| 摘要 |
PURPOSE:To prevent an excessive or lowered level of the flow rate discharged from pumps although some large-diameter pumps are included, by stopping the sequence with a flow rate deviation corresponding to each pump despite diferent capacities of pups in pump groups. CONSTITUTION:First, the output DELTAP=P0-F0(P: simlated discharge flow rate signal, F0: flow rate setting signal) of a comparator 12 is checked. An alarm setting device 13-L delivers a signal DL when DELTAP>=DELTAPL(PL: flow rate dischrged from a large-diameter pump) is satisfied, and a pin board setting device 15 is lowered by a step via a stepping relay 14. Output signals 20-1-20-n of the device 15 deliver stop signals of the following stages via a stop command delay circuit 16 to stop the operation of a pump. When DELTAPS<=DELTAP<=DELTAPL(DELTAPS: flow rate discharged from a small-diameter pump) is satisfied, the deivce 15 is reset by a step. Then the DELTAP is checked at that moment. The operation of a small- diameter pump is stopped in the case of DELTAP>=0: while the number of working pumps is maintained in the case of DELTAP<0 respectively. |
