| 摘要 |
PURPOSE:To promptly recover negative pressure of an actuator, by connecting a negative pressure source to a negative pressure tank when negative pressure in the negative pressure actuator is at least a prescribed value and connecting the negative pressure source to the negative pressure actuator when said negative pressure in the actuator is below the prescribed value. CONSTITUTION:A negative pressure generating source 12 is connected to a negative pressure storage tank 14 through a negative pressure passage 13 having an opening and closing valve 19, and said tank 14 is connected to a negative pressure actuator 16 through negative pressure passages 15, 21. While the source 12 is directly connected to the actuator 16 through negative pressure passages 18, 21 by bypassing the tank 14. A negative pressure sensor 17 is provided to the actuator 16 and connected to the valve 19 through a wire 24. Then the valve 19 is controlled by the sensor 17 in such a manner that the valve is opened when the actuator 16 is in at least a prescribed negative pressure while closed when the actuator is in pressure lower than prescribed negative pressure. Further the valve 19 is closed by a sensor 25 when the tank 14 is in maximum negative pressure. |
