Which valve type is commonly opened or closed by a quarter-turn of its handle?

Which valve type is commonly opened or closed by a quarter-turn of its handle?

• A. Butterfly.
• B. Gate.
• C. Siamese.
• D. Post-indicating.

Answer: (A)

Opening or closing with a quarter-turn is a hallmark of a butterfly valve. It uses a circular disc inside the valve body that you rotate with a handle about 90 degrees. When the handle is aligned with the pipe, the disc is parallel to the flow, and the valve is open. A single 90-degree turn moves it to the perpendicular position, blocking flow and shutting the valve. This design allows quick, simple isolation, which is why it’s commonly used in firefighting lines. Other types, like gate valves, need many turns of a wheel to raise or lower a gate, so they’re not operated with a quick quarter-turn. The post-indicating valve and the Siamese connection aren’t typically quarter-turn valve types—the former mainly indicates position and the latter is a hose-connection arrangement rather than a valve type.

Opening or closing with a quarter-turn is a hallmark of a butterfly valve. It uses a circular disc inside the valve body that you rotate with a handle about 90 degrees. When the handle is aligned with the pipe, the disc is parallel to the flow, and the valve is open. A single 90-degree turn moves it to the perpendicular position, blocking flow and shutting the valve. This design allows quick, simple isolation, which is why it’s commonly used in firefighting lines. Other types, like gate valves, need many turns of a wheel to raise or lower a gate, so they’re not operated with a quick quarter-turn. The post-indicating valve and the Siamese connection aren’t typically quarter-turn valve types—the former mainly indicates position and the latter is a hose-connection arrangement rather than a valve type.