| 摘要 |
PROBLEM TO BE SOLVED: To prevent a liquid storage tank from being deformed by a work gas whose pressure is made high when a superconductive magnet is quenched, prevent the overload operation of a compressor, which results from the feed of a high-pressure work gas into the compressor, and improve the reliability of an extremely low temperature cooling apparatus. SOLUTION: When a superconductive magnet 23 is quenched, a high-pressure on/off valve 25 disposed in a high-pressure pipe 3 interconnecting the outlet port side of a compressor 1 and a liquid helium storage tank 4 having a superconductive magnet 22 disposed therein is put into a closed state. By this method, a work gas whose pressure is made high by the compressor 1 can be prevented from being sent into the liquid helium storage tank 4. Further, when quench is caused, a return side on/off valve disposed in a return pipe 26 interconnecting the suction port side of the compressor 1 and the liquid helium storage tank 4 is put into a closed state. By this method, the overload operation of the compressor, which results from the suction of a high-pressure helium gas into the compressor 1, can be prevented. |
