What safety feature is commonly included in feedwater systems to prevent overpressure?

In feedwater systems, a pressure relief valve is a critical safety feature designed to prevent overpressure situations. This valve automatically opens when the pressure within the system exceeds a predetermined limit, allowing excess steam or water to escape. This prevents potential damage to the system components, such as pipes, pumps, and boilers, which could occur if pressure builds up excessively.

The pressure relief valve is designed to operate without human intervention, thereby ensuring a swift response to unsafe pressure levels. Once the pressure drops back down to a safe range, the valve closes, allowing the system to resume normal operation. This automatic operation makes it an essential component in maintaining safety and operational integrity in feedwater systems.

While the other options provide important functions in fluid systems, they do not specifically serve the purpose of managing pressure spikes in the way that a pressure relief valve does. Isolation valves control flow, check valves prevent backflow, and flow restrictors limit the volume of flow, but none of these directly relieve pressure when it exceeds safe levels.