| 摘要 |
PURPOSE:To enable a pump to be operated as in its rating and a device to be formed in a small size, by providing a subpositive pressure tank, having a smaller capacity than a positive pressure tank, in a branch line in a side of the positive pressure tank while a subnegative pressure tank, having a smaller capacity than a negative pressure tank, in a branch line in a side of the negative pressure tank. CONSTITUTION:A subpositive pressure tank 11 of capacity smaller than that of a positive pressure tank 3a is provided in a branch line 10 branching from a position between a pressure reducing valve 6 in an inlet side of the positive pressure tank 3a and a compressor 1 and connecting the compressor 1 to a driving pressure outlet 7, while a subnegative pressure tank 13 of capacity smaller than that of a negative pressure tank 4a is provided in a branch line 12 branching from a position between a pressure reducing valve 6 in an inlet side of the negative pressure tank 4a and a vacuum pump 2 and connecting the vacuum pump 2 to the driving pressure outlet 7. Then solenoid valves 14-17 are synchronously operated with a solenoid selector valve 5 by a control device not shown in the drawing. In this way, even if a pressure, for instance, in the positive pressure tank 3a is decreased, compensating the pressure to be ensured by pressurized gas from the subpositive pressure tank 11, any influence of the pressure drop never appears in the driving pressure outlet 7 and a pump 8. Accordingly, the pump can be operated as specified in its rating. |
