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How swing check valve works

Author: Site Editor     Publish Time: 2019-03-04      Origin: Site

The working principle of the swing check valve is somewhat similar to the shut-off valve. The passage of the fluid through the lift check valve is also narrow, so the pressure through the lift check valve is larger than that of the swing check valve, and the swing is started. The flow rate of the check valve is limited.


Casting Steel WCB Flanged Drain Swing Check Valve

List of content for this article:

1.   What is swing check valve ?

2.   What is the purpose?

3.   What is the structure?


What is swing check valve ?

The swing check valve is also called a check valve or a check valve, and its function is to prevent the medium in the pipeline from flowing backward. The valve of the opening and closing member is opened or closed by the flow of the medium and the force to prevent the back flow of the medium from being called a check valve. The check valve is an automatic valve type, mainly used for the one-way flow of the medium, only allowing the medium to flow in one direction to prevent accidents. This type of valve should be installed horizontally in the pipeline.


1. The principle of opening and closing of the swing-type check valve is the same as that of the lift check valve. It is also operated by the fluid pressure and the self-weight of the valve disc. The difference is that the opening and closing mode of the flap is a rotary motion instead of moving up and down. The inlet direction of the fluid should be on the side that can impact the flap.


2. The closing member of the swing-type check valve is a valve flap or disc corresponding to the diameter of the pipe, suspended in the valve cavity, and the valve flap is opened under the action of fluid pressure when the fluid is flowing forward, and the valve is lowered when the pressure is lowered. The flap is closed by the pressure of its own weight and counter current fluid.


3. The swing-type check valve is composed of a valve body, a valve cover, a valve flap and a rocker. The valve disc is disc-shaped and rotates around the pin shaft outside the valve seat passage. The valve channel is streamlined and has a lower flow resistance than the straight-through lift check valve. It is suitable for large diameter pipes. However, at low pressures, the sealing performance is not as good as that of the lift check valve. In order to improve the sealing performance, an auxiliary spring or a heavy hammer structure may be used to assist the sealing.


4. Due to the weight of the valve flap, when the swing check valve is opened, the resistance to the fluid is relatively large. In addition, since the valve flap is suspended in the fluid, the fluid can be turbulent. This also indicates that the fluid pressure drop through the swing check valve is greater than the pressure drop through the other form of check valve. When the flow direction changes abruptly, the valve flap will be violently closed on the valve seat, which will cause great wear of the valve seat and generate water hammer along the pipeline. To overcome this problem, a damping device can be installed on the valve flap and metal is used.


What is the purpose?

Swing check valve is suitable for nominal pressure PN1.0MPa~42.0MPa, Class150-2500; nominal diameter DN15~1200mm, NPS1/2~48; working temperature -196~540°C for various pipelines, used to prevent The media is reversed. By using different materials (WCB, CF8(M), CF3(M), 1Gr5Mo, 15CrMo1V, it can be applied to various media such as water, steam, oil, nitric acid, acetic acid, strong oxidizing medium and urea. Oil, chemical, pharmaceutical, fertilizer, electricity and other pipelines.


What is the structure?

The swing-type check valve adopts the built-in rocker arm swinging structure. All the opening and closing parts of the valve are installed inside the valve body, and do not penetrate the valve body, except for the sealing gasket and the sealing ring of the middle flange part, the whole There is no leakage point to prevent the possibility of valve leakage. The swing-type check valve has a spherical connection structure at the joint of the rocker arm and the valve flap, so that the valve flap has a certain degree of freedom within a range of 360 degrees, and has appropriate micro-position compensation. Suitable for clean media, not suitable for media containing solid particles and high viscosity


Swing check valve is also called one-way valve or check valve. Its function is to prevent medium backflow in pipeline. The opening and closing parts open or close by themselves depending on the medium flow and force to prevent the medium backflow valve is called a check valve. Check valves belong to automatic valves. They are mainly used in pipelines with one-way flow of medium. Only one-way flow of medium is allowed to prevent accidents.


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