An oil safety valve is recommended for gravity-fed oil line systems to stop oil flow if the line leaks.

• A. Gravity
• B. Pressure
• C. Vacuum
• D. Hydraulic

Answer: (A)

In gravity-fed oil line systems the flow is driven by the weight of the oil, not by a pump or external pressure. An oil safety valve for this setup is designed to be gravity-operated so that if the line develops a leak and the hydrostatic pressure behind the valve drops, the valve closes automatically. This stops any further oil from flowing down the line due to gravity and helps prevent spills. A pressure-operated valve wouldn’t have a meaningful source to sense in a gravity-fed system, a vacuum-operated valve relies on suction that isn’t the trigger here, and a hydraulic valve assumes a separate pressurized circuit. So a gravity-operated oil safety valve is the appropriate choice.