| 摘要 |
PROBLEM TO BE SOLVED: To prevent surging of a compressor without blowing off pressurized air in the atmosphere, and without adjusting a rotating speed of the compressor. SOLUTION: This helium liquefying refrigeration unit has a flowmeter 7 for detecting a flow rate of helium gas supplied to the compressor 4, a control device 8 for outputting a control signal when detecting a stopping signal of the compressor 4 or when a detecting value of the flowmeter 7 becomes less than a preset value, a heating system 9 arranged in a heat exchange storage tank 3, and a heating control device 10 for controlling the heating system 9 on the basis of the control signal from the control device 8. The control device 8 operates the heating system 9 via the heating control device 10 when detecting the stopping signal of the compressor 4 or when a value of the flowmeter 7 becomes a preset value or less; forcibly vaporizes liquid helium in the heat exchange storage tank 3; and replenishes the helium gas in the compressor 4. Afterwards, when a motor rotating speed of the compressor 4 becomes a preset value or less, the control device 8 stops the heating system 9 via the heating control device 10. COPYRIGHT: (C)2005,JPO&NCIPI
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