Butterfly Valves

A butterfly valve controls flow using a disc that rotates in the pipe. The disc turns 90 degrees from fully closed to fully open. A shaft through the center turns the disc.

Function

The disc rotates to control how much fluid can pass through. When the disc is parallel to flow, the valve is fully open. When the disc is across the pipe, it blocks the flow completely.

Main Types

Resilient Seated Butterfly Valves have a rubber seal around the disc. They give tight shutoff and work well in water systems.

High Performance Butterfly Valves use metal seats. They handle high temperatures and pressures in industrial processes.

Triple Offset Butterfly Valves have special geometry that reduces seat wear. They provide very tight shutoff for demanding applications.

Uses

Butterfly valves control flow in large pipes where space is limited. They work in water treatment, power plants, and industrial processes. They are good for both on-off service and flow control.

Important Facts

The disc always stays in the flow path, causing some pressure loss even when fully open. Large valves need less force to operate than other valve types of the same size. The shaft seals must be maintained to prevent leaks. Most types need a seat on the disc or in the body to seal properly.