Shanghai Shenyin Valve Co., Ltd.

A butterfly valve is a type of flow control device, typically used to regulate a fluid flowing through a section of pipe. The valve is similar in operation to a ball valve. A flat circular plate is positioned in the center of the pipe. The plate has a rod through it connected to a handle on the outside of the valve. Rotating the handle turns the plate either parallel or perpendicular to the flow. Unlike a ball valve, the plate is always present within the flow, therefore a pressure drop is always induced in the flow regardless of valve position.

There are three types of butterfly valve:

Resilient butterfly valve which has a flexible rubber seat. Working pressure up to 1.6 megapascals (MPa)/232 pounds per square inch (PSI)
High performance butterfly valve which is usually double eccentric in design . Working pressure up to 5.0 MPa/725 PSI
Tricentric butterfly valve which is usually with metal seated design. Working pressure up to 10.0 MPa/1450 PSI
Butterfly valves are widely used in water distribution and waste water processing (not recommended, as the debris may block the operation of the disc). Butterfly valves can come in two body types, affecting installation and maintenance: lugged or wafer. Wafer style valves are more common. They are typically installed between two flanges using bolts or studs and nuts. Lug style valves are also installed between two flanges but with a separate set of bolts for each flange. The lug style setup makes it possible to remove one side of the piping while the other remains intact.

An additional application is found within the exhaust system of automobiles. By incorporating a butterfly valve in the exhaust system, it is possible to control the backpressure and noise output from the muffler and catalytic converter. When in a closed position, the valve increases the amount of back pressure produced and suppresses noise. The angle of valve can be controlled in a variety of ways, including manual control, vacuum control, as well as being tired directly to the throttle.