A butterfly valve is a valve that isolates or regulates the flow of a fluid. The closing mechanism is a disk that rotates.
A butterfly valve is used to isolate or regulate the flow of a fluid. It can be used for a wide range of applications such as water supply, wastewater treatment, and fire protection, for chemical and fuel industries and many more. It is based on the quick shut off principle. The disc of the valve is placed in the center of the pipe which allows a rod to go through it to an actuator, on the outer side of the valve. The disc remains parallel or perpendicular to the flow. A pressure drop is introduced by the disc upon the flow even when open.
It open or closed when the disc is rotated a quarter turn and hence it is also known as a quarter-turn valve. There is a metal disc on the rod and when the valve is closed it blocks the passageway by giving it a quarter turn. This metal disc is known as a butterfly. It is the most important component of the valve.