The role and classification of check valve

The check valve is an automatic valve, and its main function is to prevent the medium from flowing backward, to prevent the pump and the drive motor from reversing, and to release the medium from the container. Check valves can also be used to supply lines to auxiliary systems whose pressure may rise above the system pressure.

Check valve classification

Check valve can be divided according to its structure and installation:

Swing check valve: The disc of the swing check valve is disc-shaped and rotates around the rotation axis of the valve seat channel. Because the channel inside the valve is streamlined, the flow resistance is smaller than that of the lift check valve It is suitable for large-caliber occasions with low flow rate and infrequent flow, but it is not suitable for pulsating flow, and its sealing performance is not as good as that of lifting type. Swing check valve is divided into three types: single, double and multi-lobe. These three types are mainly divided according to the valve diameter. The purpose is to prevent the hydraulic shock when the medium stops flowing or flows backward.

Lift check valve: Check valve with valve disc sliding along the vertical centerline of the valve body. Lift check valve can only be installed on horizontal pipelines. On high-pressure small-diameter check valves, the disc can be a ball. The shape of the valve body of the lift check valve is the same as that of the shut-off valve (common with the shut-off valve), so its fluid resistance coefficient is large. Its structure is similar to a globe valve, with the same body and disc as the globe valve. The upper part of the valve disc and the lower part of the valve cover are processed with a guide sleeve. The valve disc guide can be freely raised and lowered in the valve guide. When the medium flows, the valve disc is opened by the medium thrust. When the medium stops flowing, the valve disc is It drops down on the valve seat and plays a role in preventing the medium from flowing backward. The direction of the inlet and outlet channels of the straight-through lifting check valve is perpendicular to the direction of the valve seat channel; the vertical inlet and outlet check valve has the same direction of the medium inlet and outlet channels as the valve seat channel, and its flow resistance is smaller than that of the straight-through valve.