According to the definition of the British Association of Valves and Actuators, a butterfly valve is "a valve whose orifice rotates at a right angle to the direction of the fluid around an axis. In the open position, the fluid bypasses the valve of the orifice." In other words, the butterfly valve consists of a circle The valve disc or plate is formed in a shape, and the valve stem passes through the middle or is attached in an offset position. When opened, the valve flap rotates 90 degrees in the valve hole, aligns with the fluid, and creates an almost unrestricted flow path. Like the ball valve, the butterfly valve can be quickly closed by rotating 90 degrees. What do we know about it? How does it work? You will find it after reading this article.