Butterfly Valve

A Butterfly valve is a quarter-turn rotational motion valve that is used to stop, start and regulate flow. They are constructed of a short, circular body, a round disc, typically with soft seats, top and bottom shaft bearings, and a stuffing box. Butterfly valves are available with butt weld, flanged, grooved, threaded, socket weld and tri-clamp (tri-clover) ends. The most commonly used design is the wafer type, which fits between two flanges. A wafer, or disk, which is approximately the same diameter as the inside diameter of the adjoining pipe or tube, rotates on either a vertical or horizontal axis. The valve is fully open when the handle is turned and the disc is rotated a quarter turn, allowing unrestricted flow. When the valve is closed, the handle is turned so the disc completely blocks the passageway. Butterfly valves can also be opened incrementally to control flow. As the name suggests, a lug type Butterfly valve has lugs that are used to mount the valve to a flange on the end of a section of pipe. Lugs are cast on the valve, with tapped holes that match the bolt pattern for the size and pressure classification of the flange. Bolts are passed through the flange holes and are threaded into tapped holes of the lug. While smaller Butterfly valves are typically operated with a pull or trigger handle, large Butterfly valves are usually equipped with a gearbox and handwheel mechanically operating gears connected to the stem. Actuation may be required. Butterfly valves are well-suited for handling large flows of liquids or gases at relatively low pressures, as well as for slurries and liquids with large amounts of suspended solids. Other applications include vacuum service, high-pressure / high-temperature water and steam services, cooling water, air and gases. Their weight, space, and cost are clear advantages over other types of valves, and maintenance is relatively easy due to the minimal number of moving parts. James Duva, Inc. offers a full line of Butterfly Valves, in many material grades and pressure classes, with or without actuation, built by manufacturers you trust.