What term describes a device that allows the bypass of fluids to limit pressure in a system?

A relief valve is designed specifically to manage and limit pressure within a fluid system. When pressure exceeds a predetermined level, the valve opens to allow excess fluid to escape, thereby reducing pressure and protecting the system from potential damage. This functionality is crucial in various applications, such as hydraulic systems, to prevent catastrophic failures due to overpressure.

In contrast, a pressure gauge measures pressure but does not control it; a flowmeter quantifies fluid flow but does not influence pressure; and a check valve allows fluid to flow in one direction and prevents backflow but does not actively manage pressure levels. Thus, the relief valve's purpose of relieving excess pressure makes it the correct term in this context.