Where should the check valve be installed?

Today we will discuss the check valve installation position. So how is the installation position of the check valve determined? What is the difference between the pre-pump installation and the post-pump installation check valve, and where is the pump front installation suitable for? Check valves are usually used with other valves. When used with other valves, where is the check valve installed? Let’s discuss it together.

check valve
The check valve, also called the check valve, is an automatic valve that relies on the pressure of the flowing medium in the pipe to push the valve flap to close and open the valve. When the medium stops flowing, the check valve flap closes, which can be effective. Preventing the backflow of the medium in the pipeline plays a big role in ensuring the safety of the pipeline.


The check valve is divided into structures according to the structure, and can be divided into three types: a lift check valve, a swing check valve and a butterfly check valve. Lift check valves are available in both vertical and straight versions. The swing check valve is divided into three types: single-lobed, double-lobed, and multi-lobed. The butterfly check valve is divided into a butterfly double flap and a butterfly single flap. The above several check valves can be divided into four types: a screw connection, a flange connection, a welding and a clip type connection.

The check valve is installed to ensure the flow of water inside the pump, thus ensuring the normal operation of the pump. Therefore, regarding 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 at the end of the vertical suction pipe of the pump, also called the bottom valve. The purpose is to charge the water pump once without pumping water, because the pump can only be idling and not pumping water when there is no water in the suction pipe in the pump and before the pump, so the pump must be filled with water to extract water. This type of pump is installed above the liquid level, also known as the negative pressure method.


The other is installed behind the pump. This kind of installation method is that when the liquid level is higher than the water pump, it is convenient to start and stop the water pump without shutting off the water pump outlet valve, especially for the mother control water pump system to prevent backflow.


The check valve must be installed in front of the pump outlet and outlet control valve to access the check valve. The first exit of the general pump is a soft connection (shock absorber), followed by a check valve, followed by a shut-off valve (such as butterfly valve, gate valve, globe valve, etc.)


1. Install the gate valve or butterfly valve after installing the check valve first.

Advantages: The check valve can be protected, especially in parallel pumps. When one pump does not start, its outlet door is closed, and when another pump is started, the impact force is the responsibility of the gate valve or the butterfly valve. After the check valve fails, the inlet and outlet valve isolation system can be closed for repair.

Disadvantages: Who is the gate valve or butterfly valve to protect? There has been a case where the valve plate of the butterfly valve was smashed.


2, first install the gate valve or butterfly valve after the check valve

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

Disadvantages: Whoever protects the check valve, the check valve is switched by the pressure difference. If the pressure of the main pipe is high, the pressure of the pump is high. If the flow rate is unstable, the check valve will be repeatedly switched. Affect the life of the check valve. Moreover, the check valve is broken, especially the parent control system, which needs to be shut down before repairs can be made.

In general, due to the frequent opening and closing action of the check valve, the internal connecting portion and the sealing member are easily damaged, and in order to facilitate the repair and prevent the shutdown of the entire system due to the failure of the check valve, from this point of view, the check is considered. The valve will be installed before the exit gate valve or butterfly valve. Is it basically the same?

Post time: Dec-21-2018

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