Polymer Spring Energized Teflon Seals
by Daniel Mays Daniel Mays No Comments

Spring-Energized Seals for the Fluid Industry

Spring-energized seals have proven themselves indispensable in the fluid handling industry, alongside pumps, valves, fittings, and filtration. In fact, they serve as a precision technology to support key fluid handling systems. Canted coil springs enhance reliability, efficiency, and service life in fluid handling applications by providing precise force control, robust sealing, and long-term performance.

What Are Spring-Energized Seals? 

Spring-energized seals may look like ordinary polymer seals from the outside, but the difference lies within. A metallic spring is built into the seal, and its purpose is to maintain continuous contact between the sealing lip and the mating surface. That spring ensures the seal maintains the right amount of contact pressure, even when conditions fluctuate.

The design gives engineers a reliable way to handle problems that defeat traditional seals. Under pressure cycling, thermal changes, or material creep, ordinary seals can lose their ability to press tightly against surfaces. Once that happens, leaks are inevitable. With a spring-energized design, however, the spring compensates for those changes. It provides a consistent, repeatable load that keeps the sealing interface intact.

These seals are also highly versatile. Spring-energized seal jackets can be manufactured with advanced polymers such as PTFE, PEEK, or UHMW-PE. Engineering polymers such as this resist heat, wear, and chemicals. Combined with the spring element, they deliver performance that elastomeric seals or standard designs simply cannot match. The result is longer service life, reliable operation, and the ability to thrive in environments where ordinary seals fail.

In industries where precision is critical—fluid handling, aerospace, medical, and energy—spring-energized seals stand out as a proven choice. They bridge the gap between demanding operating conditions and the need for dependable, leak-free performance.

Why the Fluid Handling Industry Needs Advanced Spring Technology 

There are four key challenges in the fluid handling industry that can be addressed through the use of advanced spring-energized seal technology. These include large pressure fluctuations, exposure to aggressive chemicals, high cycling rates, and extreme temperature swings.

Large Pressure Fluctuations

When pressure inside a pump or valve spikes, a conventional elastomeric seal can lose preload. Eventually, they will deform, relax, and eventually fail to maintain a consistent sealing force. The result? Leaks and unpredictable system behavior. Spring-energized seals, by contrast, maintain nearly constant force across wide deflection ranges. Their unique geometry keeps seals energized and couplings secure, even when pressure swings from one extreme to the other.

Exposure to Aggressive Chemicals

Elastomers and some polymers will swell or crack when they encounter solvents, caustics, or sterilizing fluids. Once degradation sets in, seals fail quickly. Spring-energized seals solve that problem with corrosion-resistant alloys like stainless steel, Inconel, and Hastelloy. Pair canted coil springs with PTFE or PEEK seal jackets, and you have a system that resists attack and stays reliable, even in the harshest chemical environments.

High Cycling Rates

Pumps, valves, and quick disconnect couplings cycle millions of times in their lifetime. Standard seals suffer from fatigue, creep, and inconsistent force output long before those cycles are reached. That inconsistency leads to premature wear or outright leakage. Spring-energized seals are built differently. Their geometry spreads stresses evenly, allowing spring-energized seals to withstand high cycle counts while delivering the same force from start to finish.

Extreme Temperature Swings

Temperature changes wreak havoc on seals. Elastomers turn brittle in the cold, soften in the heat, and lose elasticity under cycling. Spring-energized polymer seals can continue to perform across cryogenic lows and elevated highs. Whether in sterilization cycles, hot fluid transport, or cryogenic handling, canted coil springs can keep seals energized and predictable.

The Takeaway

Every one of these challenges comes back to the same requirement: consistent, predictable seal force. Traditional approaches fall short, but spring energizers deliver the durability, adaptability, and precision needed to keep fluid handling systems running smoothly.

Applications in the Fluid Handling Industry

There are a host of applications for spring-energized seals in the fluid handling industry, starting with pumps and valves where they ensure long-lasting seals, both for static and dynamic applications. They are also very valuable in quick-connect/disconnect couplings, where they provide both secure retention and controlled release. In filtration systems, spring-energizers help to maintain seal integrity during pressure surges. These sealing solutions are also ideal for use with medical and pharmaceutical fluid handling, where there are FDA-compliant sealing solutions that can endure aggressive sterilization and cleaning processes. Finally, these seals are ideal for oil & gas fluid systems that operate under extreme temperatures and pressures in both topside and downhole equipment.

Conclusion

Robust, reliable sealing is absolutely necessary in fluid handling operations, regardless of the industry. Spring-energized seals for the fluid industry provide robust, reliable seals. They can address large pressure fluctuations, exposure to aggressive chemicals, high cycling rates, and extreme temperature changes. 

If you are designing a sealing solution for a fluid handling operation, contact us today at Advanced EMC to learn how spring-energized seals can positively impact the reliability and life of your system. Our engineers look forward to working with you.

