Pneumatically actuated valves, or air-operated valves, are valves that use compressed air to actuate (open, close, or modulate) the valve mechanism. These are widely used in industrial settings where fast, reliable, and safe actuation is needed—especially in hazardous environments where electricity could pose a risk.
Key Components
- Valve Body: The mechanical part that controls fluid flow (e.g., ball, butterfly, diaphragm, or globe valve).
- Pneumatic Actuator: Converts air pressure into mechanical motion.
- Control Accessories:
- Solenoid valves (to direct compressed air)
- Positioners (for modulating control)
- Limit switches and sensors
Types of Pneumatic Actuators
- Single-Acting (Spring Return):
- Air pressure opens or closes the valve, and a spring returns it to its original position.
- Useful for fail-safe operation.
2. Double-Acting:
- Air pressure is used both to open and to close the valve.
- No spring return; better for precise control and larger valves.
Valve Types Often Paired with Pneumatic Actuators
- Ball Valves
- Butterfly Valves
- Diaphragm Valves
- Globe Valves
- Plug Valves
Advantages
- Fast actuation (open/close in milliseconds to seconds)
- Intrinsically safe for hazardous environments (no electrical spark risk)
- High force output in a compact form
- Lower cost for high-speed operations in large systems
Disadvantages
- Requires a compressed air supply (and associated maintenance)
- Noisy compared to electric actuation
- Less precise unless paired with positioners
- Complex setup with tubing and control valves
Common Applications
- Chemical and petrochemical processing
- Pharmaceutical manufacturing
- Food and beverage plants
- Water and wastewater treatment
- Power plants
- Bulk material handling