusion:

Modulus of Elasticity

The Modulus of Elasticity defines a material’s resistance to elastic deformation. This is calculated as the ratio of stress (force) over strain (movement) — measured by stretching samples on a Tensometer.

Stress (force) : Strain (movement)

This is usually defined at 100% elongation (double its original length). It can also be reported at other percentages of elongation where figures can be different due to non-linear properties.

Shore A Durometer

The Shore A Durometer scale defines material hardness as a figure from 0 (soft) to 100 (hard). This correlates to increasing Modulus of Elasticity.

Standard O-ring material hardness is about 70–75 on the Shore A scale. With special additives, O-rings can be manufactured for hardness of 90–95 Shore A for high-pressure applications.

In certain instances, just this change in durometer is enough to halt the o-ring extrusion.

Clearance

Piston/rod clearance from a cylinder wall can also be defined two ways:

Diametrical Clearance:

the total difference between the piston/rod diameter and the bore diameter.

Radial Clearance:

the gap between the piston/rod and the cylinder bore.
The greater the clearance, the more likely the o-ring will extrude through the gap for a given pressure and o-ring material hardness.

O-ring Large E-Gap Extrusion:

O-ring Small Gap Extrusion:

You can see how this works from the bicycle example above. The bigger the tire crack, the more likely the tube will squeeze through, and even more so as you pump the tire up with higher pressure.

Reducing piston or rod gap, for the same O-ring, can be an effective remedy for O-ring extrusion. You can get away with a softer O-ring or safely allow higher pressure fluids or gases in the application.

O-ring groove depth and width are also important for effective seal functioning but aren’t critical for extrusion mitigation.

How Backup Rings Provide an Effective Solution

If an O-ring is close to extrusion because of unavoidable material softness/flexibility, pressure, or clearance gap, an effective fix is a backup ring on one or both sides of the O-ring.

Sufficient lateral room is required in the gland (slot) to accommodate the backup rings as well as the O-ring. If not, the gland needs to be re-designed.

Backup rings can take O-ring resilience to another level in demanding operating environments.

Find out more about Eclipse’s robust quality O-rings and backup rings to fit your application. Learn about the history of the O-ring >

Why Do PTFE and Other Plastic Seals Need Energizers?

Fri, 20 Oct 2017 16:04:00 GMT

As the operating parameters of industrial technologies and manufacturing processes get more extreme, the need for optimal sealing solutions become that much more important.

Elevated temperatures and pressures, higher speeds, extreme environments, faster gas decompression, and aggressive medias all make sealing more critical. This extends right across static, reciprocating, rotary, and oscillating applications.

This challenge has been met very effectively by the inventive addition of energizers to seals. Energized seals give the ultimate performance in the most demanding conditions and critical applications.

Spring or o-ring energizers can extend the normal limits of PTFE and plastic materials to deliver durable ultra-tight sealing capability. Here’s a rundown of how energizers work and how they can elevate your next sealing challenge.

How Energizers Work

PTFE has highly effective physical characteristics for seals, including low friction, heat tolerance, and chemical inertness. However, PTFE also has limited flexibility and elasticity.

Cantilever spring seal

The addition of a spring or o-ring behind a PTFE seal lip adds a persistent ‘springy force’ or ‘energy’ to press the lip against a metal surface such as a rod or cylinder.

Canted coil seal

When a seal is installed into a gland/cavity, the seal lip and spring (or o-ring) are compressed radially – providing a resilient pressure against contacting surfaces. This creates a tight and consistent seal, preventing leakage of fluid or gases.

Channel seal – piston

Benefits of Energizers

The resilient pressure of an energizer compensates for and overcomes several practical problems, including the following:

Lip pressure

Even after the lip material wears down over time, the energizer continues to push the lip tightly – otherwise the seal would become loose and leaky.

Adaption to deformation

With deformation of metal components contacting a seal (rods, shafts, cylinders, housings), energized lips adaptably fit around ‘humps and hollows’ to maintain sealing.

Adaption to misalignment

When components are misaligned, such as with eccentric deflection, energized lips dynamically move in and out to maintain close contact.

Picking up the slack

Manufacturing tolerances and clearances are not critical, as energized lips can ‘take up the slack.’ Thermal expansion and contraction can be likewise accommodated

Optimal Performance at All Pressures

The radial pressure maintained by a spring or o-ring keeps sealing lips in contact with mating surfaces even before fluid or gas pressure is applied, providing good low pressure sealing capability.

When system pressure is applied, energizer action is intensified – increasing the force on lips to make a tighter seal. The radial pressure is always higher than the pressure of the fluid or gas to be sealed.

Energizer Options to Meet Your Needs

Eclipse offers a wide range of high-performance spring and o-ring-energized seals to meet rigorous demands. Contact us to find out how energized seals can cost-effectively serve your critical applications.

The Advantages of Composite Marine Bearings

Mon, 25 Sep 2017 17:17:00 GMT

From bushings between propeller shafts and ship hulls and brushings for rudders, marine bearings are a critical component in a range of marine hardware.

