2 Way Ball Valves/3 Way Ball Valves Wholesalers introduces the function and selection of outlet check valve of centrifugal pump:

1. Selection of check valve for pump outlet check valve
In general pumping station engineering, the following principles should be followed for the selection of the pump outlet check valve;

For pipelines with a small diameter of the pump outlet pipeline, that is, when DN ≤ 50mm, a lift check valve should be selected.

For pipelines with a diameter of DN>50mm at the pump outlet, a swing check valve should be selected. The swing check valve can be installed horizontally or vertically. The disc of swing check valve rotates around the rotating shaft, and its fluid resistance is generally smaller than that of lift check valve. It is suitable for occasions with larger diameters, and the installation position is not limited. It is usually installed in horizontal pipelines. It is suitable for use with for larger diameters. According to the number of valve discs, it can be divided into three types: single-lobe swing type, double-lobe swing type and multi-lobe swing type. Single flap swing check valve is generally used in the occasions of medium caliber. When a single flap swing check valve is used for large-diameter pipelines, in order to reduce the water hammer pressure, it is best to use a slow-closing check valve that can reduce the water hammer pressure. Double flap swing check valve is suitable for large and medium diameter pipelines. Wafer double flap swing check valve is a relatively fast check valve with small structure and light weight; multi flap swing check valve is suitable for large diameter pipelines.

2. Installation of pump outlet check valve

① Swing check valves are generally installed on horizontal pipelines: for check valves with a diameter of DN~80mm, they can also be installed on vertical or upward inclined pipelines.

② The straight-through lift check valve should be installed on the horizontal pipeline; the vertical lift check valve must be installed on the vertical pipeline, and the medium flows from bottom to top.

③ Since the check valve is easy to be damaged, a check valve should be installed near the pump outlet, and a cut-off valve (generally a ball valve or gate valve) should be installed on the upper part of the check valve to facilitate maintenance.

④ To facilitate pressure relief before the check valve is disassembled, if the check valve itself does not have a purge valve, a purge valve for pressure relief should be installed between the check valve and the shut-off valve.

3. Protective measures to prevent hydraulic shock from damaging the sealing surface of the check valve

The setting of the check valve plays a role in preventing the backflow of the material and preventing the pump impeller from being subjected to liquid shock. However, as far as the check valve itself is concerned, improper setting will cause the sudden impact of the valve disc on the valve seat caused by water hammer, and damage the sealing surface of the check valve. Therefore, several protective measures should be taken.

1. For the swing check valve with a pump outlet set > 80mm, it should be installed horizontally to reduce the valve disc seat and the resulting impact.

2. For the pipeline with the diameter of the check valve at the pump outlet >=150mm, a bypass should be set up before and after the check valve to prevent the pressure before the valve from rising too high and causing damage to the sealing surface of the check valve.

3. For pipelines with high pressure at the starting point and the end point of the pump discharge pipeline, if bypass is not allowed, the following measures can be taken.

Through the above introduction, Mining Ball Valves Suppliers hopes that you can simply refer to the content of this article in future use.