In a pneumatic system, which line conveys air from the supply to the actuator?

• A. Actuator line
• B. Supply line
• C. Exhaust line
• D. Control line

Answer: (A)

In pneumatic systems, each line has a specific role: the supply line brings compressed air from the compressor into the system, the control (or pilot) line directs signals to valves to open or close, the actuator line carries air from the valve to the actuator to produce motion, and the exhaust line vents air to the atmosphere when air is released. The line that actually moves air from the supply to the actuator is the actuator line. When a valve is commanded to extend or retract a cylinder, air travels from the supply through the system into the valve, and the valve routes that air through the actuator line to the actuator, creating movement. The exhaust line would only vent air away from the actuator on the opposite side or when releasing pressure.