What is the function of a pressure relief valve in a steam boiler?

The function of a pressure relief valve in a steam boiler is to prevent excessive pressure buildup by releasing steam. This is crucial because if the pressure within the boiler exceeds safe operational limits, it can lead to dangerous conditions, including the risk of a boiler explosion. The pressure relief valve automatically opens when the pressure reaches a predetermined level, allowing steam to escape and thereby reducing the pressure inside the boiler to a safe range. This safety mechanism is vital for maintaining the integrity of the system and ensuring safe operation.

Other options focus on different aspects of boiler operation: regulating fuel supply pertains to the burner, controlling water temperature relates to temperature management in steam systems, and measuring steam flow rate involves monitoring the actual steam output. While all these functions are important in steam boiler operation, they do not directly relate to the primary safety role played by the pressure relief valve.