Oil-lubricated cryocooler compressor and operation method thereof

Abstract

An oil-lubricated cryocooler compressor that compresses a refrigerant gas of a cryocooler includes a liquid-cooled heat exchanger that cools the refrigerant gas and/or an oil through heat exchange with a coolant and a cooling controller that is configured to acquire a supply temperature of the coolant supplied to the liquid-cooled heat exchanger and to control a flow rate of the coolant of the liquid-cooled heat exchanger and/or an exhaust heat amount of the cryocooler compressor based on the acquired supply temperature of the coolant.

What is claimed is: 
     
         1 . An oil-lubricated cryocooler compressor that compresses a refrigerant gas of a cryocooler, the cryocooler compressor comprising:
 a liquid-cooled heat exchanger that cools the refrigerant gas and/or an oil through heat exchange with a coolant; and   a cooling controller that is configured to acquire a supply temperature of the coolant supplied to the liquid-cooled heat exchanger and to control a flow rate of the coolant of the liquid-cooled heat exchanger and/or an exhaust heat amount of the cryocooler compressor based on the acquired supply temperature of the coolant.   
     
     
         2 . The cryocooler compressor according to  claim 1 ,
 wherein the cooling controller is configured to compare the acquired supply temperature of the coolant with a temperature threshold value and to limit the flow rate of the coolant of the liquid-cooled heat exchanger when the supply temperature exceeds the temperature threshold value.   
     
     
         3 . The cryocooler compressor according to  claim 2 ,
 wherein the cooling controller comprises:
 a control valve that is connected in series with the liquid-cooled heat exchanger, and 
 a valve controller that is configured to close the control valve or to decrease an opening degree of the control valve when the supply temperature of the coolant exceeds the temperature threshold value. 
   
     
     
         4 . The cryocooler compressor according to  claim 2 ,
 wherein the cooling controller comprises:
 a bypass valve that is connected in parallel with the liquid-cooled heat exchanger, and 
 a valve controller that is configured to open the bypass valve or to increase an opening degree of the bypass valve when the supply temperature of the coolant exceeds the temperature threshold value. 
   
     
     
         5 . The cryocooler compressor according to  claim 2 , further comprising:
 an air-cooled heat exchanger that cools the refrigerant gas and/or the oil,   wherein the cooling controller is configured to operate the air-cooled heat exchanger when the supply temperature exceeds the temperature threshold value.   
     
     
         6 . The cryocooler compressor according to  claim 5 ,
 wherein the cooling controller is configured to acquire an ambient temperature and to stop the air-cooled heat exchanger and/or to release a limitation of the flow rate of the coolant based on the acquired ambient temperature.   
     
     
         7 . The cryocooler compressor according to  claim 1 ,
 wherein the cooling controller is configured to:
 acquire a discharge temperature of the coolant discharged from the liquid-cooled heat exchanger and the flow rate of the coolant of the liquid-cooled heat exchanger, 
 calculate an amount of heat dissipation to the liquid-cooled heat exchanger based on the acquired supply temperature, the acquired discharge temperature, and the acquired flow rate of the coolant, and 
 limit the flow rate of the coolant of the liquid-cooled heat exchanger such that the calculated amount of heat dissipation is equal to or smaller than an allowable amount of heat dissipation. 
   
     
     
         8 . The cryocooler compressor according to  claim 1 , further comprising:
 a compressor main body that compresses the refrigerant gas; and   a compressor motor that drives the compressor main body and that has a variable operation frequency,   wherein the cooling controller is configured to compare the acquired supply temperature of the coolant with a temperature threshold value and to limit the operation frequency of the compressor motor when the supply temperature exceeds the temperature threshold value.   
     
     
         9 . An operation method of an oil-lubricated cryocooler compressor that compresses a refrigerant gas of a cryocooler, the cryocooler compressor including a liquid-cooled heat exchanger that cools the refrigerant gas and/or an oil through heat exchange with a coolant, the method comprising:
 acquiring a supply temperature of the coolant supplied to the liquid-cooled heat exchanger; and   controlling a flow rate of the coolant of the liquid-cooled heat exchanger and/or an exhaust heat amount of the cryocooler compressor based on the acquired supply temperature of the coolant.