Butterfly valves can be used for a wide range of applications such as water supply, wastewater treatment, fire protection, for the chemical and oil industries, for fuel handling systems and also for applications within the power generation industry.
With the introduction of the double and triple eccentric designs, butterfly valves are more and more used also in the oil and gas industry and have started to compete with more traditional valves, as globe and ball valves.
The key component of a butterfly valve is the disc, a metal ring which is positioned at the centerline of the pipe and connected to an external actuator (manual level or actuator) via a rod.
Compared to a ball valve, the disc of a butterfly valve is always in contact with the fluid conveyed by the pipeline and creates, therefore, a pressure drop.
In the closed position, the disc blocks the bore of the valve, and, in an open position, the disc allows the passage of the fluid.
A quarter turn movement is needed to switch the valve from a fully open to a fully closed position (and such movement can be executed as quickly as for ball valves).