To be honest: Try to avoid any lubricants at ALL! Most of that Krytox
stuff gets rock solid at -200°. Use materials like PTFE or PCTFE which
have acceptable tribological properties at this temperature without
lubs. Try to keep the bearing out of the cryo temps, then you can
lubricate them. For example a long stem which can be heated.
In our LOX-valves (Ball) we ended up with PCTFE seals which were spring
loaded and pressure compensated. Bearings for the stem were outside the
cryo region and were heated.
Keep in mind, that those seals shrink at low temperatures and a LOX
valve can get stuck or at least needs significant more torque to operate
than under room temperature.
Cheers Bruno
"At that time [1909] the chief engineer was almost always the chief test pilot as
well. That had the fortunate result of eliminating poor engineering early in
aviation" (Igor Sikorsky)
--
Bruno Berger
IBB.ch engineering GmbH (LLC)
E-Mail: bruno.berger@xxxxxx
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Am 19.02.23 um 18:35 schrieb Rocket Pavitra:
What are the different options for lubricants to use for valves that carry cryogenic fluids (liquid oxygen/methane).
I searched online and can't seem to find one that can work well below -112 degree celsius.
Since Liquid oxygen is -183 and liquid nitrogen -210 there must be some sort of lubricant that is used in valves that operate with cryo fluids.
- Pavitra