Butterfly Valve Pneumatic Actuator

pneumatic actuator
A pneumatic actuator converts energy (in the form of compressed air, typically) into motion. The motion can be rotary or linear, depending on the type of actuator.
System that is pneumatically activated to open or close a valve.
An air operated mechanical device used to open and close or modulate a valve. The actuator, which is mounted to the valve by a bracket and coupled to the stem, is designed to convert air pressure into mechanical force sufficient to operate the valve.

butterfly valve
A valve consisting of a disk rotating on an axis across the diameter of a pipe to regulate the flow, as in the throttles of many engines
A butterfly valve is a valve which can be used for isolating or regulating flow. The closing mechanism takes the form of a disk. Operation is similar to that of a ball valve, which allows for quick shut off.
A valve consisting of a pair of semicircular plates that are attached to a spindle across a pipe and hinged to allow flow only one way
a valve in a carburetor that consists of a disc that turns and acts as a throttle
(Butterfly Valves) A valve consisting of a cylindrical body with a rotating vane to control flow. Tight Shutoff is obtained by an elastomer body liner into which the vane seats.