What is the primary function of a relief valve in a hydraulic system?

What is the primary function of a relief valve in a hydraulic system?

• A. To precisely meter flow to an actuator
• B. To start fluid flow when system pressure reaches a threshold
• C. To filter particulates from the hydraulic fluid
• D. To limit maximum system pressure by venting excess fluid

Answer: (D)

Relief valves are safety devices that keep hydraulic pressure from exceeding safe levels. Their main job is to sense the system pressure and open when that pressure goes past the valve’s set point, routing fluid back to the reservoir (or to a lower-pressure path) to drop the pressure in the circuit. This protects pumps, hoses, seals, and actuators from overpressure and potential damage. They don’t meter flow to an actuator—that’s done by flow-control or metering valves—nor do they start fluid flow at a threshold, which would require a pressure-activated switch. They also don’t filter particulates; filtration is handled by separate filters.

Relief valves are safety devices that keep hydraulic pressure from exceeding safe levels. Their main job is to sense the system pressure and open when that pressure goes past the valve’s set point, routing fluid back to the reservoir (or to a lower-pressure path) to drop the pressure in the circuit. This protects pumps, hoses, seals, and actuators from overpressure and potential damage. They don’t meter flow to an actuator—that’s done by flow-control or metering valves—nor do they start fluid flow at a threshold, which would require a pressure-activated switch. They also don’t filter particulates; filtration is handled by separate filters.