| 摘要 |
PURPOSE:To improve the workability of the titled device when it is installed, by providing a flow rate arithmetic device which supplies the electric signals in response to the differential voltage electric signal between the primary and secondary sides of a pressure reducing valve as well as the opening of said valve and then calculates the signals corresponding to the water supply quantity. CONSTITUTION:A pressure reducing valve 2 is connected between a water supply pipe 1 connected to a water supply source and a water supply pipe 1' connected to a demand terminal. Then the primary pressure signal SP1 and the secondary pressure signal SP2 of outputs of pressure detectors 3 and 3' and the valve opening signal S12 of output of a valve opening detector 2c are supplied to a flow rate arithmetic circuit 4. The circuit 4 obtains the differential pressure between signals SR1 and SR2 through a subtractor 4a and supplies it to an operator 4b to be calculated with the signal SZ. Then the flow rate signal SQ is supplied to a pressure control circuit 5. The circuit 5 decides the pressure set value through a function generator 5a, and a comparator 5b compares the set value with the feedback value SP2 and supplies the control output to an operating device 5c so as to obtain coincidence between both values. Thus the drive signal SD is supplied to the valve 2. In such a way, it is possible to ensure the pressure reducing control without providing a flow rate detector to the water supply pipe. This improves greatly the workability of a water supply pressure reducing valve device when it is installed. |
