| 摘要 |
PURPOSE: To eliminate a restriction of a fixing position of a multi-stage type freezer and further to enable refrigerant gasified in a cryogenic tank to be efficiently cooled and liquified by a method wherein the cryogenic refrigerant gas evaporated within the cryogenic refrigerant tank is fed to a heating stage in the multi-stage type freezer and returned back again to the cryogenic refrigerant tank. CONSTITUTION: Helium gas evaporated within a helium tank 2 is fed to a heat exchanger 22 fixed to a third stage heating stage 12 by a refrigerant supplying pipe 23 and a blower 21, liquified again there and returned back to the helium tank 2 through the refrigerant supplying pipe 24, resulting in that a fixing location of the three-stage type freezer 20 can be freely selected with arrangement and configuration of the refrigerant supplying pipes 23, 24 and the fixing location of the three-stage freezer 20 may not be placed at another location where it is not thermally connected to a position having upper gaseous phase in the helium tank 2. Accordingly, since the fixing position of the three-stage type freezer 20 is placed at a waist height of a worker, a maintenance work such as a removing or a fixing of the internal component parts may be facilitated. |
