Severe Cryogenic Cycling LNG Service
Severe Cryogenic Cycling LNG Service
(OP)
I need some help. My company manufactures LNG fuel dispensers. The service is fairly severe as temperature fluctuates between ambient and -220°F. Think car pulls up, activates system, system goes cryo, car pulls away, system slowly returns to ambient. We have swing checks in the return line that have started to leak from the cap to body connection. Originally, they were supplied with a TFE sheet gasket and B8 class I bolting. After the problems, we discussed the issue with a gasket manufacturer and they advised us to use a Gylon material and upgrade the bolting to class II. We are uncertain if this will work. Does anyone out there have experience in severe cycling cryogenic service? Any help would be much appreciated.





RE: Severe Cryogenic Cycling LNG Service
Some pictures might help too...
One solution is to add belleville washers. They should be sized so that they just come flat when the proper bolt torque is applied.
A much better solution is to use cryogenic check valves that have no body seals. You'll find a few poppet style valves where the poppet is actually inserted into the body through one of the ports. That eliminates a body seal altogether. Pipe threaded ends are common and work well. Take a look at Generant and Check All Valve.
http://www.generant.com/
http://www.checkall.com/
RE: Severe Cryogenic Cycling LNG Service