There are several twists and turns in the road to getting installation of components for vacuum jacketed applications “right.”
To unravel some of these mysteries and to help reduce frustration over placement and location, Cryocomp has developed detailed instructions for various components used in vacuum jacket piping and cold box applications. Cryocomp is a DLH Industries’ product line of cryogenic and high vacuum valves.
Vacuum Seal-Off Valves must be installed no closer than 6” to 8” from a jacket termination or any other cold location (Figure 1). The vacuum seal-off valves have O-ring seals and with excessively low temperature, they will shrink and allow leakage into the vacuum space. It is also good practice to install the vacuum seal-off valve somewhere near the center of the vacuum mass. Orientation on the pipe is not critical, but to assure future servicing of the vacuum, the vacuum seal-off valve should be in a location that will allow a valve operator to be installed after the pipe is in service (Figure 2).
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