Install a check valve to ensure the direction of water flow in the pump to ensure proper pump operation. Therefore, regarding the installation position of the check valve, it can be divided into two cases whether it is installed before or after the pump: one is the end of the vertical suction pipe installed in the front of the pump, also known as the bottom valve. The purpose is to fill the pump once without pumping. Because there is no water in the pump and in the suction pipe in front of the pump, the pump can only pump in when it is idling, so the pump must be filled with water to pump water. This The water pump installation is a method when the liquid level is high, also known as the negative pressure method. The other is installed behind the pump. This installation method is performed with the liquid level above the pump, which makes it easy to start and stop the pump without closing the pump outlet valve, especially for mother-controlled pump systems, to prevent backflow. The check valve must be installed at the pump outlet and before the outlet control valve in order to service the check valve. The first outlet of a normal pump is a soft connection (shock absorber), then a check valve, then a globe valve (eg butterfly valve, gate valve, globe valve, etc.).
