Piston Check Valves:

A piston check valve, described in Figure, is necessary a lift check valve. It has a dashpot consisting of a piston and cylinder which gives a cushioning effect during operation. Since, by the similarity within design to lift check valves, flow characteristics by a piston check valve are essentially the similar as through a lift check valve.

Figure: Piston Check Valve

Installation is the similar as for a lift check in which the flow must enter from under the seat. Construction of the disk and seat of a piston check valve is the similar as for lift check valves. Piston check valves are used mainly in conjunction along with globe and angle valves in piping systems experiencing extremely often changes in flow direction. Valves of these categories are used on steam, water, and air systems.