Check valves can be classified into various types based on their structural form and operating principles; the most common types include the following:
Lift Check Valve: Divided into vertical and horizontal configurations, in which the valve disc slides along the vertical centerline of the valve body.
Swing Check Valve: Features a disc-shaped valve element that rotates around a pivot pin positioned within the valve seat passage; this type is suitable for large-diameter applications characterized by low flow velocities and infrequent changes in flow direction.
Butterfly Check Valve: A check valve in which the disc rotates around a hinge pin located within the valve seat; it features a simple structure but can only be installed in horizontal pipelines.
Furthermore, in terms of connection methods, check valves can be categorized into four types: threaded connections, flanged connections, welded connections, and wafer-style connections.