Wafer type check valves also known as non-return valve, back pressure valve, check valve. This type of valve is to rely on the force created by the flow of the medium itself in the line of open and close automatically, belongs to a kind of automatic valve.
    This type of valve's role is only allowed to medium flows in one direction, the direction and stop the flow. This valve is normally automatic work, in a direction of flow of fluid pressure and valve opening; In the opposite direction of fluid flow, the fluid pressure since the overlap of the disc and the disc on the seat, thereby cutting off flow.
    The stainless steel wafer check valve is belong to this type of valve, which includes swing check valve and lift check valve. Swing check valve with the humble hinge institutions, there is also a disc freely like door on the tilt of the seat surface. In order to ensure that each disc to seat the appropriate location, in valve design hinge agencies, so that the disc with enough space of a swing, and real, comprehensive, and the valve seat contact. All disc can be made from metal, can be embedded in the metal on leather, rubber, or synthetic coverage, depending on the use of performance requirements. Swing check valve in the fully open conditions, almost unimpeded fluid pressure, so the pressure drop across the valve is relatively small. Lift check valve on the disc is located in the body of the valve seat sealing surface. In addition to this check valve can be freely valve movements, like the rest of the cut-off valve, fluid pressure from the valve seat sealing surface lift, medium return led to the disc back to seat, and cut off the flow. According to the conditions of use, valve can be all-metal structure, it can also be embedded in disc shelves rubber mat or rubber ring form. Like a cut-off valve, fluid through the lift check valve channel is narrow, so the lift check valve through the pressure drop than the swing check valves are bigger, and swing check valves are very few restrictions.