1. Swing Check Valve: The disc of swing Check Valve is disc-shaped and rotates around the axis of the seat passage. Because the passage inside the valve is streamlined, the flow resistance is smaller than that of lift Check Valve. It is suitable for large caliber occasions with low flow rate and unstable flow, but it is not suitable for pulsating flow, and its sealing performance is inferior to that of lift Check Valve. Swing check valves are divided into three types: single-lobe, double-lobe and multi-half. These three types are mainly divided according to the valve caliber. The purpose is to prevent the hydraulic impact when the medium stops flowing or backflows.
2. Lift check valve: A check valve whose disc slides along the vertical center line of the valve body. Lift check valve can only be installed in horizontal pipeline. The disc can be used on high-pressure small caliber check valve with a ball. Lift check valves have the same body shape as globe valves (which can be used as globe valves), so their fluid resistance coefficient is larger. The structure of the valve is similar to that of the globe valve, and the body and disc are in phase with the globe valve.
Silent check valve
Silent check valve
Same. The upper part of the disc and the lower part of the cover are machined with a guide sleeve. The guide sleeve of the disc can rise and fall freely in the guide plate of the valve. When the medium flows downstream, the disc opens by the medium thrust. When the medium stops flowing, the disc falls on the seat by the sag to prevent the medium countercurrent. The direction of medium inlet and outlet passage of straight-through lifting check valve is perpendicular to that of seat passage; the direction of medium inlet and outlet passage of vertical lifting check valve is the same as that of seat passage, and its flow resistance is smaller than that of straight-through check valve.
Disc Check Valves: Check valves with discs revolving around pins in the seat. The disc check valve has simple structure, can only be installed in horizontal pipeline, and its sealing performance is poor.
Pipeline Check Valves: Valves with discs sliding along the center line of the body. Pipeline check valve is a new kind of valve. It has small volume, light weight and good processing technology. It is one of the development directions of check valve. But the coefficient of fluid resistance is slightly larger than that of swing check valve.
Fifth, pressure check valve: This valve is used as boiler feed water and steam cut-off valve, it has a lift check valve and globe valve or corner valve integrated function.
In addition, there are some check valves not suitable for pump outlet installation, such as bottom valve, spring type, Y type, etc.