What type of valve would you use to allow flow in one direction while preventing it in the opposite direction?

A check valve is specifically designed to allow fluid to flow in one direction while preventing backflow. This function is critical in various piping systems to maintain pressure and ensure that fluids do not reverse course, which could lead to system malfunctions or contamination.

The structure of a check valve typically includes a flap or disc that automatically opens when fluid flows in the intended direction and closes when the flow reverses. This self-acting mechanism provides a reliable way to control flow direction without requiring manual intervention, which is essential in many industrial and residential applications.

In contrast, gate valves are used to start or stop the flow rather than control flow direction; they do not prevent backflow. Ball valves can also stop or allow flow but do not inherently have a mechanism to prevent reverse flow. Globe valves are primarily designed for regulating flow rather than backflow prevention. Therefore, while the other valve types have specific uses in controlling flow, the check valve stands out for its unique role in preventing backflow while allowing forward flow.