What type of valve is a Pressure Relief Valve?

A Pressure Relief Valve is classified as an automatic valve because it is designed to operate without the need for manual intervention. Its primary function is to automatically release excess pressure from a system to prevent over-pressurization, which can lead to equipment failure or hazardous situations. This valve activates at a pre-set pressure level, allowing it to respond independently to changing pressure conditions within the system.

In contrast, a manual control valve requires human operation to open or close it, while a pressure-regulating valve maintains a set pressure, and a back pressure regulator serves to maintain upstream pressure by allowing fluid to flow based on certain conditions. These distinctions clarify why the Pressure Relief Valve is best categorized as an automatic valve, as it continuously monitors the system pressure and reacts accordingly without manual input.