WAFER CHECK VALVES: Check Valves are one-way flow valve or self-actuating valves that minimize the reversal of fluid flow in a piping system and pump components. Check Valves are opened by the force of fluid in motion,flowing in one direction. They are commonly installed in pipeline system to prevent back-flow. If for some reasons the flow turns, the valve will close to protect the piping system and components from water hammer. Check Valves are classified as one-way directional control valves. Check valve may be installed independently in a line to allow one-direction flow, and they are available in different standard and designs.