Which valve is typically used as a stop/start valve with a circular body almost parallel to flow?

• A. Globe valve
• B. Check valve
• C. Butterfly valve
• D. Plug valve

Answer: (A)

Stop/start performance relies on a valve that can be opened and closed cleanly with a positive seal and smooth, linear motion of the sealing element in line with the flow. The globe valve fits this need. Its body is essentially circular and sits in the pipe axis, while the disk (the sealing element) moves in a straight line toward and away from the seats. That straight, predictable motion gives a reliable on/off shut-off and good control when slight throttling is used. In other valve types, the opening/closing action or flow path isn’t as well suited to precise start/stop with a robust seal: check valves aren’t operated manually for stop/start, butterfly valves rely on a rotating disk and are less ideal for tight throttling control, and plug valves use a rotating plug in a different flow path.