Butterfly Valves

A butterfly valve is a valve which can be used for isolating or regulating flow. The closing mechanism takes the form of a disc. Operation is similar to that of a ball valve, which allows for quick shut off. Butterfly valves are generally favored because they are lower in cost to other valve designs as well as being lighter in weight, meaning less support is required. The disc is positioned in the center of the pipe, passing through the disc is a rod connected to an actuator on the outside of the valve. Rotating the actuator turns the disc either parallel or perpendicular to the flow. Unlike a ball valve, the disc is always present within the flow, therefore a pressure drop is always induced in the flow, regardless of valve position. A butterfly valve is from a family of valves called quarter-turn valves. The "butterfly" is a metal disc mounted on a rod. When the valve is closed, the disc is turned so that it completely blocks off the passageway. When the valve is fully open, the disc is rotated a quarter turn so that it allows an almost unrestricted passage of the fluid. The valve may also be opened incrementally to throttle flow. We stock Wafer Pattern with Cast Iron or Stainless Steel Body, and Lugged with Ductile Iron, Carbon Steel or Stainless Steel Body. The size range we stock is 1 1/2" to 20". We stock a disc materials such as Aluminiume Bronze, Stainless Steel and Nickel Plated Dutile Iron, the liners we keep are EPDM, NBR, PTFE on EPDM, Silicone, VITON. Wafer-style butterfly valves The wafer style butterfly valve is designed to maintain a seal against bi-directional pressure differential to prevent backflow in systems designed for unidirectional flow. It accomplishes this with a tightly fitting seal; i.e., gasket, o-ring, precision machined, and a flat valve face on the upstream and downstream sides of the valve. Lug-style butterfly valve Lug-style valves have threaded inserts at both sides of the valve body. This allows them to be installed into a system using two sets of bolts and no nuts. The valve is installed between two flanges using a separate set of bolts for each flange. This setup permits either side of the piping system to be disconnected without disturbing the other side. A lug-style butterfly valve used in dead end service generally has a reduced pressure rating.