Patent ID: 8695357

Claim:
A pressure control system comprising: a storage tank defining a cryogen space for storing a liquefied gas and vapor at cryogenic temperatures; a first conduit through which the liquefied gas can be delivered to a use device, the first conduit connecting a lower portion of the cryogen space to the use device; a heater that is operable to vaporize the liquefied gas before it is delivered to the use device, the heater being disposed on the first conduit upstream from the use device; a first flow controller disposed on the first conduit downstream from the heater; a second conduit through which vapor can be delivered to the use device, the second conduit connecting a vapor space inside the cryogen space to the use device; a second flow controller disposed on the second conduit, a pressure sensor to measure the pressure inside the cryogen space, and a controller programmed to actuate both first and second flow controllers responsive to pressure measurements by the pressure sensor to maintain the pressure inside the cryogen space between predetermined values.