Describe the purpose of a pressure relief valve in hydraulic systems.

The purpose of a pressure relief valve in hydraulic systems is to prevent overpressure damage. This valve serves as a critical safety device within hydraulic circuits, ensuring that the pressure does not exceed a predetermined level. When the system pressure rises above this limit, the pressure relief valve opens, allowing fluid to escape back to the reservoir or divert to another section of the system.

This function protects various components of the hydraulic system, such as pumps, hoses, and cylinders, from potential damage that could occur due to excessive pressure. By maintaining the pressure within safe operating limits, the pressure relief valve contributes to the longevity and reliability of the hydraulic system.

Considering other options provided, increasing system pressure is not a role of the pressure relief valve, as its function is to relieve pressure, not augment it. Regulating fluid flow is also not the purpose of this valve; that function is typically associated with flow control valves. Lastly, assisting with fluid mixing is unrelated to the function of a pressure relief valve, which focuses solely on managing pressure within the hydraulic system.