Swing type check valve: the disc of the swing check valve is in disc shape and rotates around the shaft of the valve seat passageway. Because the internal passage of the valve is in line shape, the flow resistance is smaller than that of the lifting check valve. It is suitable for large diameter occasions with low flow rate and inconstant flow. Swing check valve is divided into single valve type, double valve type and half type three, these three forms are mainly divided by valve diameter, the purpose is to prevent the medium stop flow or reverse flow, reduce hydraulic impact. Lifting check valve: the check valve that the disc slides along the vertical center line of the valve body, lifting check valve can only be installed in the horizontal pipeline, the disc can be used in the high pressure small diameter check valve ball. The body shape of the lift check valve is the same as the globe valve (can be used with the globe valve), so its fluid resistance coefficient is large. The 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 disc and the lower part of the cover are machined with guide sleeve Jane, the guide Jane of the disc can be raised and lowered freely in the guide Jane of the valve. When the medium flows forward, the disc can be opened by the thrust of the medium. Straight lift check valve medium inlet and outlet channel direction and valve seat channel direction perpendicular; Vertical lift check valve, the medium inlet and outlet channel direction and the valve seat channel direction is the same, its flow resistance is smaller than the straight through.