Patent ID: 6393847
Filing Date: 2002-05-28
Classification: F17C,F25D

Abstract:
In a vacuum insulated dewar having an inner tank with a bottom reservoir containing a pool of cryogenic liquid, a top opening for inserting and removing specimens, and a tray for storing specimens thereon in vertically disposed racks said tray being disposed above the pool of cryogenic liquid, the improvement comprising:a vertically disposed, cylindrical thermally conductive element connected to the tray, a portion of said cylindrical element extending upwardly to a position near a top of the dewar, said cylindrical element having a portion extending below the tray so as to be, at least partially, immersed in said pool of cryogenic liquid; wherein said cylindrical element surrounds the tray and the specimens stored thereon, whereby said cylindrical element absorbs heat in the dewar and transfers it to the pool of cryogenic liquid, thereby to enhance evaporation so that resulting vapor may rise to limit undesirable temperature rise in the racks located near the top of said dewar.