| 摘要 |
PURPOSE:To obtain a highly reliable control system capable to leading the pump operation to the safe side by adding a simple monitoring means and an interlock circuit to the flow regulating circuit. CONSTITUTION:A pump flow rate monitor 36, an opening monitor consisting of limit switches 40 and 41 which detect the opening position of a recirculation flow regurating valve 39, and an interlock circuit 42 which opens and closes the regulating valve 39 according to the specified determination made based on the outputs of said monitors are provided on a pump recirculation flow control circuit. When the detectors detect that the flow reached the upper limit of the flow rate set by the monitor 36 and yet the regulating valve 39 has not been fully closed by the fully closing limit switch 40, the interlock 42 actuates a solenoid valve 38 to drive the regulating valve 39 to the fully closed position, and when the detectors detect that the flow reached the lower limit of the flow rate set by the monitor 36 and yet the valve was fully closed by the limit switch 41, the interlock circuit actuates the solenoid valve 38 to drive the regulating valve to the fully opened position. |
