1. The disc of the fluorine-lined check valve is in the shape of a disc and rotates around the shaft of the valve seat channel. Because the inner channel of the valve is streamlined, the flow resistance is smaller than that of the butterfly check valve. It is suitable for low flow rate and poor flow. It is suitable for large-diameter occasions with frequent changes, but it is not suitable for pulsating flow, and its sealing performance is not as good as that of lifting type. Butterfly check valve is divided into three types: single-lobe type, double-lobe type and multi-half type. These three forms are mainly divided according to the diameter of the valve.

2. Fluorine-lined check valve: a check valve whose disc slides along the vertical centerline of the valve body. The muffler check valve can only be installed on horizontal pipelines, preferably on vertical pipelines. In high-pressure small-diameter check valves The upper disc can be a ball. The shape of the valve body of the muffler check valve is the same as that of the globe valve (it can be used in common with the globe valve), so its fluid resistance coefficient is larger. Its structure is similar to the globe valve, and the valve body and disc are the same as the globe valve. The upper part of the valve disc and the lower part of the valve cover are machined with guide sleeves. The valve disc guide can be freely lifted and lowered in the valve guide. When the medium flows downstream, the valve disc is opened by the thrust of the medium. It falls vertically on the valve seat to prevent the reverse flow of the medium. The direction of the medium inlet and outlet channels of the straight-through butterfly check valve is perpendicular to the direction of the valve seat channel; the vertical lift 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 type.

3. Fluorine-lined check valve: a check valve in which the disc rotates around the pin shaft in the valve seat. The disc check valve has a simple structure and can only be installed on horizontal pipelines with good sealing performance.

4. Fluorine-lined check valve: a valve in which the disc slides along the centerline of the valve body. Pipeline check valve is a new valve. It is small in size, light in weight and good in processing technology. It is one of the development directions of check valve. However, the fluid resistance coefficient is slightly larger than that of the swing check valve.

5. Compression check valve: This valve is used as a valve for boiler feed water and steam cut-off. It has the comprehensive function of a lift check valve and a globe valve or an angle valve.

In addition, there are some check valves that are not suitable for pump outlet installation, such as bottom valve, spring type, Y-type and other check valves.