A cryogenic valve is judged by one thing: how far the packing sits from the cold body. LNG at −162 °C will freeze any gland within a few hundred millimetres of the body, and a frozen gland cannot be tightened or operated. The extended bonnet moves the packing up the neck so it stays near ambient. Body in CF8M for LNG, LF2 for −46 °C and LF3 for −101 °C; bolted bonnet, rising stem, anti-extrusion seat rings on the cryogenic builds.
Size RangeNPS 1/2" – 8"
Pressure RatingClass 150 / 300 (Class 600 on request)
Design StandardASME B16.34 / BS 6364
Temperature Range−46 °C (LF2), −101 °C (LF3), −196 °C (CF8M)
BonnetExtended bonnet — packing kept near ambient
End ConnectionSocket weld (ASME B16.11), threaded (ASME B1.20.1), butt weld (ASME B16.25) or flanged (ASME B16.5)
StemRising stem, OS&Y
MediaLNG, liquid nitrogen, liquid oxygen, ethylene
Max. Working Temperature−46 °C to −196 °C
Body / BonnetASTM A352 LF2, LF3, or CF8M
DiscSolid wedge, cryogenic-treated
SeatIntegral or welded seat rings, anti-extrusion
PackingGraphite or PTFE, low-temperature
CleaningDegreased for oxygen service on request
