PEEK is one of the most radiation resistant plastics in common use. It can withstand exposure of 109 rad before any performance degradation occurs. PEEK can also operate successfully at temperatures up to 500 ° F.

PEEK is usually used for back-up rings, bearings, and structural seal components such as seal carriers and valve blocks.

It's a challenge to create a spring energized seal jacket out of PEEK that could still flex and compile enough to generate an effective seal.

A very thin sealing lip is easy to bend, but this would also affect the wear life and pressure handling ability, especially at high temperature. On the other hand, a sealing lip that was too thick would not allow the spring to function properly or provide energy in the correct area.

JST's design engineers have established a perfect balance between flexible lip thickness and robust design. Comparatively speaking, the resultant lip thickness was very thin when sized against a typical PTFE lip design.

Any material fillers would further degrade PEEK's elongation properties. JST also upgraded the cantilever V-Spring material to Elgiloy® for improved performance in the stiff jacket, as well as greater corrosion resistance.