Which option is NOT a primary function of a hydraulic valve?

• A. Open/Close flow path
• B. Direct flow
• C. Regulate pressure
• D. Filter contaminants in the fluid

Answer: (D)

Hydraulic valves are used to control how fluid moves and under what pressure. The main jobs are to open and close the flow path, directing the fluid to the correct port or branch, and regulating pressure by throttling or relieving flow as needed. Filtering contaminants, while essential for system health, is done by filtration devices rather than by the valve itself. A filter sits in the fluid path (often in the reservoir or as an inline element) to remove particles before the fluid reaches sensitive components. So the option about filtering contaminants isn’t a primary valve function, even though keeping fluid clean is crucial for system reliability.