Butterfly Valves are Bi-Directional Quick Shut Off Valves and are available in Lug or Wafer or Double Flanged Type in Various material combinations for use in Residential and Commercial Buildings.
A butterfly valve is a quarter-turn rotational motion valve, which is used to stop, regulate, and start the flow. Butterfly valves are easy and fast to open. A 90-degree rotation of the handle provides a complete closure or opening of the valve. Large Butterfly valves are usually equipped with a so-called gearbox, where the handwheel by gears is connected to the stem. By this, the operation of the valve is simplified but at the expense of speed. Butterfly valves have a short circular body, a round disc, metal-to-metal or soft seats, top and bottom shaft bearings, and a stuffing box. The construction of a butterfly valve body varies. A commonly used design is the wafer type which fits between two flanges. Another type is the lug wafer design which is held in place between two flanges by bolts that join the two flanges and pass-through holes in the valve’s outer casing. Butterfly valves are also available with flanged, threaded and butt welding ends, but they are not used often.
These valves have many advantages over the gate, globe, plug, and ball valves, especially for large valve applications. Savings in weight, space, and cost are the most obvious advantages. The maintenance costs are usually low s there are a minimal number of moving parts and there are no pockets to trap fluids. These types of valves are especially well-suited for the handling of large flows of liquids or gases at relatively low pressures and for the handling of slurries or liquids with large amounts of suspended solids. They are built on the principle of a pipe damper. The flow control element is a disk of approximately the same diameter as the inside diameter of the adjoining pipe, which rotates on either a vertical or horizontal axis. When the disk lies parallel to the piping run, the valve is fully opened. The valve is shut when the disk approaches the perpendicular position. Intermediate positions, for throttling purposes, can be secured in place by handle-locking devices.
The stoppage of flow is accomplished by the valve disk sealing against a seat that is on the inside diameter periphery of the valve body. Many butterfly valves have an elastomeric seat against which the disk seals. Other butterfly valves have a seal ring arrangement which uses a clamp-ring and backing-ring on a serrated edge rubber ring. This design prevents extrusion of the O-rings.
Typical services include; hot and cold water, HVAC, steam, compressed air, gas, and other general utility services.