| 摘要 |
<p>PURPOSE:To easily and continuously perform pressure-intensifying and reducing operations for a control circuit by only one pressure control valve as well as permit the reduction of pressure by a pressure intensifier itself by utilizing a change in volume due to combinations of plural pressure intensifiers. CONSTITUTION:Stop valves 17 and 18 are each provided to pipelines 19 and 20 connecting the high-pressure side chambers 9 and 10 of pressure intensifiers 7 and 8 with a pressure oil discharge 6. Also, the high-pressure side chambers 9 and 10 are connected to a low-pressure pump 4 through pipelines 24 and 25 with stop valves 21 and 22 and a direction switch valve 23. And, cylinders 26-29 for opening and closing operations are provided to each of the stop valves 17, 18, 21, and 22, which are controlled by direction switching pilot valve 39-33. On the other hand, the low- pressure side chambers 11 and 12 of the pressure intensifiers 7 and 8 are connected to a high-pressure pump 5 through pipelines 41 and 42 with check valves 37 and 38 and direction switch valves 39 and 40. These direction switch valves 35, 39, 40, and 43 are connected to an oil tank 1 through a return circuit 48 connected with the discharge pipeline of the pump 5 through an electromagnetic proportion-type pressure control valve 49.</p> |
