Which component in a pneumatic system uses a screw adjustment to set flow?

• A. Quick exhaust valve
• B. Regulator
• C. Pneumatic needle valve
• D. Filter

Answer: (C)

Flow is controlled by metering devices, and a pneumatic needle valve is designed for precise flow adjustment. It uses a small screw to move a tapered needle into or out of a conical seat, narrowing or widening the passage and giving very fine control over how much air can pass. Because of the fine-thread screw, you can make tiny changes to the flow rate, which is essential when you need slow, careful metering or throttling in a circuit. The other components have different roles: a quick exhaust valve speeds up venting of air from a line or cylinder, not a regulated flow; a regulator sets and maintains a desired pressure rather than directly controlling flow rate; and a filter removes contaminants without affecting how much air moves through the system.