Which type of valve has a movable disk that rotates on a spindle to control water flow?

The butterfly valve is designed with a movable disk that rotates on a spindle to regulate the flow of water. This mechanism allows for efficient flow control, as the disk can be positioned in various angles to either restrict or allow water passage. This type of valve is particularly advantageous in applications where rapid opening and closing is necessary, thanks to its quick operating capability. The design minimizes energy loss and pressure drop due to its flat disk profile, making it ideal for large volume systems.

In contrast, the globe valve uses a spherical body and a disk that moves vertically against a seat, which makes it less efficient for quick shut-off or flow regulation compared to a butterfly valve. The gate valve operates by raising or lowering a gate to open or close the flow, which is typically slower and not as precise in flow control. The check valve's purpose is to allow flow in one direction and prevent backflow, and it does not have a rotating mechanism like the disk in a butterfly valve. Understanding these distinctions clarifies why the butterfly valve is uniquely suited for the description provided in the question.