As the ship-building industry continues to advance in higher operating efficiencies and enhanced safety performance, ship operators need alternative solutions to reduce costs and extend service periods between maintenance overhauls.

Composite materials are replacing traditional bronze in a growing range of marine bearing applications. These advancements in materials offer ship owners a variety of key advantages, including:

Composite materials offer many maintenance-free solutions to prevent galvanized corrosion, improve grease and oil systems, and more.

From the ship maneuvering system to deck equipment, here’s how composite materials are enhancing the operation and longevity of marine bearings.

Applications of Marine Bearings

Beyond the under-water applications of marine bearings listed above (bushings between propeller shafts, ship hulls and rudders), there are also many above-water applications for marine bearings. This includes deck hatch covers and roller bearings.

Sizes for marine bearings range from small applications of one-inch diameter up to huge scale applications that exceed 30 inches for large ship propeller shafts.

The Advantages of Composite Materials

Ship owners have a great need to keep maintenance and downtime of their marine bearings to a minimum, while looking for performance improvements. This is where composite materials come in.

Replacing traditionally bronze or wood bushings with composite materials can help alleviate lubricant discharges, prevent galvanized corrosion of dissimilar metals, and more.

Propeller shaft and rudder bearings made from composite materials are ideal for replacing rubber-lined, wood, and bronze bushings.

Composite bearings can also have axial grooves machined into them to provide better water flow and lubrication.

Below are the ship operations which can be improved with composite marine bearing materials.

Ship Maneuvering Systems

Side thrusters are used to make ship docking controllable and safe. They consist of a propeller in a ‘tube’ running from the left to the right side of the hull near the bow.

Side thrusters have traditionally used greased bronze bearings, but water-lubricated composite materials can extend the life of bearings while reducing vibration and promoting smooth quiet operation.

Stabilizer Systems

Lubricant discharges from fin stabilizers have prompted marine operators to look for alternative solutions to grease and oil systems.

Although environmentally acceptable lubricants are tolerated, a better option is to replace grease and oil bearings with water-lubricated composite alternatives.

Deck Equipment

Composites have successfully replaced bronze in a variety of deck equipment applications, and can work above or below the water line without the need for grease lubrication.

They can offer maintenance-free solutions that isolate dissimilar metals, preventing galvanic corrosion and providing electrical isolation of deck components.

Applications include fairlead rollers, winches, capstans, stern rollers, A-frames, davits, cranes, skidding pads, and hatch covers.

Eclipse offers high quality solutions for composite bearings optimized for a range of marine applications. Find out how you can get better performance and longevity from your marine bearings to improve your operational efficiency today >

How to Avoid Stick-Slip in Your Seal

Fri, 15 Sep 2017 21:14:00 GMT

Stick-slip is a common phenomenon that can occur in seals due to uneven friction between objects sliding across each other.

This repetitive start-stop movement or vibration known as stick-slip can cause major issues and even failure of mechanical systems, including seals. However, proper seal design and knowing what to look for can help you avoid stick-slip in your machinery’s seals.

Here’s why stick-slip happens and how you can prevent this problem in your seals.

Stick-Slip in Everyday Life

Stick-slip is familiar experience for most of us in our everyday lives. Think about when objects require more force to start their motion than to keep them in motion — like when you’re trying to slide a heavily-loaded cardboard box along a hardwood floor.

You have to give the box a strong push to overcome the friction of it ‘sticking’ to the floor. But once it starts ‘slipping’ across the floor, the movement is much smoother. If you slow down, getting the box moving again can be jerky.

Another example of every-day stick-slip is when earthquakes are generated by the rapid slipping of fault lines that have long been stationary under pressure, then suddenly give way.

Stick-Slip in Machinery

Stick-slip vibration can be commonly heard in hydraulic cylinders and in rotational systems such as creaking hinges or screeching brakes. Two different types of friction can contribute to stick-slip: static and running friction.

Static Friction

Static Friciton or stiction (‘static’, ‘starting’, or ‘breakout’ friction) is the amount of force required to start an object’s motion along a surface.

This force is greater than that required to sustain the motion – which is the ‘running’ or ‘dynamic’ friction. The difference is bigger if the object has remained still for a long of time and gets stuck.

Running Friction

Running friction has two components: coulombic and viscous drag. Coulombic or ‘dry’ friction is dependent on the direction of motion, and has constant magnitude. Most mechanisms also have some viscous drag that is proportional to velocity.

Why Does Slick-Slip Occur?

The sudden difference between static and running friction causes jerkiness when an object transitions from stationery to movement, and back again.

Stick-slip is not yet completely understood by physicists. It’s generally agreed that stick-slip results from “common phonon modes between surfaces in an undulating potential well landscape primarily influenced by thermal fluctuations.”

