A check valve in which the disc rotates around the pin in the body cavity. Swing check valves are divided into single-disc swing check valves and double-disc swing check valves.
Usually, this type of check valve has a disc-shaped closing member that rotates around a hinge outside the valve seat. The valve disc has a large stroke from the fully open position to the closed position, but dirt and viscous media will not easily hinder its rotation. The medium flows in from the inlet end (lower side) and flows out from the outlet end (upper side). When the inlet pressure is greater than the sum of the weight of the valve disc and its flow resistance, the valve is opened. On the contrary, the valve is closed when the medium flows back. The working principle of a single-disc check valve is similar to that of a lift check valve. Check valves are often used as bottom valves in pumping devices to prevent water from flowing back. Check valves are used in combination with globe valves to provide safe isolation.
