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

Relief valves in hydraulic systems serve a crucial purpose in preventing damage. They are designed to monitor and control the pressure within the hydraulic system. When the pressure exceeds a predetermined limit, the relief valve opens and allows hydraulic fluid to escape, effectively reducing the pressure in the system. This action safeguards various components of the aerial device, including hoses, pumps, and cylinders, from excessive pressure that could lead to failures or catastrophic damage. This protective function is essential in ensuring the safe operation of aerial devices, as it maintains the integrity of the equipment, thereby enhancing safety for both the operators and the structure being accessed.