It may take 30 min or more to fully open or close this type of large valve

• A. Globe valve
• B. Horizontal gate valve
• C. Butterfly valve
• D. Check valve

Answer: (B)

The main idea here is why some large valves take a long time to move from fully closed to fully open. A gate valve is designed to isolate a line by lifting a gate (or wedge) out of the seats. When the valve is large, the gate is heavy and travels a long distance. In a horizontal gate valve, that travel must be accomplished through the threaded stem and operating gear, so there’s substantial friction and mechanical work to overcome. With large diameters and manual or slow actuators, fully opening or fully closing can require a lot of time—sometimes 30 minutes or more.

Butterfly valves open with a quick quarter-turn, so they’re not slow. Check valves operate automatically based on flow direction, so they don’t require manual operation. Globe valves throttle and do need more turns than a butterfly but usually don’t have the same long travel as a large gate valve, especially when considering ease of full travel in large sizes.

So, the valve type that best explains a very long time to fully open or close, particularly in large sizes, is the horizontal gate valve.