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Today, let’s discuss the installation position of the check valve. How to determine the installation position of the check valve? What is the difference between the check valve installed in front of the pump and the check valve installed behind the pump? Where is the check valve installed in front of the pump applicable? Check valves are usually used together with other valves. Where should check valves be installed when they are used together with other valves? Next, we will introduce the specific methods to you.

The check valve, also known as the non return check valve, is an automatic valve. It relies on the pressure of the flowing medium in the pipeline to push the valve disc to close and open the valve. When the medium stops flowing and the check valve disc closes, it can effectively prevent the backflow of the medium in the pipeline, which plays a great role in ensuring the safety of the pipeline.

1. Check valves are classified by structures

Unlike brass ball valves for water, the check valves can be divided into lift check valve, swing check valve and butterfly check valve. Lift check valves can be divided into vertical and straight through. Swing check valves are divided into single valve, double valve and multi valve. Butterfly check valves are divided into butterfly double valve and butterfly single valve. The above check valves can be divided into threaded connection, flange connection, welding and wafer connection.

2. Two ways to determine the installation position of the non return check valve

The check valve is installed to ensure the flow direction of water inside the water pump, so as to ensure the normal operation of the water pump. Therefore, the installation position of the check valve can be divided into two situations: before or after the water pump.

One is installed at the end of the vertical suction pipe in front of the water pump, also known as the bottom valve. The purpose is to fill the pump with primary water without pumping primary water. When there is no water in the pump and the suction pipe in front of the pump, the pump can only idle and can not pump water, so the pump must be filled with water to pump water.

The installation of this non return check valve is a method above the liquid level, also known as negative pressure method. The other is installed behind the water pump. This installation method is convenient when the liquid level is higher than the water pump. When starting and stopping the water pump, there is no need to close the water outlet valve of the water pump, especially for the main pipe water pump system to prevent backflow.

Another instruction from the bronze pressure reducing valve manufacturers is that the check valve must be installed at the outlet of the pump and in front of the outlet control valve for maintenance. Generally, the first outlet of the pump is the soft connection (shock absorber), the next is the check valve, and then the block valve.

(1) Install the check valve first and then the gate valve or butterfly valve

Advantages: it can protect the check valve, especially in parallel pumps. When one pump does not start, its outlet valve is closed, and the other pump starts, the impact force is borne by the gate valve or butterfly valve. In case of failure of the check valve, the inlet and outlet valve isolation system can be closed for repair.

(2) Install the gate valve or butterfly valve before the check valve

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

Generally speaking, due to the frequent opening and closing actions of the non return check valve, the internal connecting parts and sealing parts are easy to be damaged. In order to facilitate repair and prevent the shutdown of the whole system due to the failure of the check valve, the check valve will be installed before the outlet gate valve or butterfly valve.