A butterfly valve is a valve used for flow regulation in which the disc takes the form of disk. Operation is similar to that of a ball valve. A plate or disc is positioned in the center of the pipe. The disc has a rod passing through it that is connected to an actuator on the outside of the valve. Rotating the actuator turns the disc either parallel or perpendicular to the flow. Unlike a ball valve, the disc is always present within the flow, therefore a pressure drop is always induced in the flow, regardless of valve position. A butterfly valve is from a family of valves called quarter-turn valves. The "butterfly" is a metal disc mounted on a rod. When the valve is closed, the disc is turned so that it completely blocks off the passageway. When the valve is fully open, the disc is rotated a quarter turn so that it allows an almost unrestricted passage of the fluid. The valve may also be opened incrementally to throttle flow.

Данное издание не является оригинальным. Книга печатается по технологии принт-он-деманд после получения заказа.