However, in practical experience, the causes of stick-slip and uneven motion are well known. From surface compatibility to frictional heat temperature to cycle speed, stick-slip can happen when there is failure or misalignment with any of these factors.

How to Avoid Stick-Slip in Your Seals

Stick-slip in seals can cause softening, swelling, binding, drag, wear, and even failure in a mechanism. Here are the key factors to look out for to avoid stick-slip in your seals:

Proper seal selection and design can eliminate or drastically reduce stick-slip. Eclipse has the expertise to fix all seal problems in your mechanisms and find optimum solutions for specific applications. Contact us to discuss your seal problem and get a trouble-free solution.

4 Things You Need to Know About the 2017 Solar Eclipse

Mon, 21 Aug 2017 13:37:00 GMT

On August 21st, 2017, millions of sky-viewers across America will be cast into darkness for over two minutes while the moon moves between the earth and sun. As our company name draws inspiration from this powerful cosmic occurrence, we wanted to share important tips about the upcoming 2017 solar eclipse.

Here are 4 things you need to know about the upcoming celestial spectacle known as the “Great American Eclipse.”

1. It’s a Total Eclipse

The 2017 August solar eclipse is a total eclipse, which means the moon will block out the sun more completely than during a common annular eclipse.

Americans haven’t been able to witness a total solar eclipse in 38 years. A total solar eclipse won’t be viewable in North America again until April of 2024 .

2. You Can See the Total Eclipse in 14 States

Although every state in the US will see some percentage of the sun disappear during the eclipse, parts of 14 states will be able to see the total eclipse. These states include of Oregon, Idaho, Montana, Wyoming, Nebraska, Kansas, Iowa, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina and South Carolina.

The states that will be passing closest to the center of the total eclipse’s path will see the sun disappear for about two and a half minutes . Carbondale, Illinois is the city closest to the path of totality — viewers in this city will see 2 minutes and 42 seconds of darkness.

3. Never Look at the Eclipse Without Protective Eyewear

Whether you’re in a city that’s directly in the total eclipses’ path or can only see a percentage of the eclipse, you should never look directly at the sun without protective eyewear . And protective eyewear doesn’t mean regular sunglasses.

NASA recommends eclipse glasses which meet a safety standard to protect your eyes from harmful UV rays. There are many fake products presently being sold, so be sure to check out this American Astrological Society’s list of reputable vendors for eclipse glasses and filters .

4. You can watch it via NASA TV

Although the Great American Eclipse will likely be one of the most unique and exciting celestial occurrences of a lifetime, if you reside outside the path of totality or can’t make outside to see the eclipse, you can watch real-time coverage of the event on NASA Television .

This livestream will provide breathtaking imagery of the eclipse captured by 11 space crafts, three aircrafts, and 50 high-altitude balloons. Even the astronauts of the International Space Station will be providing live-streamed coverage from their orbiting satellite.

Eclipse Engineering is a top tier supplier of high-precision seals for the aerospace industry. Learn more about our solutions to support your aerospace operation .

Seal Contaminants: What They Are and How to Prevent Them

Mon, 19 Jun 2017 18:26:00 GMT

Neglecting routine maintenance can cost you in seal performance or, in some cases, end with catastrophic failure. Prolonged downtime will incur losses that exceed the temporary cost of preventative maintenance.

It’s important to identify seal contaminants and their sources before they turn into larger issues. Here are some tips on what to look for and how to deal with them.

Common contaminants

Inspections: what to look for

Some of the above contaminations are easier to detect than others.

For cylinders and actuators, take note of scoring, putting or accumulated hydraulic fluid on pistons/rods, which could indicate that metal particles have got into the system. If so, the system’s oil needs to be drained, and the entire system flushed out. Seals need to be inspected for damage and wear and thoroughly cleaned or replaced.

Consider any strong or unusual smells, which may indicate your system is operating at excessive temperature, fluids are leaking onto high-temperature surfaces, or fluid viscosity has been compromised.

Remember that if fluids can get out through seals, contaminants can get in. A hydraulic fluid leak could indicate serious damage to your system and spell major cost to your business.

You can’t usually see contaminants within fluids with the naked eye, so fluid sampling and chemical lab analysis is required. Particle count is a good measure of contamination and its damage potential.

Putting it right

Once you know which contaminants are present, you can find out their source and how to eradicate or minimize them.

Even without contaminants present, it’s crucial to check the condition of your seals and replace them if necessary with better suited ones.

The Right Fillers for Optimum PTFE Performance

Wed, 07 Jun 2017 18:48:00 GMT

Polytetrafluoroethylene (PTFE) resin is a highly effective material for seal consumers due to its extremely low friction, high heat tolerance and chemical inertness.

With the right additives, PTFE resin can perform even better in terms of strength, thermal performance, chemical resistance and abrasion.

However, there are a few design considerations when using PTFE resin, particularly when combined with glass fiber and bronze.

A Quick Intro to PTFE: A Breakthrough Material

A common household form of PTFE is Teflon, which you’ll recognize as the slippery plastic used in non-stick frypans.

