Butterfly valves are found throughout the fluid based applications in the process control field. They are one of many common and special types of industrial valves used to regulate fluid flow in ways that are compatible with the media being controlled and the degree of precision needed to produce the desired process outcome.
The industrial process control field benefits from a large array of valve manufacturers in pursuit of the favor and business of process operators. Operators continually seek better performance and lower life cycle costs. Manufacturers respond with increasingly improved designs.
A butterfly valve has a disc that is positioned in the fluid flow path. It rotates around a central axis, the stem, through a 90 degree arc from a position parallel to the flow direction (open) to perpendicular (closed). A critical element of a butterfly valve is the seat, where the disc seals to the body in the closed position. Seat design should provide these positive operating attributes:
- Low friction to reduce valve operating torque
- Resistance to wear
- Arrangement that provides for easy replacement
- Seal or shutoff tightness appropriate for the application