Patent ID: 6615591
Filing Date: 2003-09-09
Classification: F25B

Abstract:
A cryogenic refrigeration system, comprising:a compressor; a JT refrigerator including a JT valve through which a high pressure refrigerant gas discharged from the compressor is subjected to a Joule-Thomson expansion, and a refrigerant tank for storing the refrigerant, which has been liquefied by the Joule-Thomson expansion; a first heat exchanger, including a high pressure side passageway through which the high pressure refrigerant gas discharged from the compressor is passed and a low pressure side passageway through which a low pressure refrigerant gas from the refrigerant tank is passed, for exchanging heat between the high pressure refrigerant gas in the high pressure side passageway and the low pressure refrigerant gas in the low pressure side passageway; a pre-cooling refrigerator for pre-cooling the high pressure refrigerant gas, which has been cooled through the first heat exchanger, before the expansion through the JT valve; a first switching valve provided on an outlet side of the low pressure side passageway of the first heat exchanger; and a gas refrigerant collecting pipe including a second switching valve therealong and connecting the refrigerant tank with a pipe on a suction side of the compressor, wherein a clog elimination operation is performed, during which the JT valve is opened while the first switching valve is closed and the second switching valve is opened so that the refrigerant discharged from the compressor is passed at least through the high pressure side passageway of the first heat exchanger and the JT valve into the refrigerant tank while the refrigerant gas in the refrigerant tank is collected through the gas refrigerant collecting pipe.