Pulse tube refrigerator

Abstract

A pulse tube refrigerator ( 1 ) comprises one or more stages ( 7, 10 ). Each stage comprises a pulse tube ( 5, 8 ) and a regenerative heat exchanger ( 6, 9 ), the heat exchanger comprising a foam matrix material ( 16 ).

1 . A pulse tube refrigerator comprising one or more stages, wherein each stage comprises a pulse tube and a regenerative heat exchanger, the heat exchanger comprising a foam matrix material.  
     
     
         2 . A pulse tube refrigerator according to  claim 1 , wherein the foam comprises metal or ceramics.  
     
     
         3 . A pulse tube refrigerator according to  claim 1 , wherein the foam comprises one of copper, copper bronze, stainless steel, lead, erbium nickel or holmium copper foam.  
     
     
         4 . A pulse tube refrigerator according to  claim 1 , the foam comprising a metal foam including ceramic compounds, wherein the ceramic compounds include Al 2 O 3  , GdAlO 3 , AIN-type ceramics, or further Gadolinium based compounds.  
     
     
         5 . A pulse tube refrigerator according to  claim 1 , wherein the foam has a porosity in the range 75% to 95%.  
     
     
         6 . A pulse tube refrigerator according to  claim 1 , further comprising at least one of warm end and cold end recuperative heat exchangers, wherein the recuperative heat exchangers comprise a foam matrix material.  
     
     
         7 . A pulse tube refrigerator according to  claim 1 , wherein the regenerative heat exchanger operates in a temperature range of 2K to 10K.