| 摘要 |
PURPOSE:To surely supply air from an air tank into a pressurized oil tank in a hydraulic power plant or the like, by providing an unloader valve with a valve action detecting switch which functions in connection with the action of the unloader valve during the stoppage of operation of a main machine to start or stop a pressurized oil pump. CONSTITUTION:When a main machine is out of operation, a motor drive circuit for a pressurized oil pump 6 is chagned over by a pressure switch 2. When the oil pressure in a pressurized oil tank 1 is high, the pressurized oil pump 6 is not moving. When the oil pressure in the tank 1 is low, an unloader valve 4 is shifted from the unloading condition to the loading condition and the pressure switch 2 is turned on by a pressure change applied from a pilot valve 3, to start the pressurized oil pump 6. Since air and oil are put in when the unloader valve 4 is in the unloading condition, the air is surely supplied from an air tank 7 into the pressurized oil tank 1 when the unloader valve is in the loading condition. |
