What is the primary purpose of relief valves in hydraulic systems for aerial devices?

The primary purpose of relief valves in hydraulic systems for aerial devices is to prevent damage. Relief valves are critical safety devices that help maintain the hydraulic system's pressure within safe limits. When the pressure exceeds a pre-set level, the relief valve opens to allow excess fluid to escape, thereby preventing potential system failure or components from being subjected to pressures that could cause mechanical damage.

This safety function is essential, as excessive pressure can lead to catastrophic failures such as hose ruptures, seal leaks, or even structural damage to the aerial device itself. By managing and controlling the hydraulic pressure through the relief valve, the longevity and reliability of the hydraulic system are significantly enhanced, ensuring safe operation in the field.