Refrigerator

Abstract

A pulse tube refrigerator has a pulse tube having a first end and a second end. A inertance tube connects the first end and a buffer tank. A pressure change generator is connected with the second end. The pressure change generator generates a pressure change of a working gas at the second end periodically. A first flow straightener provided at the first end. A second flow straightener provided at the second end. A degree to which the first flow straightener hinders the flow of the working gas is greater than a degree to which the second flow straightener hinders the flow of the working gas.

What is claimed is: 
     
         1 . A pulse tube refrigerator, comprising:
 a pulse tube having a first end and a second end;   a inertance tube connecting the first end and a buffer tank;   a pressure change generator connected with the second end, configured to generating a pressure change of a working gas at the second end periodically;   a first flow straightener provided at the first end;   a second flow straightener provided at the second end; and   wherein a degree to which the first flow straightener hinders the flow of the working gas is greater than a degree to which the second flow straightener hinders the flow of the working gas.   
     
     
         2 . The pulse tube refrigerator according to  claim 1 , wherein a frequency of the pressure change is 30 Hz or higher. 
     
     
         3 . The pulse tube refrigerator according to  claim 1 ,
 wherein a value obtained by dividing the degree to which the first flow straightener hinders the flow of the working gas by the degree to which the second flow straightener hinders the flow of the working gas is within a range of 4 to 8.   
     
     
         4 . The pulse tube refrigerator according to  claim 1 ,
 wherein, the second flow straightener has a stacked structure in which N metal screens having the substantially same mesh are stacked, and the first flow straightener has a stacked structure in which M metal screens having the substantially same mesh as the mesh of the metal screens are stacked, wherein M is a natural number and N is a natural number greater than N.