Cryorefrigeration Device and Method of Implementation

Abstract

The invention proposes a reliable high-performance cryorefrigeration device, the level of thermal oscillations of which may be minimized so as to be below a threshold value. For this purpose, the subject of the invention is a cryorefrigeration device comprising N periodically operating cryorefrigerators ( 100 ), N being an integer equal to or greater than 2, each cryorefrigerator being provided with a cold end coupled to a common cold end ( 300 ), the cryorefrigerators being linked to a control device provided with a phase-shift means capable of making the cryorefrigerators operate in phase-shifted relationship one with respect to another.

1 . A cryorefrigeration device comprising N periodically operating cryorefrigerators, where N is an integer equal to or greater than 2, each provided with a cold end connected to a common cold end, the cryorefrigerators being associated with a control device provided with a phase-shift means suitable for actuating phase-shifted operation of the cryorefrigerators with regard to one another, characterized in that the cold end of each cryorefrigerator is connected to the common cold end via a heat conducting mechanical uncoupling means. 
     
     
         2 . The device as claimed in  claim 1 , in which the phase-shift means is suitable for actuating a phase-shifted operation with a phase difference of 2π/N, to within 5 degrees, between each cryorefrigerator. 
     
     
         3 . The device as claimed in  claim 1 , in which the cryorefrigerators are identical. 
     
     
         4 . The device as claimed in  claim 1 , in which the cryorefrigerators are pulse tube refrigerators or Gifford-MacMahon cryorefrigerators. 
     
     
         5 . The device as claimed in  claim 1 , in which the heat conducting mechanical uncoupling means comprises a plurality of heat conducting wire braids fixed between two mounting plates in thermal contact with the cold end of a cryorefrigerator and the common cold end, respectively. 
     
     
         6 . The device as claimed in  claim 5 , in which the heat conducting wires of the braids are made from Cu/a1 copper and have a diameter between 0.03 mm and 0.1 mm, preferably equal to 0.05 mm, and the mounting plates have a residual resistivity ratio of at least 50. 
     
     
         7 . The device as claimed in  claim 5 , in which the mounting plates and/or the common cold end are made from Cu/a1 or Cu/c1 copper. 
     
     
         8 . The device as claimed in  claim 5 , in which the heat conducting wires of the braids are welded to the mounting plates by electron beam welding so as to ensure material continuity. 
     
     
         9 . The device as claimed in  claim 1 , in which the common cold end comprises a temperature sensor connected to the control device. 
     
     
         10 . A method for using a cryorefrigeration device as claimed in  claim 1 , comprising a step of actuating the N cryorefrigerators in a phase-shifted manner with regard to one another, characterized in that it comprises a step of adjusting the phase difference between each of the N cryorefrigerators, this adjustment step comprising the following steps:
 a1) operating the N cryorefrigerators simultaneously, in any phase-shifted manner;   b1) measuring the temperature variations of the common cold end with the temperature sensor and calculating the mean temperature of the common cold end;   c1) actuating a phase-shifted operation between each cryorefrigerator until the temperature variations of the common cold end during the operation of the cryorefrigeration device are lower than a threshold value, preferably less than 2% in absolute value of the mean temperature of the common cold end, advantageously less than 1% in absolute value of the mean temperature of the common cold end;   d1) setting the operating phase of each of the N cryorefrigerators.   
     
     
         11 . The method for using a cryorefrigeration device as claimed in  claim 1 , comprising a step of actuating the N cryorefrigerators in a phase-shifted manner with regard to one another, characterized in that it comprises a step of adjusting the phase difference between each of the N cryorefrigerators, this adjustment step comprising the following steps:
 a2) operating the N cryorefrigerators simultaneously, with a phase difference of 2π/N between each cryorefrigerator;   b2) measuring the temperature variations of the common cold end with the temperature sensor and calculating the mean temperature of the common cold end;   c2) varying the phase of N-1 cryorefrigerators about their initial phase in step a) until the temperature variations of the common cold end during the operation of the cryorefrigeration device are lower than a threshold value, preferably less than 2% in absolute value of the mean temperature of the common cold end, advantageously less than 1% in absolute value of the mean temperature of the common cold end;   d2) setting the operating phase of each of the N cryorefrigerators.