Help needed with the switching steps for a reciprocating pump.

It is not clear whether the speed control system of reciprocating pumps includes frequency modulation; in common reciprocating pumps, a bypass valve (return valve) is used for circulation control in order to regulate the flow rate. During the switching operation, after starting the backup pump, the circulation valve is used to regulate the pressure at the pump outlet to match the system pressure; meanwhile, the return valve keeps the pressure from dropping, and the circulation valve of the offline reciprocating pump is gradually opened fully. Because of the function of the check valve installed at the pump outlet, it is possible to fully close the outlet valve of the pump in question. It is worth noting here that once a check valve leaks, it is necessary to use the outlet valve and backflow valve to maintain pressure and shut down the pump. For reference. There should be relevant job operation procedures for such operations.

Generally, before starting the backup pump, the exhaust valve should be opened to prevent the pump from being overpressured. Once it is operating properly, the suction valve can be gradually opened. After everything is working normally, the suction valve of the running pump should be closed first, and then the exhaust valve should be opened after the pump is stopped (a check valve is required for this)