Check valve is a kind of valve that depends on flow of medium to open or close disc.
Check valve is used to avoid back flow of valve.
Based on structure, check valve can be classified into lift check valve, swing check valve, butterfly check valve, pipe valve.
1.
Lift check valve: The disc of lift check valve can slide along vertical center line of body. Lift check valve can be only used for horizontal pipeline. The disc of high pressure small caliber check valve uses ball. The shape of body of lift check valve is similar to globe valve. For that, resistance coefficient of fluid is large.
2.
Swing check valve: Disc rotates around the pin roll outside base. Swing check valve is one of the most common used check valves.
3. Butterfly check valve: Disc rotates around the pin roll inside base. Butterfly check valve has simple structure and it can be only used for horizontal pipeline, having bad sealing.
4. Pipe check valve: Disc slides along the centre line of body. Pipe line is a new type valve. It has small volume, light weight and excellent manufacturability. Pipe line is one of development directions for check valve. However, resistance coefficient of pipe check valve is larger than swing check valve.
