Which type of valve is commonly used to prevent backflow during water supply operations?

The check valve is specifically designed to allow fluid to flow in one direction while preventing any backflow. In the context of water supply operations, backflow can pose significant risks, including contamination of the water supply and disruption of water service. The check valve achieves this by utilizing a mechanism, often a flap or a ball, that closes off the flow path when there is a reversal of flow. This ensures that once water is pushed through the system, it cannot flow back towards its source, which is critical in maintaining system integrity and safety.

In contrast, while gate valves, ball valves, and globe valves all have their uses in controlling flow, they do not inherently prevent backflow. Gate valves are primarily used for starting and stopping the flow of water, while ball valves provide quick shut-off and globe valves are used for throttling flow control. None of these valves possess the automatic flow-restricting feature that is essential for preventing backflow, making the check valve the most suitable choice in this context.