Author: Site Editor Publish Time: 2019-02-13 Origin: Site
The swing check valve function is to prevent the medium in the pipeline from flowing backward. The valve of the opening and closing part 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.
Check valves are automatic valves, mainly used on pipes with one-way flow of media, allowing only the media to flow in one direction to prevent accidents. This type of valve should generally be installed horizontally in the pipeline .
Swing-type 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.
The swing-type check valve adopts the built-in rocker arm swinging structure, and all the opening and closing parts of the valve are installed inside the valve body without penetrating the valve body, except for the sealing gasket and the sealing ring of the middle flange part,There is no leak 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.
The swing check valve is a check valve for the rotary motion of the valve shaft around the rocker shaft in the body cavity. The principle of opening and closing of the swing check valve is the same as that of the lift check valve. It is also caused by the action of 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 rather than moving up and down. The direction of the entrance should be on the side that can impact the flap.
The closing part of the swing 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 flap is closed when the pressure drops. It is closed by the pressure of its own weight and counter current fluid.
The swing 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.
Due to the weight of the flap, the resistance to fluid is relatively large when the swing check valve is opened. 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.