What type of actuator converts pneumatic pressure into linear valve movement?

• A. Pneumatic diaphragm actuator
• B. Electric actuator
• C. Hydraulic actuator
• D. Magnetic actuator

Answer: (A)

Pneumatic diaphragm actuators are designed to take compressed air and turn that pressure into straight-line (linear) movement to operate a valve stem. When air pressure pushes on the flexible diaphragm, the diaphragm deforms and transfers that motion to the attached stem, producing the linear actuation needed to open or close the valve. This type of actuator is common for valve control because it provides quick, simple, and reliable linear movement and can be paired with springs for safe fail‑position when the air supply is lost.

Electric actuators convert electrical energy into motion, not pneumatic pressure. Hydraulic actuators use pressurized liquid to generate force and movement, which is a different medium and often for higher force applications. Magnetic actuators rely on magnetic forces rather than pneumatic pressure to move.