| 摘要 |
PURPOSE:To cool a lead wire sufficiently by liquefying a refrigerant gas stored in a buffer tank by the excess refrigerating capacity of a refrigerator on the non-use of the lead wire while returning the gas into a heat-insulating vessel. CONSTITUTION:Helium gas which has been stored in a buffer tank 17 is compressed by a compressor 7, liquefied by the excess capacity of a refrigerator 6 and returned into an inner vessel 1 at a point of time when currents are adjusted completely. When lead wires 19a, 19b are employed, helium gas used for cooling the lead wires 19a, 19b is stored previously into the buffer tank 17. When the lead wires 19a, 19b are not employed, helium gas stored in the buffer tank 17 is liquefied by the excess capacity of the refrigerator 6 and returned into the inner vessel 1. Accordingly, the lead wires can be cooled excellently when the lead wires 19a, 19b are used, and the reduction of helium gas can be prevented, thus obtaining a superior cooling effect. |
