Which component functions as a barrier preventing backflow in steam systems?

The non-return valve is specifically designed to prevent backflow in steam systems, which is essential for maintaining proper system operation and safety. When steam or water flows in the intended direction, the non-return valve allows that flow through; however, if there is any attempt for the flow to reverse, the valve automatically closes, creating a barrier that stops the backflow. This function is crucial for preventing issues such as contamination of the supply line, loss of pressure in the system, and potential damage to components.

In contrast, the safety valve serves to release excess pressure to ensure that the system does not exceed safe operating limits, while the pressure regulator controls and maintains a specific pressure within the system but does not inherently block reverse flow. The boiler feed pump is responsible for supplying water to the boiler and does not play a role in preventing backflow. Thus, the non-return valve is the essential component that effectively addresses the need for backflow prevention in steam systems.