| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum control system for a reduced pressure tank miniaturizing a pressure reducing pump unit, and reducing the manufacturing cost and running cost. SOLUTION: This vacuum control system for the reduced pressure tank alternately performs a pressure reducing operation by the pressure reducing pump unit and a pressure reduction releasing operation by the reduced pressure tank side. The pressure reducing pump unit comprises a booster pump driven first motor having an inverter part, a rear-stage vacuum pump connected to a discharge port side of the booster pump and driven at a prescribed rotation speed by a second motor, and a control panel connected to the first motor and the second motor. The booster pump connected to the pressure reducing tank is so provided as to drive along with the rear-stage vacuum pump at all times and the driving frequency of the first motor is automatically adjusted by the driving control of the inverter part so as to reduce the rotation speed of the booster pump in pressure reducing operation and reducing the rotation speed of the booster pump in pressure reduction releasing operation. |
