Which statement best describes the function of a pneumatic filter?

• A. It cools the air
• B. It removes water from the air
• C. It removes contaminants from the air stream
• D. It increases pressure

Answer: (C)

A pneumatic filter cleans the compressed air by removing contaminants from the air stream. It traps particles like dust, dirt, rust, and oil aerosols that can enter the system, protecting seals, valves, and cylinders and helping keep actuators running smoothly and reliably. The other functions aren’t what a filter does: cooling the air is handled by cooling devices or dryers, removing water is mainly done by moisture separators or air dryers (though some filters can remove small liquid droplets), and increasing pressure is accomplished by the compressor or pressure regulators, not the filter.