Butterfly valve means the valve has a shape look like a butterfly, actually the butterfly valve has a centric line through it, and control by a shaft going through the disc and drive it open just like a wing of butterfly, that is why it is called butterfly valve.

Butterfly valve has a relatively simple constructionand it is one kind of quarter-turn rotational motion valves. It closes when the shaft rotates the disc by a quarter turn to a position perpendicular to the flow direction. When the valve opens, the disk is rotated back to allow the flow passing the port smoothly.Butterfly valves are used for on-off or modulating services and are popular due to their light weight, small installation footprint, lower costs, quick operation and availability in very large sizes. Besides the on-off function, the butterfly valve is often used to regulate the flow. However, we do not recommend this, as it may damage the valve disc and have a negative effect on the sealing properties.

There are several regular types of butterfly valves:
Based on the disc closure design: Concentric Butterfly Valve and Eccentric Butterfly Valve, the eccentric Butterfly Valve can be classified into Single-Offset, Double Offset, Triple Offset.
Based on the end connection in the piping system: Lug type butterfly valve, Wafer Type butterfly valve, Flanged Butterfly Valve, Butt-welded Butterfly Valve.
Based on Seat Material: Soft Seated butterfly valve, Metal Seated butterfly valve(also called hard seal butterfly valve).

Fanged Butterfly Valve

Butterfly Valve

Butterfly Valve Drawing