| 摘要 |
PURPOSE:To supply a fluid with high efficiency by selecting the proper pressure in accordance with the switching states of valves provided to plural branch pipes of a main pipe and controlling the number of revolutions of a pump motor based on the deviation between said proper pressure and the pressure generated actually. CONSTITUTION:A main pipe 4 of fluid is branched into five branch pipes 5, and valves V1-Vn are opened and closed in accordance with a desired quantity of fluid. The flow rate signal detected by a flow rate converter 9 of the pipe 4 is fetched to a pressure operator 12, and the set pressure value corresponding to the desired quantity of fluid is calculated from the flow-rate/pressure characteristics f1-fn obtained previously. Then the characteristics fi is selected 13 and the pressure signal P2 is delivered. The pressure of the pipe 4 is detected 6 to obtain the pressure signal P1. The signal P is obtained from signals P1 and P2 through a prescribed operation 7. Then the number of revolutions of a pump motor is controlled 8 to drive the motor 2. A flow rate controller 10 is controlled by the characteristics fi so that a flow rate control valve 11 is fully opened. Thus the pressure is set in response to the switching state of the valve, and the necessary motive power of a pump is minimized without causing the shortage of fluid. |
