Gas phase shifting inertance gap pulse tube cryocooler

Abstract

A pulse tube cryocooler including a heat exchanger and a pulse tube is modified with an in-line inertance gap attached to the pulse tube for gas phase shifting of gas pressure in the cryocooler for improving the efficiency and temperature range of pulse tube cryocoolers.

1 . A cryocooler for exchanging heat between a first volume and a second volume, the cryocooler comprising,
 a first stage defining a first volume for containing gas at a first temperature and first pressure,   a second stage defining a second volume for containing the gas at a second temperature and second pressure, and   a controlled gas phase shifting device between the first volume and the second volume, the controlled gas phase shifting device providing a pressure and temperature phase difference between the first volume and the second volume, wherein,   the cryocooler is a pulse tube cryocooler,   the gas phase shifting device is an inertance gap,   the first stage comprises a stationary heat exchanger and an exit volume as the first volume,   the second stage comprises a pulse tube, the gas phase shifting device, and a reservoir volume, and   the reservoir volume is the second volume.   
   
   
       2 . The cryocooler of  claim 1  wherein,
 the cryocooler is selected from a group consisting of coolers, heaters, and heat pumps.   
   
   
       3 . The cryocooler of  claim 1  wherein,
 gas mass flow in the first volume exit is in phase with the gas pressure.   
   
   
       4 . The cryocooler of  claim 1  wherein,
 the cryocooler comprises a compressor, and   the compressor injects gas through the stationary heat exchanger and exit volume and through the pulse tube and through the inertance gap and into the reservoir.   
   
   
       5 . The cryocooler of  claim 1  wherein,
 the inertance gap is a flow inertia device.   
   
   
       6 . The cryocooler of  claim 1  wherein,
 the inertance gap is a flow inertia device, and   the inertance gap is defined by a width, length, and thickness.   
   
   
       7 . The cryocooler of  claim 1  wherein,
 the stationary heat exchanger has a warm end and a cold end,   the second volume being the cold end coupled to the pulse tube.   
   
   
       8 . The cryocooler of  claim 1  wherein,
 the second volume is surge volume.   
   
   
       9 . The cryocooler of  claim 1  wherein,
 the inertance gap is formed by concentric rings.   
   
   
       10 . The cryocooler of  claim 1  wherein,
 the inertance gap is formed by parallel plates.   
   
   
       11 . The cryocooler of  claim 1  wherein,
 cooling of gas from the first volume to the second volume is controlled by gas flow inertia for controlling mass flow and pressure waves between the first volume and the second volume.