Reduced volume gas spring or surge tank for cryocooler

Abstract

A fibrous packing material ( 210 ) is distributed throughout the interior space of a surge tank ( 118 ). The packing material ( 210 ) makes the compression and expansion of gas within the surge tank ( 118 ) relatively more isothermal as compared to an empty tank. Thus, a smaller volume tank can be used without sacrificing performance. As a result, the size and weight requirements of the surge tank ( 118 ) have been reduced.

1 . A cryocooler comprising a surge tank, wherein the tank encloses a space, and fibrous packing material is distributed within the space enclosed by the tank. 
     
     
         2 . The cryocooler of  claim 1  wherein the packing material is glass or metal wool. 
     
     
         3 . The cryocooler of  claim 1  wherein approximately 5 to 10 percent of the volume of the space enclosed by the tank is occupied by the packing material. 
     
     
         4 . The cryocooler of  claim 1  further comprising:
 a regenerator;   a pulsetube, which is coupled to the regenerator; and   an inertance tube, which is located between the pulsetube and the surge tank.   
     
     
         5 . The cryocooler of  claim 4  wherein the packing material is glass wool. 
     
     
         6 . The cryocooler of  claim 4  wherein the packing material is metal wool. 
     
     
         7 . The cryocooler of  claim 4  wherein approximately 5 to 10 percent of the volume of the space enclosed by the tank is occupied by the packing material. 
     
     
         8 . The cryocooler of  claim 1 , wherein the cryocooler is part of an aircraft, a satellite or a spacecraft. 
     
     
         9 . The cryocooler of  claim 1  wherein the packing material is distributed entirely throughout the space enclosed by the tank. 
     
     
         10 . A cryocooler comprising a surge tank, wherein fibrous packing material is distributed substantially throughout a space enclosed by the surge tank to make compression and expansion of gas within the surge tank relatively more isothermal as compared to the surge tank when empty. 
     
     
         11 . The cryocooler of  claim 10  wherein the packing material is glass wool. 
     
     
         12 . The cryocooler of  claim 10  wherein the packing material is metal wool. 
     
     
         13 . The cryocooler of  claim 10  wherein approximately 5 to 10 percent of the volume of the space enclosed by the tank is occupied by the packing material. 
     
     
         14 . The cryocooler of  claim 10 , wherein the cryocooler is part of an aircraft, a satellite or a spacecraft. 
     
     
         15 . The cryocooler of  claim 10  wherein the packing material is distributed entirely throughout the space enclosed by the tank.