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.

by Brandon Pascual Brandon Pascual 5 Comments

Spring-Energized Seals: Technical Mastery in Challenging Applications

When it comes to critical industrial applications, the smallest component can make the biggest difference. Advanced EMC Technologies’ spring-energized seals are at the forefront of sealing technology, engineered to thrive in some of the harshest environments. Here, we delve into specific use cases that illustrate the technical challenges our seals overcome and the innovative design features that make them indispensable.

Tackling Extreme Pressure and Temperature in Oil and Gas Downhole Tools

In the oil and gas sector, downhole tools are subjected to pressures exceeding 30,000 psi and temperatures that can fluctuate drastically between the surface and deep subterranean environments. These tools must also contend with corrosive fracking fluids and abrasive particulates that can compromise seal integrity.

Advanced EMC Technologies developed a custom slantcoil spring design that maintains a consistent sealing force across a wide deflection range, crucial for ensuring reliability in dynamic pressure conditions. By integrating PTFE blends specifically formulated for high-pressure and high-temperature applications, these seals resist chemical attack and provide low friction, reducing wear and extending service life.

Our seals have been successfully deployed in deep-sea drilling operations, where they have demonstrated superior durability and reliability, minimizing downtime and maintenance costs. The ability to maintain seal integrity under such extreme conditions has solidified our reputation as a leader in sealing solutions for the oil and gas industry.

Ensuring Integrity in Aerospace Cryogenic Systems

Aerospace cryogenic systems, particularly those handling liquid oxygen, require seals that can perform at temperatures as low as -320°F without becoming brittle or losing elasticity. The challenge is compounded by the need to ensure that these seals do not outgas or introduce contaminants into ultra-clean environments.

Our cantilever beam spring seals, crafted from proprietary PTFE blends, offer the flexibility and resilience needed to maintain a tight seal at cryogenic temperatures. These seals are engineered to provide a constant sealing force, compensating for any thermal contraction or expansion of the surrounding hardware. Additionally, the materials used are selected for their low outgassing properties, ensuring that the stringent cleanliness requirements of aerospace applications are met.

In liquid oxygen systems, our seals have proven their ability to prevent leakage and maintain system integrity, even under the mechanical stresses encountered during aerospace operations. This reliability is critical not only for the performance of the systems but also for the safety of the personnel and equipment involved.

Enhancing Durability and Precision in Semiconductor Manufacturing

Semiconductor manufacturing involves the use of highly corrosive chemicals and demands seals that can function in ultra-clean environments without introducing contaminants. The seals must also withstand the rigors of high temperatures and fluctuating pressures during processes like chemical vapor deposition (CVD).

Advanced EMC Technologies’ helical spring seals are designed to provide a robust sealing solution that can endure the harsh chemical environments typical in semiconductor manufacturing. Our seals are made from specially formulated PTFE blends that offer exceptional chemical resistance and low friction, crucial for maintaining precision and reliability in CVD processes.

Our seals have been instrumental in enhancing the longevity and performance of semiconductor manufacturing equipment. By reducing the frequency of seal replacements and minimizing contamination risks, we have helped our clients achieve higher yields and improved process stability.

Delivering Precision and Reliability in Medical Devices

In the medical field, particularly in implantable devices like pumps and valves, seals must not only provide reliable performance over long periods but also be biocompatible and resistant to the sterilization processes required for medical-grade components.

Our slantcoil spring seals are specifically designed for medical applications, offering a gentle but effective sealing force that prevents fluid leakage in delicate, high-precision devices. These seals are manufactured from biocompatible materials that withstand repeated sterilization without degrading, ensuring long-term reliability.

In implantable medical pumps, our seals have demonstrated exceptional performance, maintaining their integrity and functionality over extended periods. This reliability is critical for patient safety and device efficacy, making our seals a trusted choice in the medical industry.

Conclusion

Advanced EMC Technologies’ spring-energized seals are more than just components—they are critical to the success of some of the most challenging industrial applications. By understanding the specific demands of each industry and application, we engineer solutions that not only meet but exceed expectations, providing reliability, durability, and peace of mind.

If you are facing a sealing challenge in your industry, reach out to our team to discover how our advanced sealing solutions can drive your success.

FAQs:

What makes spring-energized seals superior for extreme applications?
Spring-energized seals are designed to maintain a constant sealing force, even under extreme pressure, temperature, and chemical conditions, making them ideal for harsh environments.

How do spring-energized seals perform in cryogenic temperatures?
Spring-energized seals, especially those made from PTFE blends, retain their flexibility and sealing integrity at cryogenic temperatures, preventing leakage and maintaining performance.

What industries benefit most from spring-energized seals?
Industries such as oil and gas, aerospace, semiconductor manufacturing, and medical devices greatly benefit from the reliability and durability of spring-energized seals.

Can spring-energized seals be customized for specific applications?
Yes, Advanced EMC Technologies offers customization of spring-energized seals to meet the unique requirements of specific applications and industries.

What materials are used in spring-energized seals for chemical resistance?
Advanced EMC Technologies uses specially formulated PTFE blends and other high-performance materials to ensure chemical resistance and longevity in harsh environments.