Composition and Characteristics of Swing Type Check Valve

The swing type check valve, also known as a one-way valve or a check valve, is used to prevent the backflow of the medium in the pipeline. The valve that opens or closes by itself by the flow and force of the medium to prevent the backflow of the medium is called a check valve. Industrial check valves belong to the automatic valve category, which are mainly used on pipelines where the medium flows in one direction, and only allow the medium to flow in one direction to prevent accidents. This type of valve should generally be installed horizontally in the pipeline.

The swing type check valve is a check valve in which the valve flap rotates around the rocker shaft in the body cavity. The opening and closing principle of the swing type check valve is the same as that of the lift check valve. It also depends on the action of fluid pressure and the self-weight of the valve disc. The inlet direction of the valve should be on the side that can impact the rotation of the disc. The closing part of the swing type check valve is a disc or disc with the same diameter as the pipeline, which is suspended in the valve cavity. When the fluid is flowing forward, the disc opens under the action of the fluid pressure. It closes under the action of its own weight and the pressure of the countercurrent fluid. MstnLand, a China check valves exporter, exports various kinds of high performance check valves. 

1. Swing type check valve consists of valve body, valve cover, valve disc and rocker

The valve disc is disc-shaped and rotates around the pin shaft outside the valve seat channel. The channel in the valve is streamlined, and the flow resistance is smaller than that of the straight-through lift check valve, which is suitable for large-diameter pipelines. But at low pressure, its sealing performance is not as good as the lift check valve. In order to improve the sealing performance, an auxiliary spring or a weight structure can be used to assist the sealing.

Due to the weight of the disc, when the swing type check valve is opened, the resistance to the fluid is relatively large. In addition, because the valve flap is suspended in the fluid, the fluid can be turbulent. This also shows that the fluid pressure drop across the swing type check valve is greater than that across other types of check valves. When the flow direction changes suddenly, the valve disc will be violently closed on the valve seat, which will cause great wear on the valve seat and produce water hammer along the pipeline. To overcome this problem, a damping device can be installed on the valve disc, and metal seat reduces seat wear.

2. Main features of swing type check valve

The swing type check valve adopts a built-in rocker arm swing 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 sealing ring used in the middle flange, there is no leakage point as a whole, preventing the possibility of valve leakage. The connection between the rocker arm and the disc of the swing type check valve adopts a spherical connection structure, so that the disc has a certain degree of freedom in the range of 360 degrees, and has appropriate micro-position compensation. The swing type check valve developed and produced by the manufacturer has been widely used in chemical, metallurgy, pharmaceutical and other fields.

Ordinary swing type check valves have a flap-like closure that rotates around a pin outside the valve seat. The travel of the disc from the fully open to the closed position is greater than that of most lift check valves. In addition, the rotation of the disc around the pin is not easily hindered by dirt and viscous media.

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