O-rings for cryogenic applications – sealing even in extremely low temperatures

In cryogenic environments, when the temperature drops to extremely low values, ordinary seals become brittle, lose elasticity, and can crack. The risk of permanent deformation also increases, leading to leaks. Standard materials used for the production of sealing rings are often not chemically compatible with the aggressive environment of cryogenic media, such as oxygen, nitrogen, helium, methane, argon.

In cryogenic conditions, where the temperature drops below -150° C, at Power Rubber we recommend solutions such as PTFE O-rings (pure or filled), seamless FEP/PFA encapsulated O-rings, and spring-energized seals.

Cryogenics and challenges associated with very low temperatures

Cryogenics is a field of science and technology that involves, among other things, studying the properties of materials at extremely low temperatures, which affect the change of their chemical properties. In industries such as pharmaceuticals, aviation, or the oil and gas industry, temperatures below -150°C (e.g., in the case of liquid nitrogen, helium, or methane) are commonplace. Cryogenic seals must maintain full tightness to prevent leaks, failures, or even explosions.

Behavior of seals in extreme cold conditions

Elastomers exposed to cryogenic temperatures can shrink, harden, and become brittle, which worsens their sealing properties. Standard testing methods (e.g., ASTM D2137, D1329, D395) allow evaluating the material's resistance to cracking, elasticity, and permanent deformation.

Recommended materials for cryogenic applications

• PTFE O-rings (pure or filled) – characterized by chemical resistance, low friction coefficient, and operate up to temperatures of -200°C. Ideal for laboratory and aviation applications.

• FEP/PFA coated O-rings – have a flexible core (e.g., Viton® or silicone) and a seamless cover. FEP withstands temperatures from -60°C to +205°C, PFA up to +260°C. They are highly chemically resistant, elastic, and ideal for static applications with cryogenic liquids.

• Spring-energized seals – resistant to temperatures even down to -250°C, used in the most demanding applications.

Typical applications of cryogenic seals

• Space technology: cryogenic valves, fuel tanks

• Oil and gas industry: LNG/GPL transport and storage

• Medicine and scientific research: MRI machines, pumping systems, special gases, astronomical devices

FEP spring-energized O-rings - advanced cryogenic seals 

To ensure complete sealing in cryogenic conditions where the temperature drops even below -249°C, specially designed FEP spring-energized O-rings with a fluoropolymer casing, a material resistant to cracking and hardening at very low temperatures (down to about -250°C), were developed. Inside the seal is a spiral spring - an internal core made of stainless steel 302, designed to maintain constant pressure regardless of material shrinkage in extreme cold.

Compared to polymer rings, fluoropolymer seals retain integrity and elasticity down to -250°C. They do not undergo deformations caused by cold flow, ensuring reliability and operational stability in cryogenic conditions. Thanks to the spiral spring, the seal maintains constant compression and prevents leaks.

Benefits of using seamless FEP encapsulated O-rings

The use of seamless FEP encapsulated O-rings with an active spring ensures the reliability of systems operating in environments with extremely low temperatures. Thanks to the spring, they maintain constant sealing force throughout the cycle, minimizing the risk of undesired leaks. The specially developed design of FEP spring-energized O-rings eliminates deformations in low temperatures, significantly extending the seal's lifespan and reducing the need for frequent replacements. As a result, processes requiring the highest integrity, such as vaccine lyophilization or biological material storage, gain a higher level of safety and operational stability.

High-performance cryogenic seals in the production of lyophilized allergy vaccines

The production of lyophilized anti-allergy vaccines takes place at a temperature of -200°C. In cryogenic conditions, standard elastomeric seals become brittle, lose elasticity, do not maintain constant compressive pressure during long static freezing cycles, which poses the risk of leaks and product quality deterioration. The use of FEP encapsulated spring-energized O-rings eliminates the risk of deformation caused by cold flow, allowing for constant sealing integrity even during long cryogenic cycles, which impacts the safety and quality of vaccine production.

What to consider when choosing O-rings for cryogenic applications

When using O-rings in a cryogenic environment, consider:

• The lowest possible leak rate (even on a micro scale)

• Clean and protective packaging

• Ease of installation at low forces - an advantage over metal seals

Where to buy O-rings for cryogenic applications?

At Power Rubber, we offer high-performance O-rings for cryogenic applications, perfectly suited for the production of lyophilized anti-allergy vaccines, biological material storage, or installations in the chemical and petrochemical industries. Our seals are designed to operate at temperatures reaching up to -249°C.

Our specialists will help you select the appropriate sealing solution for your cryogenic application.

Contact us for personalized advice!

Feel free to contact us at  +48 22 292 40 24 or +48 505 16 03 03, or by email (Power|PowerRubber.com| style="background-color: rgb(255, 255, 255); color: rgb(0, 91, 171); border-bottom: 1px dotted rgb(0, 91, 171); text-align: justify;"|Power|PowerRubber.com) or through our contact form.