Spring Energized PTFE Seal
by Daniel Mays Daniel Mays No Comments

Backup Rings in High-Pressure Sealing Systems: Preventing Seal Extrusion and Extending Service Life

Backup rings in high-pressure sealing systems address face extrusion failure in both dynamic and static seals found in high-pressure systems. Extrusion in sealing occurs when pressurized fluid forces the seal material into the clearance gap between mating surfaces, compromising seal performance. However, backup rings are a simple, low-cost (but critical) solution for extending the service life and maintaining the performance of extreme sealing conditions.

The Challenge of Seal Extrusion in High-Pressure Applications

Seal extrusion happens when pressurized fluid forces part of a sealing element into the clearance gap between mating hardware surfaces. Under high pressure, the soft material deforms plastically and begins to “flow” into this gap, where it can be pinched, torn, or permanently deformed. The result from seal extrusion is nibbling damage along the edges, rapid loss of sealing capability, and, in severe cases, catastrophic leakage.

Extrusion not only shortens seal life but also accelerates equipment wear, drives unplanned downtime, and raises operating costs in hydraulic, pneumatic, and process systems. The causes of seal extrusion are typically high pressure differentials ( > 1500 psi) and/or significant clearance gaps, exacerbated by the use of elastomers or polymers that deform plastically under a load. Seal extrusion can be difficult to avoid under certain circumstances, but that is where backup rings come in.

Backup Rings in High-Pressure Sealing Systems: Purpose and Function

Backup rings in high-pressure sealing systems are annular support components that are installed next to a seal, such as an O-ring or a spring-energized seal. They act as an effective barrier to keep the seal from being forced into the clearance gap.

Backup rings come in different configurations, including single-ring, double-ring (for applications with bi-directional pressure), as well as split vs solid rings. Regardless of the configuration chosen, it is critical to achieve a precise fit because too loose undermines support, while too tight causes problems with assembly.

Material Considerations for Backup Rings in High-Pressure Sealing Systems

The three most commonly used materials for backup rings are PTFE, PEEK, and Nylon. However, other materials such as  UHMW-PE, filled PTFE blends for wear resistance, reinforced polymers for high PV limits, may be used.

PTFE

PTFE is an excellent option for backup rings with its extremely low coefficient of friction and extensive chemical compatibility. It works exceptionally well for applications requiring dynamic sealing or very low temperatures. Its primary limitations are the possibility of cold flow under sustained loads, so it might not always be suitable for extreme pressure conditions.

PEEK

PEEK is another good option for use as a backup ring with its high mechanical strength and excellent resistance to extrusion, as well as its thermal stability up to ~250°C. It also possesses exceptional resistance to extrusion. While it may be a more costly option compared to other polymers, it has found widespread application in industries such as aerospace, oil and gas, and high-performance hydraulics.

Nylon (PA)

Nylon works extremely well in moderate conditions with its strength, and it has a more economical price compared to PEEK and PTFE. However, it does have some critical limitations that including swelling and water absorption, both of which can heavily impact tolerances.

Design and Geometry Options

Solid backup rings provide the best extrusion resistance but can be challenging to install. Split rings can simplify the assembly process, but may allowed extrusion under extremely high loads, which essential defeats the purpose of having a backup ring. Another alternative is the use of spiral cut designs, which balance easier installation (without requiring excessive stretching) with maintaining good support for the seal. Contoured cuts such as scarf of step joints further reduce weak points found at splits.

For pressure direction, a single ring works when the load comes from one side, while double rings are necessary for bidirectional pressure. In every case, the trade-off is clear: easier installation often means slightly higher extrusion risk at the joint.

Engineering Considerations for Integration

Housing tolerances are critical for backup rings. Excessive clearance gaps increase the risk of extrusion, while precise fits provide reliable support. Single rings work well when pressure comes from one direction. However, double rings are required when it fluctuates or is bidirectional. Temperature adds another layer of complexity. Heat accelerates creep and changes dimensions through thermal expansion, which weakens long-term performance. Material compatibility is also important. Chemicals, lubricants, or swelling agents can reduce hardness and shorten service life. In failure analysis, extrusion often appears as edge nibbling or shearing. Compression set, on the other hand, leaves the ring permanently deformed. Recognizing the difference is key to preventing repeat issues.

Conclusion

Backup rings extend seal service life by preventing premature failure and protecting against extrusion. They reduce downtime and maintenance costs, which is especially valuable in high-value systems. Reliability and safety improve in critical applications where failures aren’t an option. They also make it possible to use softer elastomers for better sealing performance without increasing the risk of extrusion.

Investing in the right backup ring extends seal life, reduces failures, and ultimately saves money and downtime. Contact us at Advanced EMC to learn more about backup ring solutions.