Vessel evacuation appts. using cryogenic pump - has gas molecule trap plate connected to vessel by double walled cooled nozzle

摘要

The equipment evacuates a vessel using a cryogenic pump with a refrigerated plate for trapping molecules of gas. This plate (3) is connected to the vessel (1) by a double-walled nozzle (5) joined to the latter and cooled by the circulation of liquid nitrogen or other suitable medium. The plate is mounted outside the nozzle and opposite and set back from an opening in the side of it. Dimensions are such that radiation reaching the plate emanates principally if not entirely from the cooled interior wall of the connecting nozzle. The axis of the housing assommodating the plate can be at right angles to that of the nozzle, and the housing can have an internal cooled wall.