Flow reversal in a piping system is prevented by which category of valve?

Flow reversal in a piping system is effectively prevented by a check valve. This type of valve is specifically designed to allow fluid to flow in one direction only, thereby preventing backflow. Check valves operate automatically; when the fluid pushes against the valve in the intended direction, it opens and permits flow. However, if the flow tries to reverse, the valve closes and blocks the pathway, ensuring that contaminants or undesired substances do not enter the system.

In contrast, other types of valves, like ball valves, gate valves, and globe valves, are primarily used for regulating or stopping flow but do not inherently prevent backflow when not actively operated. These valves require manual intervention to close or open, which means they are not suitable for situations where automatic prevention of flow reversal is necessary. This fundamental design characteristic of check valves is crucial in various plumbing and fluid systems to maintain system integrity and protect against potential damage or contamination.