Check valves are used to prevent the reverse flow of fluid. The principle of operation of the check valve is that the valve is opened by the flow of fluid, and the valve is closed by the flow of gravity or the direction of the fluid. There are two basic types of check valves: SWING TYPE and LIFT TYPE.
The disc of the swing check valve is shaped like a disc, and a rotating shaft can make it swing along the axis of the sealing surface of the seat to open the valve. This structure has low flow resistance and is suitable for large diameter occasions. However, the sealing performance is not as good as the lifting type, and it is not suitable for frequent changes in velocity and pulsating flow. Because at this time the valve disc repeatedly hit the seat and lead to the sealing surface damage.
The lifting CHECK valve can be divided into PISTON CHECK and BALL CHECK. The latter has less flow resistance than the former. The horizontal PISTON CHECK VALVE can only be installed on the horizontal line (or on the riser when SPRINGLOADED). The BALL CHECK VALVE is available in horizontal and vertical versions.