PTFE was discovered in the 1930s as an accidental byproduct in chlorofluorocarbon refrigerant production. It’s a synthetic compound consisting wholly of carbon and fluorine — a fluorocarbon.

PTFE is hydrophobic, so doesn’t get wet due to the high electronegativity of fluorine. It’s also chemically non-reactive, mainly because of the ‘independent’ strength of the carbon–fluorine bonds. This suits the resin well for reactive and corrosive chemical environments.

Where it is used as a lubricant or seal, PTFE has the huge benefits of reducing friction, wear and energy consumption of machinery.

Making a Great Material Even Better

After extensive experimentation and time-tested performance, the following additives/fillers have come to be strategically used to enhance PTFE performance:

Glass Fiber (typically 5–40%)

Improvements:

There are a couple of cons to glass fiber, including abrasion on mating parts and discoloration of finished parts.

Ideal for:

Molybdenum Disulfide (MoS2) (typically low %)

Improvements:

Ideal for:

Carbon powder (typically 5–15%)

Improvements:

Ideal for:

Carbon Fiber

Improvements:

Ideal for:

Graphite (typically 5–15%)

Improvements:

Ideal for:

Bronze (typically 40–60%)

Improvements:

Disadvantages:

Ideal for:

Pigments

Improvements:

Put to Profitable Use

PTFE seals , with their exceptional performance, are used for a myriad of applications, including:

Find uniquely blended filler-enhanced PTFE seals to meet your needs >

Eclipse MicroLip: High Performance in a Small Package

Sat, 22 Apr 2017 22:08:00 GMT

Industries demand a high sealing capability with a small footprint.

Emerging industries such as robotics, mobile hydraulics, aerospace and medical are under increasing demand to scale down their designs while simultaneously increasing performance. These demands lead to higher pressure and velocity requirements for seals.

The MicroLip Advantage

The Eclipse MicroLip is unique because it is constructed of precision-machined components. Fabricated on high-speed turning centers, the components can be optimized and customized to fit in tight spaces.

Cased PTFE lip seals are not new in the industry, however, the MicroLip takes these high-pressure velocity seals and packs them in a smaller hardware envelope than ever before.

Metal-cased seals have been the top choice for demanding rotary applications for decades. The MicroLip offers designers new opportunities to improve the life and efficiency of their machinery, ultimately leading to a competitive edge.

Quick Turn Prototyping

Because the MicroLip is machined from stock metals and the Eclipse range of ET and EZ materials, stamping dyes, forming fixtures and material minimums do not apply.

This allows our design team to specify a seal that fits the exact needs of the customer as well as supplying test seals in far less time than traditional metal-cased seals.

A Mighty Seal in a Small Package

The MicroLip was created as a result of customer requests for a highly capable seal that can operate at high rotary speeds, while maintaining pressure resistance and leakage control during hardware runout conditions.

As a result, we designed a seal from the ground up to specifically address these issues. Typical products in this range rely on stamped components that require a large amount of hardware space and offer low pressure rating and resistance to runout.

The MicroLip is assembled from precision-machined components allowing for high functionality in a small package. The seal element is machined to an optimized shape to achieve a high pressure rating while allowing more responsiveness.

This element, combined with a tight-wound compression spring, yields a seal solution unsurpassed in leakage control, responsiveness and pressure resistance. The MicroLip has been specified in applications above 20,000RPM, making it suitable for high-speed instruments such as surgical drills.

The MicroLip has also been employed at pressures over 250psi, making it a product of choice for mobile hydraulics.

In side-loaded applications, the MicroLip has been used to accommodate up to .005” shaft runout, allowing it to provide sealing in situations where external loading can cause shaft misalignment.

Robotics, semiconductor processing and small mixers are common applications for the MicroLip. An engineered solution especially suited for smaller rotary applications, the MicroLip is a mighty seal in a small package.

The Value for Oil & Gas Companies to Standardize on Single-Source Seals

Fri, 13 Jan 2017 09:00:00 GMT

Procurement for oil and gas projects has become very complex due to growing size, lethal environments, and demanding regulations.

Many oil & gas companies now split projects into multiple EPC (Engineering Procurement & Construction) contracts. This can naturally lead to mixing 10 or so different manufacturers’ products with disparate materials and specifications even though they come under the same industry standard.

In an industry where safety and performance are critical, this creates a potential quagmire of unmanageable complexity that risks cost-effectiveness, production loss, infrastructure damage, and injuries.

Consistent quality and integrity assuring performance

Multi-sourcing on critical asset components, such as mechanical seals, can compromise the safety of a whole project. Without oil & gas companies carrying out their own rigorous checks through the project, there is no way of knowing that fittings are fully tested and guaranteed to work together.

A transparent collaborative contract with a single-source supplier (for each range of components such as seals) means all parties including sub-contractors are clearly focused on delivering a robust solution that’s compliant to specified requirements.

