Which type of valve is primarily used for throttling?

The globe valve is primarily used for throttling because of its design, which allows for precise control of fluid flow. The internal structure of a globe valve includes a movable disk and a stationary ring seat, which together create a restriction in the flow path. This feature enables the operator to adjust the position of the disk and, consequently, the size of the opening through which the fluid passes. As a result, globe valves can effectively manage flow rates and provide a consistent level of control, making them ideal for applications where regulation of flow is necessary.

In contrast, a check valve is designed to allow flow in one direction and prevent backflow, which means it does not provide the capability for flow regulation or throttling. A relief valve, on the other hand, is intended to relieve excess pressure in a system, activating only under specific conditions rather than allowing continuous flow manipulation. Lastly, a ball valve is typically used for on-off service where the flow is either fully open or fully closed, and while it can restrict flow to some extent, it does not allow for the fine regulation that a globe valve does. Thus, the globe valve stands out as the preferred choice for throttling applications.