Cryogenic refrigerator including separating device

Abstract

A cryogenic refrigerator has a separating device provided between a lower temperature portion and a heat exchanger to selectively separate the lower temperature portion and the heat exchanger, and thus to selectively block heat transfer between the lower temperature portion and the heat exchanger. According to the cryogenic refrigerator, it can have an ability to perform a maintenance operation of the cryogenic refrigerator at normal temperature by blocking heat transfer from the lower temperature portion to the heat exchanger during maintenance after disassembly.

1 . A cryogenic refrigerator comprising: 
 a lower temperature portion;    a heat exchanger; and    a separating device provided between the lower temperature portion and the heat exchanger to selectively separate the lower temperature portion and the heat exchanger, and thus to selectively block heat transfer between the lower temperature portion and the heat exchanger.    
     
     
         2 . The cryogenic refrigerator as claimed in  claim 1 , wherein the separating device includes 
 an upper plate;    a lower plate having a shape corresponding to that of the upper plate; side plates connecting the upper plate and the lower plate to form a cavity portion therein; and    a conduit supplying gas into or discharging gas from the cavity portion,    wherein, when the gas is supplied into the cavity portion, the separating device is expanded to separate the upper plate and the lower plate away from each other, and thus to block the heat transfer between the lower temperature portion and the heat exchanger, and when the gas is discharged from the cavity portion, the separating device is contracted to closely contact the upper plate with the lower plate toward each other, and thus to permit the heat transfer between the lower temperature portion and the heat exchanger.    
     
     
         3 . The cryogenic refrigerator as claimed in  claim 2 , wherein the separating device is made from aluminum, copper, stainless steel, or oxygen-free copper.  
     
     
         4 . The cryogenic refrigerator as claimed in  claim 2 , wherein the gas supplied into the cavity portion consists of nitrogen, helium, or argon.  
     
     
         5 . The cryogenic refrigerator as claimed in  claim 2 , wherein an adhesive layer is applied onto opposite faces of the upper plate and the lower plate of the separating device.  
     
     
         6 . The cryogenic refrigerator as claimed in  claim 5 , wherein the adhesive layer consists of indium.  
     
     
         7 . The cryogenic refrigerator as claimed in  claim 2 , wherein the separating device includes two or more conduits adapted for supplying the gas into or discharging the gas from the cavity portion.