Which position is more suitable for the check valve to be installed?

Which position is more suitable for the check valve to be installed?

Check valve is an automatic valve. It depends on the pressure of the flowing medium in the pipeline to push the disc to close and open the valve. When the medium stops flowing, the disc of the check valve closes, which can effectively prevent the medium in the pipeline from occurring. To ensure the safety of the pipeline, backflow plays a big role on it.

The idea of installing the check valve is to ensure the flow direction of the water flow inside the pump, so as to ensure the normal operation of the pump. Therefore, regarding the installation position of the check valve, whether it is installed in front of the water pump or after the water pump can be divided into two positions:

First is installed at the end of the vertical suction pipe in front of the water pump, also called a bottom valve. The purpose is to fill the water pump once without pumping water once, because the water pump can only idle when there is no water in the water pump and the suction pipe in front of the pump, so the water pump must be filled with water to pump out water. The installation of this water pump is a method above the liquid level, also called negative pressure method.

The check valve must be installed at the outlet of the pump, before the outlet control valve, so that the check valve can be repaired. Generally, the first outlet of the pump is a soft connection (shock absorber), followed by a check valve, and then a block valve (such as butterfly valve, gate valve, globe valve, etc.)

1. Install the check valve first and then install the gate valve or butterfly valve

Advantages: It can protect the check valve, especially in parallel pumps. When one pump is not started, its outlet door is closed, and when the other pump is started, the impact force is borne by the gate valve or butterfly valve. After the check valve fails, the inlet and outlet valve isolation system can be closed for repair.

Disadvantages: who will protect the gate valve or butterfly valve? There was a case where the valve plate of the butterfly valve was broken.

2. Install the gate valve or butterfly valve first and then the check valve

Advantages: It can protect the butterfly valve or gate valve, and the impact force is borne by the check valve.

Disadvantages: Who will protect the check valve? The check valve is switched on and off by pressure difference. If the pressure of the main pipe is high, it will be closed, and the pressure of the pump will be opened. If the flow rate used is unstable, the check valve will open and close repeatedly. Affect the life of the check valve. Moreover, the check valve is broken, especially the main control system, which can only be repaired after the system is shut down.