Astra seals are a unique seal developed for extreme temperatures to provide sealing in high-pressure environments. This is a pressure sealing solution developed and manufactured by NES and there is really no better sealing option for cryogenic application.

NES’ Astra seals have been successfully used in a number of space shuttle and rocket launches, our Astra seals are favoured by leading manufacturers like Boeing, NASA and Lockheed.

Extended rigorous testing in harsh environments has shown that the NES Astra Seal outperforms FFKM for compression sets.

Created by an Aerospace Engineer to combat the harsh environments associated with liquid oxygen and the problems associated with sealing other cold media, such as liquid nitrogen and hydrogen, the Astra Seal copes perfectly with the extremely low temperatures which make most O Rings brittle, which in turn leads to failure.

Astra Seals are composed of multiple elements all of which are selected to perform perfectly in extremely low temperatures. One of the primary applications of our Astra Seals is within the space sector, where materials that perform in extremely low, cryogenic temperatures are essential to maintaining the functionality of space crafts, shuttles and rockets. Proper materials and sealing are extremely essential within the space sector for safety foremost but also tyo avoid wasting money as faulty products can be extremely costly for space launches.

Below is a breakdown of the different seals which are generally utilised for cryogenic application. The attributes required of seals for cold temperatures are evident and therefore temperature resistance is absolutely paramount but not the only requirement.

What is required of seals for cryogenic application?

Cryogenic refers to extremely cold temperatures. Considering this, materials for seals are required to be functional under extremely low temperatures. There are many seals out there that claim to be able to withstand low temperatures and, while this may be true in part, most of them are too brittle to withstand cryogenic levels and are simply developed for colder-than-average applications.

Astra Seals from NES are developed to deal with elements like liquid oxygen, liquid nitrogen and hydrogen and maintain functionality.

Why Astra Seals are superior

NES’ Astra Seals are a type of O-Ring but Astra Seals differ greatly where it counts, when it comes to extreme temperatures.

Traditional O-Rings turn brittle when faced with truly extreme low temperatures, while Astra Seals are developed to mitigate the risk presented by cryogenic temperatures. The Astra Seal is comprised of 302 strainless flat-wound ribbon spring which is then encased in either FEP or PFA jacketing to form the O-Ring. FEP performs in temperatures between -250°C to 204°C (-420°F to + 428°F) and PFA functions in temperatures between -250°C to 260°C (-420°F to + 500°F).

Astra Seals come in a number of sizes so they can be adapted for a number of fittings for a variety of different mechanical elements. This size adaptability perfectly suits their ability to adapt to extremely low temperatures alongside the material variations mentioned above.