| 摘要 |
PROBLEM TO BE SOLVED: To stably operate a multistage vacuum pump over a long period of time by introducing purging inert gas in a pump according to a flow rate of process gas flowing in the pump without causing an adverse influence on the exhaust performance of the pump, and without increasing running cost. SOLUTION: This multistage vacuum pump includes a pressure sensor 42 detecting pressure on the intake side of the downstream side final stage 34, an inert gas introducing pipe 44 introducing purging inert gas to the intake side of the downstream side final stage 34, a valve element 46 arranged in the inert gas introducing pipe 44, and a control part 48 for controlling the opening/closing of the valve element 46 according to a pressure value detected by the pressure sensor 42. COPYRIGHT: (C)2009,JPO&INPIT
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