Small Diameter Spring Energized Seals
by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

How Spring Selection Defines Spring-Energized Seal Performance

Most failures blamed on PTFE actually originate in the spring. This blog post discusses the load-management system and key features of spring-energized seals for canted coil springs, V springs, cantilever springs, helical springs, and coil springs.

Canted Coil Springs (Slant Coil Springs)

Canted Coil Springs and Slant Coil Springs from Advanced EMC Technologies

These springs are wound so that individual coils are set at an angle to the longitudinal axis. They are highly versatile and often used for dynamic sealing applications. Their key feature of canted coil springs is the flat load curve they provide. These spring energizers generate a nearly constant force across a wide deflection range. The constant force allows precise control over friction and torque, making these spring energizers ideal for applications where these factors are critical. Canted coil springs are also unlikely to experience compression set.

Canted coil spring energizers work best in moderate to high-speed rotary applications. Beyond sealing, their unique design allows them to serve as mechanical connectors (latching/locking), EMI/RF shields, and multi-point electrical conductors.

V Springs (V Ribbon Springs)

The V spring is a general-purpose, cantilever-type energizer. They offer an excellent balance of performance and cost-effectiveness. In addition, V springs provide a moderate load over a wide deflection range. They function well in both static and dynamic applications, including those involving rotary or reciprocating motion.

V springs are frequently recommended for severe service conditions, including vacuum pressures and cryogenic temperatures. V spring energizers are often a preferred choice for harsh operating environments.

Cantilever Springs (Finger Springs)

Often referred to as finger springs, these spring energizers feature a V-shaped cross-section and are distinguished by a linear load curve, meaning the force increases linearly with deflection.

The load is concentrated at the very front edge of the seal lip, which provides positive wiping action and makes them particularly effective for exclusion and scraping applications. They also generate extremely low friction.

Cantilever spring energizers are well-suited for sealing viscous media. They are typically found in low to medium-speed applications, such as hydraulic cylinders, pumps, compressors, and shocks.

Helical Springs (Helical Flat / Compression Springs)

Helical springs consist of a wound ribbon of metal and are characterized by a high load-versus-displacement curve. Because they produce a very high unit load with a small deflection range, helical springs provide tight, reliable sealing. They are well-adapted for sealing light gases and liquids.

Helical springs are generally limited to static, slow-dynamic, or intermittently dynamic applications because friction and wear are less of a concern than seal reliability. These spring energizers are often used in pipe flanges and crush jackets where the seal must embed into surface irregularities. Experts highly recommend helical configurations for cryogenic applications.

Coil Springs (Spiral Pitch Springs)

When many people visualize a spring-energized seal, they picture this wire coil type. These spring-energizers actually perform best in high-pressure, medium-speed applications and are known for their low friction. 

Spring Materials

The performance of spring-energizers is also dependent on the material selection. The material selection is primarily determined by the chemical and thermal environments involved. At Advanced EMC, we recommend one of the following spring materials: 

  • Stainless Steel (300 Series, 17-7 PH, 301/304): Common for general-purpose and cryogenic applications
  • Hastelloy: Recommended for highly corrosive media
  • Elgiloy: Used for high heat, corrosive environments, and salt water
  • Inconel: Used in severe environments and cryogenic applications

Conclusion

When spring-energized seals fail, the problem is often not the jacket, but the spring. Knowing about load consistency, deflection behavior, and how that force is delivered over time is key to deflection, friction, wear, and whether a seal actually survives its operating environment.

At Advanced EMC, spring-energized seals are engineered as complete systems, not just components. Our team will assist you from spring selection to geometry and material pairing, aligning the seal design with real-world conditions. If you are troubleshooting a failure or designing for demanding service, contact Advanced EMC today.

Polymer Spring Energized Teflon Seals
by Sara McCaslin, PhD Sara McCaslin, PhD 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.