SUPREME AQUA GOLD MOULDED PIPE FITTINGS SWING CHECK VALVE - SCH80 SWING CHECK VALVE (Size-50mm) - The valve body, seat, and disc that are connected to the hinge make up the swing check valve. As the flow rate reaches a certain level, the disc rotates to a horizontal position to allow for onward flow. When the flow is stopped, it returns to the valve seat to stop backflow.