Which group of valve types share a common 90-degree operational action?

• A. Plug, ball, and butterfly valves
• B. Gate and globe valves
• C. Check and relief valves
• D. Needle and globe valves

Answer: (A)

The main idea is quarter-turn operation: many valves open or close with roughly a 90-degree rotation, moving from fully open to fully closed with a single turn. Plug valves, ball valves, and butterfly valves all use a rotatable element (a plug, a ball, or a disc) that aligns with or blocks the flow path as you turn it 90 degrees. When the element is aligned with the flow, the path is open; rotate it 90 degrees, and the path is blocked, giving a fast, straightforward on/off shutoff.

Other valve types use different motions. Gate and globe valves rely on linear movement of a gate or disk along the stem and typically require multiple turns or more travel to open or close. Check valves operate automatically with flow direction and don’t use a manual 90-degree rotation for opening; relief valves respond to pressure and open when set pressure is exceeded, not by turning a handle. Needle valves use fine, linear screw-action to adjust flow, not a 90-degree turn.

So the group sharing that 90-degree action is plug, ball, and butterfly valves.