What is the main function of a pressure relief valve?

The main function of a pressure relief valve is to maintain safe pressure levels within a system. This device is essential for preventing overpressure situations that could lead to equipment failure or potentially dangerous conditions. When the pressure exceeds a predetermined level, the valve opens to release excess pressure, protecting the integrity of the system and ensuring safe operation.

Maintaining safe pressure levels is critical in refrigeration and other systems where pressure buildup can cause catastrophic failures. This ensures that the components do not operate above their designed limits, which helps in extending the lifespan of the equipment while also ensuring the safety of personnel and the environment.

In contrast, the other choices do not align with the primary function of a pressure relief valve. For example, regulating boiler feedwater is a different function, typically handled by feedwater control systems. Cooling the system pertains to heat exchange processes, and purifying steam involves water treatment methods, none of which are functions of a pressure relief valve. Thus, option B accurately reflects the essential role of a pressure relief valve in maintaining system safety.