Consistent standard testing and documentation is taken care of, providing extra reassurance and peace of mind for the oil and gas operator.

Tailored solutions with complete service

A single-source supplier takes greater ownership of a project, providing a completely integrated, dedicated, and comprehensive service––making life simpler and safer for the end client.

Saving on inventory management

It is challenging for end clients to keep track of the components that are being installed on their sites, especially over wide geographical areas.

A major benefit of single-sourcing for the end client is simpler stock management. It helps the client to reduce the risk of mixing different manufacturers’ components on site as well as keeping stock levels down––making operations more cost-effective in the long term.

Economy of scale bringing costs down

By supplying a larger volume of components, suppliers can deliver a more cost-effective solution for the oil and gas operator.

Getting the best results for oil and gas projects

As a single source for seal components, Eclipse can offer oil & gas clients the very best value, assured performance, consistent standards, and minimized risk of production loss, infrastructure harm, and safety breaches.

Find out more about what Eclipse can do for the oil & gas industry , with distribution of a wide range of perfect-fit mechanical seals including o-rings and gaskets.

AS9100 / ISO9001Certification!

Wed, 04 Feb 2015 16:31:00 GMT

Back in August 2013 we began the journey to gain AS9100 and ISO9001Certification . Up to this point, our size had allowed us to manage our organization by walking around and seeing what was occurring on the shop floor in real time. With the continual growth we were experiencing, it had become difficult to continue managing projects without guidelines in place. As an organization always looking to bolster growth and never stand still, we formed a management team and began the journey to become ISO/AS approved in the hopes that it could further strengthen our company. The process guided us in creating systems to run and organize our business in a more efficient manner. This process became instrumental in improving literally every aspect of our business, further allowing us to become more efficient while reducing or eliminating the number of errors in processing orders. Although it was a tremendous task upfront, documenting every process experienced in our building has allowed us to perform these operations more effectively when running jobs multiple times. This has also taken the guesswork out of our order entry and allowed those staff members to better utilize their time focused on contact with our customers instead of needing a detailed grasp of our production and how to make your job. With a process built for its attention to detail, minor changes to a product now require far less time to schedule and plan, at the same time reducing or eliminating errors that occurred due to oversight.

On November 4, 2014 we had our final audit, and subsequently on January 7 2015 received final certification and approval for ISO9001:2008 and AS9100C. The same day we received our certification, we were audited by an industrial/aerospace customer who gave us glowing reviews and opportunities for new business that came to light specifically because of our Quality Management System.

Congratulations to all the hard working folks at Eclipse that helped to open these doors.

Cliff Goldstein

Denver AMCON Show

Thu, 24 Apr 2014 11:15:00 GMT

Eclipse Engineering is excited to announce that we will have a booth at the upcoming Denver AMCON Show on May 13-14th 2014. AMCON is a national show circuit that targets Design & Contract Manufacturing. The show will take place at the Colorado Convention Center in downtown Denver and offers free admission and free parking! It is the first time Eclipse will have a booth at the Denver AMCON Show and we are excited to reach out to our customers, both new and long standing, to update everyone on our exciting capabilities here at Eclipse.

If you have any questions about the show, please feel free to call in to Eclipse and speak to your current sales staff member or you can also ask for Ryan and he would be happy to help you as well. You can also visit www.amconshows.com for information direct from AMCON.

Thank you for your interest and we look forward to seeing our guests at the show!

Eclipse Growth in 2013

Mon, 09 Dec 2013 15:22:00 GMT

It’s hard to believe that we moved into our building over 3.5 years ago! Since then, I don’t think we have taken time to slow down or rest one bit. Since we have moved, we have been upgrading our facility, moving into new spaces, knocking down walls, working on infrastructure, and buying machinery at a hurried pace. In that time, we have made improvements that you may or may not be aware of, but either way we would love to share these big changes from 2013 with you!

Large Diameter CNC – Most of you are aware of our ability to make sometimes ridiculously small parts, well this year we have added the ability to machine diameters up to 30 inches in house ! This control gives us even better opportunities to meet customer demands for pricing or expedites due to tighter control throughout the process.

CNC Milling – While technically, our CNC mill has been around a little over a year, in 2013 we really began our mastery of this process. Not only just used for “ 2nd Opp’s “, we are also turning plate to a fully finished part on this machine.

Variable Table Saw – To better facilitate our 2nd opp saw process for split machined rings and part notching, we built from scratch a 100% custom table saw capable of measurable cuts all the way down to .001″ .

Increased Square Footage – As mentioned previously, in just the last 2-3 years, we have increased our building size from 3700 sq feet to over 7300 sq feet! This new floor space has been used for new machines, better organization and the addition of manpower. In 2013 alone we have increased our manpower by 10% and actually doubling the number of staffed machinists!

AS9100 – In a previous blog we have discussed our ongoing process of becoming AS9100 certified as a manufacturing company. This has also lead to the creation of a full time Quality Control department beyond just “receiving” and the promotion of James Jaramillo to our Quality Control Supervisor and AS9100 Lead.

