A pneumatic valve is powered by what?

• A. Air pressure
• B. Electric current
• C. Hydraulic fluid pressure
• D. Manual hand wheel

Answer: (A)

Pneumatic valves get their actuation energy from compressed air. When air at pressure is admitted into the actuator chamber, it pushes a piston or diaphragm inside the valve, moving the valve element to open or close. The energy source is the air pressure stored in the system, not electricity or hydraulic fluid. Electric current would power an electric actuator or a solenoid that controls the air flow, but the force that moves the valve itself comes from the compressed air. Hydraulic systems use fluid pressure in a different medium, and a manual hand wheel relies on human effort rather than the pneumatic energy source.