Cryogenic valves leak there are two main cases, one internal leakage; the second is leakage.
Valve internal leakage mainly due to deformation of the seal-produced at low temperatures. When the medium temperature dropped to produce the material phase transition caused by volume change, so the original high precision grinding sealing surface warpage caused by low temperature sealing bad.
Leakage of the valve: one is the valve and pipe flange connections, because connections litter, connecting bolts, and connections between the low temperature shrink material is not synchronized to produce relaxation and lead to leaks. So can the body and pipeline connections to the flange welded structure, to avoid the low leakage. The second is leakage at the stem and packing.
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