Manufacturing Software – Several years ago we moved to a new specialized manufacturing and inventory system. Through the years we have continued to plug more and more of our information into this software making it the focal part of our business. In addition to the behind the scenes work or moving our information to a new and more robust database system, increasing productivity and reliability, this year we have begun utilizing our software as the central point for all of our controlled document storage .

All of these are big projects that have really taken strides in 2013 and we would also like to remind everyone of a few other points. Because of the continued success we have had in your most demanding applications, we have really been plugging two of our custom blended compounds , EZ032 and EZ036. When other polymer solutions don’t provide the wear life you’re looking for, inquire with us about these specialty compounds.

As always, we will ask you: What are your needs ? What support do you require? Tired of being pitched “out of the box” solutions to your very custom engineering problems ?

Eclipse Engineering is ready to take your call and answer your questions.

Eclipse AS9100 Training

Fri, 16 Aug 2013 15:53:00 GMT

This wraps up a very exciting week here at Eclipse! On Tuesday, our management team spent the day with a trainer from our Manufacturing Software, Shoptech. On Wednesday, our production staff took their turn. The purpose of this training was to begin the implementation of an AS9100 Quality Management System here at Eclipse. We are obviously in the beginning phases, but I can assure you that Eclipse is moving full speed ahead in this endeavor and we are currently hoping to have our AS9100 certification within 6 – 9 months.

While we were not pushed into obtaining our AS9100 or ISO certification, we do realize that these requirements are held in very high regard with some of our customers. In addition to those customers who appreciate us going to this level of quality, we know without a doubt that this certification process will create a better company here at Eclipse which will benefit all of our customers immediately. This continual improvement here can now be monitored closely to ensure that we are taking every step possible to produce the highest quality products to our customer’s specifications.

If anyone has some immediate feedback, please don’t hesitate to share it with us! We look forward to this new system being in place and keep an eye out for updates on our progress!

Ryan Martin

Eclipse in Print

Tue, 23 Jul 2013 11:23:00 GMT

Thanks to our neighbors, Eclipse was given the opportunity to create our first ever print advertisement to be featured in the very first issue of Spirit of Flight Center Magazine. The Spirit of Flight Center is a local museum dedicated to the display of rare aviation artifacts. If you have a love for aviation and are in Colorado, it’s definitely something fun to see.

In our ad, we decided to feature a very simple image to outline exactly what we specialize in here at Eclipse. That focus was on custom designs for high tech applications, exactly to meet the needs of our customers. Hopefully you enjoy our ad, and don’t forget to stop by the museum and pick up your copy of the magazine!

Capseals, Kapseals, Hatseal’s Galore

Tue, 11 Dec 2012 17:26:00 GMT

No matter what you call it, Capseals, Kapseals, Hatseals, Eclipse can cross it over for you. Has your current seal supplier discontinued a product line that you depend on? Give Eclipse a call and we can cross these part numbers over to our Eclipse Seal Ring numbers for you. We have received many calls in the last few weeks from customers no longer able to get their hands on Minnesota Rubber Kin & Kex Kapseal “Boots”. With a quick conversation, we should be able to cross over these parts and facilitate a quick transition to the new seals. We would also be happy to work with the end user on any test data required to make this transition including material data tests, inspection, or PPAP documentation. Our engineers are currently in the process of creating catalog pages to facilitate standardized documentation for M.R., Trelleborg, & Parker cross references, but in the mean time please continue to contact us and we will continue to supply these on a part by part basis. Thank you for your interest in Eclipse.

Happy Halloween

Tue, 30 Oct 2012 11:57:00 GMT

As you can see below, we had loads of treats today at Eclipse. Everyone pitched in and brought food for lunch to celebrate the holiday week. Sloppy Joe’s, spaghetti salad, ghost brownies and yes, your eyes aren’t playing tricks on you, that is actually a “road kill” cake.

In addition to our monthly lunch meetings to discuss business, we absolutely love to have several pitch in lunches every year. My personal favorites tend to be when we pull out the grill and spend some time outside. Sometimes it’s the simple things at a company that mean the most and it’s no exception for these lunches. These days are fun little celebrations that bring a smile and laughter to everyone to give us a break from the norm and really bring us all together to have fun!

From everyone at Eclipse, be safe this week and don’t forget to treat yourself and your coworkers to some excitement and laughs!

Technology Upgrades

Mon, 22 Oct 2012 12:16:00 GMT

And the times they are a changin’

This morning we met with the construction crew running our new phone and internet lines and poles are going in the dirt today. Over the next week, ground construction will occur around our property to run business class lines that will support virtually unlimited phone growth for Eclipse as we move into the future. In addition to these telephone upgrades we will be gaining a 30X boost in our internet speeds! These changes are sorely needed and there are many new and exciting technology projects that we have on the horizon to help our productivity here and attempt to keep up with the ever growing world of technology. Of course the goal of these changes it to better serve our customers and make our employees more efficient and able to increase their workload both in and out of the office.

