What is a check valve? What are the functions?

Check valve (also known as check valve) refers to the valve that automatically opens and closes the disc depending on the flow of the medium itself to prevent the medium from flowing backwards, also known as check valve, one-way valve, reverse flow valve and back pressure valve. Check valve is an automatic valve, its main function is to prevent the medium from flowing backwards, prevent the pump and driving motor from reversing, and release the medium in the container. Check valves can also be used in pipes supplying water to auxiliary systems, in which the pressure may rise above the system pressure. Check valves can be mainly divided into swing check valves (rotating according to the center of gravity) and lifting check valves (moving along the axis).

The disc of the check valve is disc-shaped and rotates around the axis of rotation of the seat channel. Because the flow channel in the valve is streamlined, the flow resistance is smaller than that of the butterfly valve. It is suitable for large-caliber occasions with low flow and constant flow, but it is not suitable for pulsating flow, and its sealing performance is not as good as that of lifting type. Butterfly check valves are divided into three types: single disc, double disc and multiple disc. These three types are mainly divided according to the valve caliber, in order to prevent the medium from cutting off or flowing back and weaken the hydraulic impact.

Check valve: A check valve whose disc slides along the vertical center line of the valve body. The silencing check valve can only be installed on the horizontal pipeline, and the disc can be a ball on the high-pressure small-caliber check valve. The shape of the valve body of the silencing check valve is the same as that of the stop valve (generally it can be used together with the stop valve), so its fluid resistance coefficient is large. Its structure is similar to the cut-off valve, and the valve body and disc are the same as the cut-off valve. The upper part of the valve disc and the lower part of the valve cover are provided with guide sleeves, which can freely rise and fall in the guide sleeves of the valve lamp. When the medium flows downstream, the valve disc is opened by the thrust of the medium, and when the medium stops flowing, the valve disc falls vertically on the valve seat to prevent the medium from flowing backwards. The medium inlet and outlet channel direction of the straight butterfly check valve is perpendicular to the channel direction of the valve seat; Vertical lifting check valve, the direction of medium inlet and outlet channel is the same as that of valve seat channel, and the flow resistance is smaller than that of straight-through type.