Butterfly Valve

A Butterfly Valve is a quarter-turn rotational motion valve used to stop, regulate, and start the flow. It is popular because it is lightweight, requires less structural support, and is cost-effective compared to other valve types.
The "butterfly" is a metal disc mounted on a rod. When the valve is closed, the disc turns so that it completely blocks off the passageway. When fully open, the disc is rotated a quarter turn so that it allows an almost unrestricted passage of fluid. They are widely used in water treatment, chemical, and pharmaceutical industries for large pipe diameters.