The Butterfly valve is used to regulate and control, throttle the flow. They are featured by a fast operation and low-pressure drop. To make an open position from the closed, it requires only a quarter turn. Wafer, lug, Single-Flange, Flange are the regular types of butterfly valves. A valve consisting of a rotating circular plate or a pair of hinged semi-circular plates, attached to a transverse spindle and mounted inside a pipe in order to regulate or prevent flow.