Which of the following valves is best suited to regulate or 'throttle' flow?

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Throttle control relies on a valve whose flow rate changes smoothly as you adjust opening. The globe valve excels here because its movable disk seats against a fixed ring, creating a flow path that changes gradually as the disk lifts away from the seat. This yields a nearly linear relationship between how far the valve is opened and the flow rate, so small turns of the handwheel produce precise, predictable changes in flow. It also provides reliable throttling across a wide range and still offers solid shut-off when fully closed.

A check valve is designed to prevent backflow, not to regulate flow. A ball valve is optimized for quick on/off operation; its flow changes are more abrupt, making fine control difficult. A butterfly valve can throttle in larger pipes, but its flow characteristic is nonlinear, especially at small openings, which makes precise control less predictable and can complicate accurate regulation.

So, for regulating or throttling flow, the globe valve provides the best combination of controllability, predictability, and range of adjustment.