MIXED REFRIGERANT CRYOGENIC VAPOR COMPRESSION CYCLE

摘要

A closed cycle cryogenic refrigerating system (10) with a fixed restrictor (28) operates with a compressor inlet (22) pressure in a range of 0.1 Mpa and 2.5 Mpa. A basic cryogenic refrigerant mixture is used to which is added approximately 3 % to 25 % of helium, hydrogen and/or neon. A ratio of refrigerant density at the inlet of the fixed restrictor (28) between steady-state operation and operation at the beginning of cool-down is in an approximate range of 7 to 17. Relatively rapid cool-down is achieved and evaporator (3) temperature is maintained in an approximate range of 70K to 120K.