CryoPacific, Inc.

United States

CryoPacific’s Cryogenic vacuum jacketed manual valves have excellent flow characteristics and are built to provide extremely low heat leak. These valves combine to have low thermal mass and high structural integrity for efficient operation at cryogenic temperatures. The bonnet extension member is long, thin walled, and precision machined to limit the conductive heat transfer. CPI valves are specifically designed for critical LH2 and LHe service where low heat leak is of the utmost importance. A dual aligned stem seal located in the extended valve bonnet assembly helps minimize the cold transference to the warm packing section which yields long packing and soft seal life. The valve head has a spring loaded swivel stabilizer design to prevent valve seat damage while seating. All moving and contacting parts have closely held tolerances for effective operation. The valve stem has thermal spacers that have a tight clearance to the barrel housing which allows for creation of a gas pocket. This feature allows the valve to be mounted in various angles off of the horizontal. The valve body has a port to provide for purging or a thermal relief connection source. All valves are Mass-spectrometer leak checked, proof pressure tested, and positive seating inspected for bubble tight shut-off. All of these features provides for the most reliable valve operation in the industry.

CPI bayonets are of state of the art design incorporating dissimilar metal technology which uses an Invar cylindrical nose piece and a stainless steel sleeve . These materials at cryogenic temperature react very differently to create a positive cold seal. Invar, having an extremely low coefficient of thermal contraction has virtually the same dimensional characteristics at cryogenic temperatures as within an ambient environment. The stainless steel sleeve will substantially shrink while exposed to cryogenic temperatures. This material combination, designed within a very close diametrical clearance tolerance, creates the most effective cryogenic cold seal . CPI bayonets have a long, extended cold transference path, via close tolerance mating parts, creates an effective gas pocket seal. The secondary atmospheric seal is an O-ring face flange seal. The gas pocket warms as the male and female flanges meet , resulting in an effective thermal design. All of these features results in CPI bayonets being very efficient and having very low heat leak values.