Selection of O-rings for cryogenic liquid pumps
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As the title suggests, how should one choose O-rings for cryogenic liquid pumps (such as those using liquid oxygen, nitrogen, or argon)? The O-rings I purchased started leaking shortly after installation – what material should such O-rings be made of?
Perfluoroethers are not resistant to low temperatures; PTFE can be used in such conditions. For temperatures that are not extremely low, Greene Tweed FVMQ rings can be considered, as they can withstand temperatures down to -60 degrees℃
The temperature of liquid argon is about -189 degrees Celsius, so FVMQ coils cannot be used. Tetrafluoride is relatively hard and difficult to install. Our pump is from Crostar; its original O-ring was made of rubber, and it worked fine for over 2 years without any problems. The issue is that we don’t know what material it’s made of!
Is the temperature at the location where the O-ring is placed as low as minus 189 degrees?
Liquid argon passes through this seal, so the temperature should also be minus 189 degrees Celsius.
As far as I know about O-ring materials, none can actually withstand such temperatures.
Well, would a metal O-ring (hollow) work?