Check valve is installed to ensure the flow of water inside the pump, so as to ensure the normal operation of the pump. Therefore, as for the installation position of the check valve, whether it is installed in front of the pump or after the pump, it can be divided into two situations:、
One is installed in front of the pump vertical suction end, also known as the bottom valve. The purpose is to do not have to pump water to fill a water pump, because the pump and the pump before the suction pipe when there is no water pump can only idle pumping water, so the pump must be full of water to extract water. The installation of the pump is higher than the liquid level of a method, also known as the negative pressure method.
The other is mounted behind the pump. This installation method is the liquid level is higher than the pump, convenient to start and stop the pump without closing the pump water valve, especially for the mother control pump system, to prevent backflow.
The first outlet of the pump is a soft connection (shock absorber), followed by a check valve, followed by a globe valve (such as a butterfly valve, gate valve, globe valve, etc.).
1、Install check valve first and then gate valve or butterfly valve
Advantage: can protect check valve, especially in parallel pump, when one pump is not started, its outlet door is closed, when the other pump is started, the impact is borne by gate valve or butterfly valve. After check valve failure, the inlet and outlet valve isolation system can be closed for repair.
Disadvantages: gate valve or butterfly valve who will protect? There was a case where the disc of the butterfly valve was broken.
2. Install gate valve or butterfly valve before check valve.
Advantages: the butterfly valve or gate valve can be protected, and the impact force is borne by the check valve.
Disadvantages: who to protect the check valve, the check valve is switched on and off by the pressure difference. If the main pressure is high, the pump pressure is high and the pump pressure is open. If the flow rate is unstable, then the check valve will switch repeatedly. It will affect the service life of the check valve. And the check valve is broken, especially the main control system, which needs to be closed before it can be repaired.
In general, as a result of the check valve opening and closing action is more frequently, internal connection parts and sealed parts are prone to damage, for ease of repair, prevent due to check the situation of the fault and shut down the whole system, from this point of view, the check valve will be packed in export before the gate valve or butterfly valve, is basically all you see is this?