Today’s businesses are not only expected to be reachable at all times, but also productive. That will be one of the largest efforts we undertake with these new capabilities. With our ever increasing sales and traveling engineering staff, we are excited about the opportunity to keep these people out in the field more, while still having access to all of the information that they need when they’re away from the office.

We may not be the biggest name in the game, but we sure are growing and finding better ways to serve you, the customer. After all, shouldn’t that be what it’s all about?

Material Data Sheets

Thu, 04 Oct 2012 09:37:00 GMT

We have recently updated the Materials section of the website and Material Data Sheets are now online. You can now find descriptions of the most common materials used here at Eclipse. These may give you a great starting point when speaking with our engineering department about your specific application.

The Materials section will also be a great point of reference for standardized material test for our materials. You can use the website to download any material tests that you might need. If we have the report, then it’s online. So if you don’t see the one you need, please feel free to request it from engineering and we’ll track it down for you and add it to the site.

We will also continue to add new features and descriptions to the website so please feel free to check back in on us!

Eclipse Materials

Silicone Filled Spring Energized Seals

Mon, 17 Sep 2012 14:58:00 GMT

Filling a spring cavity with Silicone allows our customers to use a spring energized seal in environments where the media in the application does not come in contact with a metal spring.

There are many reasons to apply these this solution for various applications

1. Food Grade where we use an FDA Approved Silicone to cover the spring, and use a jacket material which is also FDA approved

2. When we are sealing a media that would hamper the ability of the spring to continue to be energized in the media. Media like an adhesive that will stop the spring from being active.

3. Filling a groove with Silicone where your goal is to have the least amount of fluid displacement for accurate positioning of a mechanical device.

There are several different types of Silicones depending on the usage. They can be for food grade use, high temperature, or by changing the viscosity they can act as a spring adding to the force of the existing spring.

Eclipse Spring Energized Seals

Wed, 12 Sep 2012 09:57:00 GMT

Eclipse Engineering began manufacturing Spring Energized seals in 2005

Today, we supply Spring Energized seals with ID’s as small as .065” to in excess of 3 feet or larger. We offer Cantilever, Canted Coil, Helical and Garter Spring energized designs.

This technology has allowed us to always offer the most appropriate solution to your sealing needs, regardless of the conditions or environment the seal will be operating. Through our broad range of utilized jacket materials we can seal virtually any media environment.

At Eclipse, we feel speed of response is a clear advantage to our customers. Eclipse can turn many prototype applications around with finished product in 2 weeks and in emergency situations, we can even shave the time down to a few days. We’re able to offer this service because we carry a wide array of raw materials, including our spring stock in Stainless, Hastelloy, and Elgiloy.

When the need arises, please call our engineering department to discuss your application.

Engineering Action Request Forms

Tue, 28 Aug 2012 11:50:00 GMT

When applications present themselves, very often there are details which are overlooked. Eclipse is now introducing our own Engineering Action Request form to get the details of your application in one neat form. Our engineering staff is always available to go over applications over the phone, however quite often, the information on this form can get the ball rolling and allow us to start the design for your application.

These forms have been added to our “Contact” tab with links for both a standard PDF that can be printed for your use, as well as an XLS template that you can tab through and check boxes right on your computer. Links will also be provided at the bottom of this post.

Once these forms are filled out, please feel free to email them directly to your rep, if you know who that is, or you can always email them to the sales@eclipseseal.com address or fax them to 303-635-3005.

We look forward to your new custom applications and thank you for thinking of Eclipse!

EAR – XLS Format

EAR – PDF Format

New Milling Capabilities at Eclipse

Thu, 23 Feb 2012 12:24:00 GMT

After turning away literally hundreds of requests for milled parts, we finally made the move to bring that manufacturing capability in house. Over the last ten years, we’ve taken on jobs that either had to be sent out to be milled or as a second operation, we used our manual mill to complete an operation on a part.

Thanks to our customers continued requests and the need for close tolerance parts from various grades of polymers, we purchased a new Haas VF-2 mill in December. Of course, along with the mill came more floor space, more tooling, more programming, more raw materials, more power, carts, toolboxes, measuring capability etc, etc, etc. Jason, our production manager, has inferred that in the case of a mill this list is inexhaustible.

We started manufacturing for our internal needs the end of January, and we are now ready to begin accepting RFQ’s for this type of business. The addition of the New Haas to the existing turning equipment extends your ability for product offerings to you or your customers. As your questions come up regarding what our capabilities are, please call sales or engineering.

We look forward to your continued support in this new product offering, and thank you for your support!

Best Wishes for a great 2012
Cliff

PTFE Increases

Thu, 03 Nov 2011 16:13:00 GMT

Dear Eclipse Customers:

Over the last 12 months, Eclipse has seen exponential increases in raw material costs used in supplying you with the quality parts that are expected from us.

