Oil lubrication-type compressor for cryocooler

Abstract

An oil lubrication-type compressor for a cryocooler includes an air-cooled heat exchanger that includes a cooling fan and a first oil line disposed to be forcibly cooled by the cooling fan and a second oil line that bypasses the first oil line.

What is claimed is: 
     
         1 . An oil lubrication-type compressor for a cryocooler comprising:
 an air-cooled heat exchanger that includes a cooling fan and a first oil line disposed to be forcibly cooled by the cooling fan; and   a second oil line that bypasses the first oil line.   
     
     
         2 . The oil lubrication-type compressor for a cryocooler according to  claim 1 ,
 wherein the second oil line is disposed to be forcibly cooled by the cooling fan.   
     
     
         3 . The oil lubrication-type compressor for a cryocooler according to  claim 2 ,
 wherein the air-cooled heat exchanger includes an orifice provided at at least one of the first oil line and the second oil line so that a difference between a flow rate of an oil of the first oil line and a flow rate of an oil of the second oil line is reduced.   
     
     
         4 . The oil lubrication-type compressor for a cryocooler according to  claim 1 ,
 wherein the second oil line bypasses the air-cooled heat exchanger.   
     
     
         5 . The oil lubrication-type compressor for a cryocooler according to  claim 4 ,
 wherein the second oil line includes an on-off valve that operates to be closed when the cooling fan is operated and to be opened when the cooling fan is stopped.   
     
     
         6 . The oil lubrication-type compressor for a cryocooler according to  claim 1 ,
 wherein the air-cooled heat exchanger cools a refrigerant gas line.   
     
     
         7 . The oil lubrication-type compressor for a cryocooler according to  claim 1 , further comprising:
 a liquid-cooled heat exchanger that is connected in series upstream of the air-cooled heat exchanger.   
     
     
         8 . The oil lubrication-type compressor for a cryocooler according to  claim 7 , further comprising:
 an oil temperature sensor that is provided upstream or downstream of the liquid-cooled heat exchanger or that is provided downstream of the air-cooled heat exchanger,   wherein the cooling fan operates based on an oil temperature measured by the oil temperature sensor.   
     
     
         9 . The oil lubrication-type compressor for a cryocooler according to  claim 7 ,
 wherein the liquid-cooled heat exchanger further includes a refrigerant gas temperature sensor that is provided upstream or downstream of the liquid-cooled heat exchanger on a refrigerant gas line, and   the cooling fan operates based on a refrigerant gas temperature measured by the refrigerant gas temperature sensor.