A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways.
Isolation Valves: Ball, butterfly, diaphragm, gate, pinch, piston, and plug valves. Regulation Valves: Ball, butterfly, diaphragm, globe, needle, pinch, and plug valves. Safety Relief Valves: Pressure release and vacuum relief valves. Non-Return Valves: Swing check and lift check valves.