Check valve refers to rely on the flow of the media itself and automatic open, closed disc, used to prevent the return of the medium of the valve, also known as the reverse check valve, one-way valve, countercurrent valves, and back pressure valve. The check valve belongs to an automatic valve, its main function is to prevent the media backflow, prevent the pump and drive motor reversal, as well as the release of the container media. The check valve can also be used to give the pressure in which it may rise to a secondary system that exceeds the system pressure to provide supply to the pipe road.
Check valve mainly can be divided into swing check valve (rotation of the center of gravity) and lift check valve (moving along the axis).
The function of the check valve is to allow only the medium to flow in one direction and to prevent the flow in the opposite direction. Usually this valve is automatically operated, in one direction flowing fluid pressure action, the disc opens, the flow in the opposite direction, by the fluid pressure and the valve flap of the self-weight of the valve seat, thereby cutting off the flow.