Butterfly Valve

Butterfly valves belong to the quarter turn valve family which have a "Butterfly" disk connected to a stem and are commonly used to stop, regulate, and start flow. The disc closes when the stem rotates the disc a quarter turn to a position perpendicular to the direction of flow. When the butterfly valve opens, the disc is turned back for flow. Butterfly valves are used for on-off or modulation service and are popular for their light weight, small installation size, lower cost, fast operation, and availability in very large sizes. These valves can be operated by handles, gears or automatic actuators. Butterfly valve is easy and quick to open. 90° handle rotation provides full valve closing or opening. Large butterfly valves are usually equipped with the so-called gearbox, in which the handwheel with the gearbox is connected to the stem. This makes valve operation simpler, but at the expense of speed.