Patent ID: 6041608
Filing Date: 2000-03-28
Classification: F25B

Abstract:
A cryogenic refrigerating apparatus comprising: a compressor unit (101, 201, 301) which is installed outside a room and has a compressor (11) and a first air-cooling heat exchanger (12) provided in communication with a discharge side piping (21) of the compressor (11); an intermediate unit (103, 203, 303) which is installed inside the room and has a gas supply piping (41) connected to the discharge side piping (21) of the compressor (11) and a second air-cooling heat exchanger (31) which is provided in communication with the gas supply piping (41) and cools helium gas through heat exchange with indoor air; and a cryogenic expander (5) connected to the gas supply piping (41); and characterized by comprising:a fan (33) for cooling the second air-cooling heat exchanger (31) of the intermediate unit (103, 203, 303); anda controller (6, 206, 306) having an intermediate unit air flow control section (6a, 206a, 306a) which controls air flow of the fan (33) to an increasing side under a condition that a temperature of gas supplied to the cryogenic expander (5) is not lower than a temperature at which a refrigerating capacity starts to reduce due to a temperature rise and controls the air flow of the fan (33) to a decreasing side under a condition that the temperature of the gas supplied to the cryogenic expander (5) is lower than the temperature at which the refrigerating capacity starts to reduce due to the temperature rise.