Which valve type is primarily used to throttle flow in steam lines?

• A. Globe valve
• B. Gate valve
• C. Check valve
• D. Ball valve

Answer: (A)

Throttling flow in steam lines works best when you have a valve that can give you fine, gradual control over how much space is left for the steam to pass. A globe valve is designed for this purpose. The movable disc sits against a seat to create a variable orifice as it moves, and the flow path around the disc is relatively long. This combination lets you change the flow rate smoothly and predictably, giving you good control of steam volume and pressure.

Gate valves are built for opening and closing with minimal leakage when fully open or closed. When they’re only partly open, the flow can be erratic and difficult to regulate precisely, so they aren’t as good for throttling. Check valves prevent backflow, not regulate forward flow. Ball valves provide quick shutoff and are not ideal for fine throttling, since the flow control isn’t as smooth or linear as with a globe valve.

So, for precise control of steam flow, the globe valve is the best choice.