Pneumatic Butterfly Valve

A Pneumatic butterfly valve is an industrial valve used to control the flow of various mediums (liquid, gas, or slurry) through a pipe. It combines a standard butterfly valve with a pneumatic actuator, which uses compressed air to open, close, or modulate the valve.
How it Works
The valve features a circular disc mounted on a rotating shaft. When the pneumatic actuator receives air pressure, it rotates the shaft, turning the disc.
Fully Open: The disc is parallel to the flow.
Fully Closed: The disc is perpendicular to the flow, sealing against the valve seat.
Key Components
Butterfly Valve Body: The main housing that holds the disc and seat.
Pneumatic Actuator: Mounted on top; can be "Rack and Pinion" or "Scotch Yoke" style.
Solenoid Valve: An electro-pneumatic device that controls the air flow to the actuator.
Limit Switch Box: Provides a signal to the control room indicating if the valve is open or closed.
Positioner (Optional): Used if the valve needs to be partially opened (e.g., 50% flow) rather than just On/Off.
Advantages
Compact Design: Takes up less space than gate or ball valves.
Cost-Effective: Generally more affordable, especially in larger sizes.
Fast Operation: Pneumatic actuation allows for quick opening and closing cycles.
Low Maintenance: Fewer moving parts compared to other valve types.