Patent ID: 11530845

Abstract:
A cryogenic apparatus (10) includes an enclosure (12), a first thermo-mechanical cooler (20) and a second thermo-mechanical cooler (22) which project into the enclosure (12), at least the second thermo-mechanical cooler (22) being a two-stage cooler, and each cooler (20, 22) having a fluid inlet and a fluid outlet for each stage, and a helium gas extraction flow duct (40) which extends into the enclosure (12) and which communicates with a vessel (42) to contain liquid helium within the enclosure (12). There is a first heat exchanger (62) within the gas flow duct (40). A first duct (74) carries cold helium gas from a fluid outlet (73) of the first thermo-mechanical cooler (20) and through the first heat exchanger (62) to the fluid inlet (75) of the second stage of the second thermo-mechanical cooler (22).