Historical pricing for Virgin PTFE had remained fairly stable until July 2010 when it began a steady rise from $8.00/KG to $26.70/KG in July 2011. This represents over a 200% increase in a one year period. The graph pictured below shows glass and bronze filled PTFE along with Virgin PTFE depicting these trends. PTFE is traded as a commodity on a worldwide basis so while there may be spot buys at favorable pricing, overall pricing remains fairly consistent worldwide.

This kind of increase raises flags to those who see its immediate impact in their finished part pricing and has them asking why.

Flurospar is a mineral component required in the production of PTFE. There is currently a worldwide shortage of Fluorospar which has had a direct impact on PTFE pricing akin to an oil pipeline being shut down and seeing a near immediate increase in the cost of gasoline at the pump. The second factor is a bit more subtle. Pricing has been stable with little or no increase over the last 5-8 years. The industry had been absorbing some of these costs through a reduction in margin do to market tolerance. We believe there have been some opportunistic pricing that has been used to return margins back to previously sustained levels for the resin suppliers.

Relief for the rise in raw material cost can only come if the level of Fluorospar production is increased by opening new or dormant mines. We would be happy to provide the down hole seals.

PTFE is a material that is extremely difficult to replace because of the many favorable properties it exhibits. Few materials can match its broad range of uses and necessity because of the chemical resistance of its very slick properties. It has its niche and generally when you’re using it, there is a very good reason.

As a manufacture, the percentage of material cost in the piece price of a final part has risen substantially, while labor remains nearly unchanged. There may be added improvements in manufacturing to offset this increase however it is generally seen in the production of higher volume jobs while the middle to small volume customer bears the full brunt of this increase due to the percentage gain.

In the end, while we at Eclipse engineering have done everything in our power to absorb previous increases and find new ways to manufacture parts in a more effective manner, these increases in raw material costs will begin to make a bigger difference in the pricing of the final product, which unfortunately you have already begun to see. We do believe we may have seen a leveling off at this point and hope that some stability will return to this market. We continue to push for the most competitive pricing from our suppliers and do expect pricing to decrease as supplies rise and refill the supply chain.

For more information on this subject you can visit:

http://polyfluoroltd.blogspot.com/2011/04/whats-matter-with-ptfe-prices.html

PTFE increases in the gasket world

Thank you for your continued support.

Sincerely,

Cliff Goldstein

CEO

Early Expansion

Wed, 03 Nov 2010 14:27:00 GMT

Eclipse has only been in our new building since July and we’re already pleased to say that we’re expanding into another unit! A sudden vacancy in the unit above our office space is allowing us to take advantage of some much welcomed expansion. Currently, there are no “concrete” plans in place, however much of this […]

Eclipse Engineering “On the Move”

Fri, 09 Jul 2010 12:10:00 GMT

After 11 years in beautiful downtown Broomfield Colorado, Eclipse has finally moved to a permanent home.

Eclipse Engineering started out in an expansive 1750 Sq ft facility on Industrial Lane in 1999. At the time I thought of renting out some of the space as it seemed too big for our needs. In 2001, we purchased the soft seal side of Jemco Seal. Jemco was primarily a Colorado business and with that acquisition, we nearly doubled in size causing us to increase our floor space.

With our lease up, and the real estate market being what it was, we purchased a building in Erie, Colorado. We moved into a space a bit larger than before with the opportunity to expand 3 fold. The Building is located “in the country” with a great view of the Front Range Colorado Rockies. We also are located at the Erie Airport, so if you want to fly in to visit, you could taxi up to the back door.

Your support over the past 11 years has allowed us the opportunity to continue to grow and better serve you.

Like any move, it always looks a lot better after the fact. We are still in the throes of re-building and improving our infrastructure. I’m guessing another 5 months or so ought to get us moved in. Until then, it seems every day we move something else.

At the same time we are increasing the number of operations we perform in house, allowing us to better serve your immediate needs.

Eclipse has built its business on responsiveness to the market place. While we realize you have a choice in purchasing product, our goal is to make the decision a delightful experience working with us.

Thank you again for you support over the last decade.

New Website

Thu, 01 Jul 2010 13:22:00 GMT

Eclipse Engineering is proud to be displaying our new website. This will be a continual work in progress as we add function to the site and continue to make it more user friendly and include information that you can actually use.

We’re very excited to move this step forward and are happy to have some new style. There are many ideas floating around here to include technical data and engineering references to the site. Hopefully with some time, we will make this a site that you as a customer can use on a regular basis.

Please feel free to leave questions, comments, & suggestions for us to help make this a usable site.

Eclipse goes to Mars

Wed, 30 Jun 2010 14:07:00 GMT

When Spirit and Opportunity descended to the Martian surface, seals from Eclipse Engineering were on board. One set of seals protects the asmith drive assembly from the very fine dust particulate found on the Martian surface. These seals allow the camera mast to rotate 360 degrees. A second set of seals is located on the […]