Patent ID: 6144274
Filing Date: 2000-11-07
Classification: F25D,H01F

Abstract:
In a superconducting magnet including an vacuum vessel and a selectively insertable and removable cryocooler within a sealed cavity enabling the cryocooler to be inserted and removed without breaking the vacuum or discontinuing superconducting operation of the magnet, a positioning assembly comprising:a guide assembly secured to said superconducting magnet including a guide tube extending parallel to the axis of said cryocooler; andan axially extending slider assembly including a rod secured to said cryocooler for movement therewith and positioned and dimensioned for said rod to fit closely within and slide within said guide as said cryocooler is inserted into said sealed cavity, and to be removed from said superconducting magnet upon removal of said cryocooler from said superconducting magnet;said guide assembly and extending rod maintaining the axis of said cryocooler along the axis of said sealed cavity in the presence of magnetic forces of a magnetic field generated by said superconducting magnet and acting on said cryocooler;wherein said guide is a tube including an axial opening dimensioned to closely surround said axial extending rod and said axial extending rod is long enough to enable engagement of said rod with said guide tube before said cryocooler is sufficiently positioned within said sealed cavity to be subjected to said magnetic forces;whereby said guide assembly assists in resisting said magnetic forces to facilitate the proper positioning and axial alignment of said cryocooler in said superconducting magnet.