Refrigerators

A multilayer microminiature refrigerator comprising a laminate of three planar-surfaced thin plates bonded pressure-tight at the interfaces between adjacent plates, means providing in one interface between two adjacent plates a first continuous inflow passage means extending from an inlet to a cooling chamber and including capillary passage means, means for connecting said inlet to a source of refrigerant gas at high pressure, means providing in the other interface between two adjacent plates a further continuous outflow passage menas leading to an outlet, and a passage interconnecting said chamber and said further passage means whereby fluid at reduced pressure from said cooling chamber may pass through said further passage means to said outlet in counterflow heat exchange relation with fluid in said first passage means for regenerative precooling, each of said passage means being of micron size whereby to promote laminar flow therein.

A microminiature cryogenic refrigerator for cooling superconductor and like devices comprising a plurality of members having substantially the same coefficient of thermal expansion, means bonding said members together over parallel interface areas to form a laminate and means forming in said laminate a low temperature chamber connected with input and output fluid ports by respective supply and return fluid lines in the form of channels in or on said members at said interface areas, said supply line comprising a first section for conducting incoming highly compressed gas and a serially connected capillary section whereby the high-pressure gas is allowed to expand and reduce in temperature before entering said chamber, means whereby said chamber may be in heat exchange contact with a device to be cooled, and said return line having a section extending substantially coextensively in heat exchange relation adjacent the first section of said supply line but in a different plane in one laminate, the interfaces between said members being sealed pressure-tight except for said surface channels and ports.

A microminiature cryogenic refrigerator for cooling superconductors and like devices comprising a plurality of members having substantially the same coefficient of thermal expansion, means bonding said members together over prallel interface areas to form a laminate, means forming a low temperature chamber in said laminate, means forming a fluid supply passage connecting the exterior of said refrigerator to said chamber, said passage including in series a heat exchanger section and a capillary section, return passage means for conducting fluid from said cooling chamber in heat exchange relation with the incoming fluid in said heat exchange section and additional passage means for conducting a portion of said incoming fluid in bypass relation to said cooling chamber and passing said fluid portion to the exterior of said refrigerator in heat exchange relation with the incoming fluid in said heat exchange section.