1. The disc of the piston check valve is disk-shaped, the rotating shaft around the seat passage is rotated, because the inner channel of the valve is streamlined, the flow resistance is smaller than the butterfly check valve, which is suitable for the low flow rate and the large aperture of the unsteady flow, but it is not suitable for pulsating flow, and its sealing performance is less than the lifting type. Butterfly check valve is divided into single, double and most of the three kinds, these three kinds of form mainly according to the valve caliber to divide, the purpose is to prevent the medium to stop flowing or backflow, weaken the hydraulic impact.Check Valve
2, the piston check valve flap along the valve body vertical centerline sliding check valve, the internal thread check valve only installs in the horizontal pipeline, in the high pressure small caliber non-return valve the disc may use the ball. Butterfly Check Valve body shape is the same as the cut-off valve (can be used with the cut-off valve), so its fluid resistance coefficient is larger. 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 valve cover are machined with a guide sleeve. Disc-guided simple in the valve guide to the free Take-off and landing, when the media downstream, the disc by the media thrust, when the media stop, the disc from the vertical landing on the valve seat, to prevent the medium countercurrent effect. Straight-Through butterfly check valve medium inlet and outlet channel direction is perpendicular to the valve seat channel direction; vertical lift type check valve, its medium import and export channel direction is same with the valve seat channel direction, its flow resistance is smaller than the straight-through type.
3, Piston check valve: Disc around the valve seat of the pin axis rotation check valve. Disc check valve structure is simple, can only be installed on the horizontal pipe, good sealing.Check Valve
4. PISTON Check VALVE: valve that slides along valve body centerline. Pipe check valve is a new type of valve, its small size, light weight, good processing technology, is one of the development direction of check valve. But the fluid resistance coefficient is slightly larger than the swing check valve.Check Valve
5. Pressure-type check valve: This valve is used as boiler feedwater and steam cut-off valve, it has the lift type check valve and stop valve or the comprehensive function of the angle valve.Check Valve
In addition, some are not suitable for pump export installation check valve, such as bottom valve, spring type, y type check valve.