Astra Seals® – Cryogenic & Aerospace Sealing Solutions
Astra Seals® are advanced cryogenic sealing solutions engineered for use in the most demanding aerospace, defence, and industrial applications. Originally developed by an aerospace engineer, these high-performance seals are specifically designed to operate reliably in extreme low-temperature environments, including exposure to liquid oxygen, nitrogen, and hydrogen.
Unlike standard O-rings that become brittle and fail under cryogenic conditions, Astra Seals® maintain integrity and performance across a wide temperature range, making them a trusted choice for aerospace sealing applications and defence systems.
Created by an Aerospace Engineer to combat the harsh environments associated with liquid oxygen and the problems associated in sealing other cold media, such as liquid nitrogen and hydrogen, the Astra Seal® copes perfectly with the extreme low temperatures which make most O-Rings brittle, which in turn leads to failure.
Key Features & Benefits
- Extreme temperature resistance from -250°C to +260°C
- Designed for cryogenic sealing applications involving liquid gases
- PTFE (FEP/PFA) encapsulated O-ring design for chemical and thermal stability
- Internal stainless steel spring energiser for consistent sealing performance
- Proven reliability in space, aerospace, and defence environments
The Ashtons team has experience of working with businesses across a diverse range of industries which use cryogenic processes as part of their operation.
In these types of operations, a cryogenic gasket will be necessary in order to ensure that safe and reliable performance is achieved.
Why are specialist cryogenic seals necessary?
There are a number of reasons to choose a specialist seal over a standard seal in these types of low temperature operations. These include:
Protection of dangerous cryogenic fluids: Depending on the type being used, cryogenic liquids can burn, can cause asphyxiation and can be toxic. Some materials can be a risk of fire and explosion too, which makes suitable protection and containment an absolute necessity.
Conventional O-Rings may fail: In many cases, the working temperature of the application will be too low for standard O-Rings to function properly. Very cold temperatures can lead to some elastomers reaching a glass transition state (Tg), which causes it to become less flexible and more brittle, risking failure.
Contraction needs to be accounted for: Expansion and contraction which occurs naturally as temperatures change can cause O-Rings to become unseated, risking cracking, leaks and failure occurring.
Cold set must be avoided: In applications where cryogenic operations work alongside higher temperature operations, the risk of stresses on the O-Ring being unable to relax at low temperatures is high when the wrong type of seal is used. Known as ‘cold set’, this will create an unviable seal, leading to leakage and failure.
In cryogenic operations, the right choice of seal is crucial. The choice will depend on the operating temperature. For example, neoprene and nitrile may fail at temperatures below -40°C, and silicone and fluorosilicone by -100°C. Cryogenic operations are much lower even than this, so for operations working at extreme low temperatures, speak to our Technical Department on 01226 273700.
Astra Seals® are widely used across critical sealing environments where safety and reliability are essential. Typical applications include:
- Aerospace and defence systems
- Cryogenic processing and storage
- Chemical and energy industries
- Pharmaceutical and food-grade applications requiring high integrity sealing
These seals have been successfully deployed in space shuttle and rocket programmes, demonstrating their performance in mission-critical conditions.
Why Choose Astra Seals®?
When operating in extreme temperatures or hazardous environments, standard sealing materials are often insufficient. Astra Seals® provide a robust solution by combining PTFE encapsulation with spring-energised sealing technology, ensuring consistent performance where failure is not an option.
For industries requiring high-performance cryogenic seals in the UK, Astra Seals® offer a reliable, proven solution for maintaining system integrity and preventing leakage in the most challenging conditions.
For more information or to discuss your sealing requirements please contact our Technical Department via ask@ashton-group.co.uk or call 01226 273700.
FAQ's
1. What are Astra Seals®?
Astra Seals® are high-performance cryogenic seals designed for aerospace, defence, and industrial applications. They feature a PTFE encapsulated O-ring with a spring-energised core, providing reliable sealing in extreme temperature environments where standard seals may fail.
2. What are Astra Seals® used for?
Astra Seals® are used in aerospace and defence sealing applications, particularly where systems operate at cryogenic temperatures or involve liquid gases such as oxygen, nitrogen, and hydrogen. They are also used in energy, chemical processing, and high-spec industrial environments.
3. What temperature range can Astra Seals® operate in?
Astra Seals® are designed to perform in extreme temperatures, typically ranging from approximately -250°C to +260°C. This makes them ideal for cryogenic sealing applications as well as high-temperature industrial systems.
4. What makes Astra Seals® suitable for cryogenic applications?
Unlike conventional elastomer seals, Astra Seals® use a PTFE (FEP or PFA) encapsulation combined with a stainless steel spring energiser. This design maintains sealing force even at very low temperatures, preventing brittleness, shrinkage, and leakage in cryogenic environments.
5. Are Astra Seals® suitable for aerospace and defence use?
Yes. Astra Seals® are specifically engineered for aerospace sealing solutions and defence applications, where reliability and safety are critical. They have been used in demanding environments, including space and rocket systems, where performance cannot be compromised.