| 摘要 |
PURPOSE:To increase the achievable degree of vacuum, in a vacuum apparatus comprising a high vacuum pump and an auxiliary pump, i.e. a vacuum pump for rotating the oil, by controlling the rotation of the oil rotating pump by means of an inverter. CONSTITUTION:A high vacuum pump, i.e. an oil diffusion pump DP is provided with an auxiliary pump, e.g. a vacuum pump RP for rotating the oil and an inverter INV for controlling the rotation thereof. When the rotation of the oil rotating pump RP is increased in order to discharge the air from a vacuum chamber VC, the oil temperature thereof increases and the achievable degree of vacuum drops, thereby the rotation of the oil rotating pump RP is dropped by means of an inverter INV. When argon gas is led into the vacuum chamber, the gas must be discharged continuously, thereby the rotation of the oil rotating pump is increased by means of the inverter INV. Consequently, the achievable degree of vacuum can be increased and the operational noise of the oil rotating pump can be reduced.
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