| 摘要 |
PURPOSE:To provide the high degree of vacuum in a short time, by a method wherein an amount of water fed in a vacuum pump is decreased when the degree of vacuum on the suction side is decreased, and is increased when increased. CONSTITUTION:When the degree of vacuum at a suction port part is still low right after the starting of operation, an electromagnetic valve 12 is closed, and a small amount water, only passing a throttle flow passage 16, is fed in a casing 3. When the degree of vacuum on the suction side is increased during elapse of a time after the starting of operation, an electromagnetic valve 12 is opened by means of a signal from a pressure switch 13. In which case, quantities of water passing two throttle flow passages 15 and 16 is supplied in a vacuum pump. This constitution enables provision of the high degree of vacuum in a short time.
|
