Superconducting magnet system with refrigerator for re-liquifying cryogenic fluid in a tubular conduit

Abstract

A superconducting magnet system with a superconducting magnet coil system, which is disposed in a cryogenic fluid tank ( 2 ) of a cryostat ( 1 ), and an exchangeable refrigerator ( 5; 31 ) which is operated in a vacuum container ( 8 ) and is provided to re-liquify the cryogenic fluid flowing through a tubular conduit ( 4; 21 ) is characterized in that the tubular conduit ( 4; 21 ) is rigidly installed in the cryostat ( 1 ). The refrigerator reaches its optimum performance during operation in a vacuum, and can be easily exchanged in case of a defect.

1 . A superconducting magnet system comprising: 
 a cryostat;    a cryogenic fluid tank disposed in said cryostat;    a superconducting magnet coil system disposed in said cryogenic fluid tank;    a vacuum container defined by said cryostat;    an exchangeable refrigerator disposed in said vacuum container;    a tubular conduit through which cryogenic fluid flows, said tubular conduit in thermal communication with said refrigerator to liquify said cryogenic fluid, said tubular conduit being rigidly installed in said cryostat.    
   
   
       2 . The superconducting magnet system of  claim 1 , wherein said refrigerator has a first metallic coupling device, which permits heat transfer from said tubular conduit to a cooling region of said refrigerator.  
   
   
       3 . The superconducting magnet system of  claim 2 , wherein said first metallic coupling device has concentric disc-like elements.  
   
   
       4 . The superconducting magnet system of  claim 3 , wherein a section of said disc-like elements has a shape of part of a slotted ring.  
   
   
       5 . The superconducting magnet system of  claim 2 , wherein said tubular conduit has a second coupling device which permits heat transfer from said tubular conduit to a cooling region of said refrigerator.  
   
   
       6 . The superconducting magnet system of  claim 5 , wherein said second metallic coupling device has concentric annular elements.  
   
   
       7 . The superconducting magnet system of  claim 5 , wherein said first and/or said second metallic coupling device is made from copper or aluminium.  
   
   
       8 . The superconducting magnet system of  claim 1 , wherein said tubular conduit is substantially helical.  
   
   
       9 . The superconducting magnet system of  claim 1 , wherein said tubular conduit has several parallel, interconnected annular sections.  
   
   
       10 . The superconducting magnet system of  claim 1 , wherein said tubular conduit has an inner diameter of between 2 mm and 8 mm.  
   
   
       11 . The superconducting magnet system of  claim 1 , wherein said tubular conduit is made from stainless steel.  
   
   
       12 . The superconducting magnet system of  claim 1 , wherein said refrigerator is substantially rotationally symmetrical in a region facing said tubular conduit.  
   
   
       13 . The superconducting magnet system of  claim 1 , further comprising a guidance for installation and removal of said refrigerator.  
   
   
       14 . The superconducting magnet system of  claim 13 , wherein said guidance comprises at least one rail.  
   
   
       15 . The superconducting magnet system of  claim 13 , wherein a region of said refrigerator facing said tubular conduit is substantially conical and a region of said tubular conduit facing said refrigerator is substantially funnel-shaped.  
   
   
       16 . The superconducting magnet system of  claim 5 , wherein a region of said refrigerator facing said tubular conduit is substantially conical and a region of said tubular conduit facing said refrigerator is substantially funnel-shaped.  
   
   
       17 . The superconducting magnet system of  claim 16 , wherein said region of said refrigerator facing said first metallic coupling device is substantially conical and said region of said tubular conduit facing said second metallic coupling device is substantially funnel-shaped.  
   
   
       18 . The superconducting magnet system of  claim 1 , wherein said vacuum container is made from magnetic material.  
   
   
       19 . The superconducting magnet system of  claim 1 , wherein the cryogenic fluid is helium.  
   
   
       20 . The superconducting magnet system of  claim 1 , wherein the cryogenic fluid is hydrogen, neon, or nitrogen.  
   
   
       21 . The superconducting magnet system of  claim 1 , wherein said refrigerator comprises a pulse tube cooler.  
   
   
       22 . The superconducting magnet system of  claim 1 , wherein the refrigerator comprises a Gifford-McMahon cooler.  
   
   
       23 . The superconducting magnet system of  claim 1 , wherein magnet system is structured for a magnetic resonance apparatus.