Method and apparatus for detecting a loss of differential pressure in a cryogenic refrigerator

摘要

A method for detecting the absence of a pressure differential across a cryogenic refrigerator includes the following steps. At least one measurement of load in the refrigerator is taken during both a warmstroke and a coldstroke of a refrigeration cycle. These measurements are then compared to determine whether the differential load across the cryogenic refrigerator has been lost. A system for performing this method includes a compressor that circulates compressed gas through a compressed gas line routed through a cryogenic refrigerator. Within the refrigerator, a displacer is driven through a refrigeration cycle by a motor. A means for measuring the load on the motor is provided, and an electronic module monitors the load measurements to detect a loss of differential pressure across the refrigerator by comparing the load on the motor during the warmstroke to the load on the motor during the coldstroke.