What is the primary purpose of a pressure relief valve?

The primary purpose of a pressure relief valve is to act as a safety device that releases pressure from a system to prevent overpressure conditions. In various applications, such as boilers, pressure vessels, and piping systems, pressure can build up due to thermal expansion or mechanical failure. If this pressure exceeds the design limits of the system, it can lead to dangerous situations like equipment failure, explosions, or leaks.

The relief valve is designed to open at a predetermined pressure, allowing excess fluid (typically gas or steam) to escape safely into the atmosphere or a designated area, thus relieving the pressure and protecting the integrity of the system. This function is critical in maintaining the operational safety of industrial and commercial facilities that handle pressurized processes.

In contrast, other options provided do not fulfill the primary role of a pressure relief valve. For instance, increasing pressure in a system contradicts the safety function of a relief valve, as it aims to prevent dangerous pressure levels. Measuring temperature is not relevant to the valve's function, which focuses on pressure control. Lastly, regulating the flow of liquids in a pipeline pertains to different equipment, such as control valves or flow regulators, and does not involve the safety aspect of pressure management that a relief valve provides.