What type of valve is commonly used as a shut-off in gas pipelines?

A ball valve is commonly used as a shut-off in gas pipelines primarily due to its design and functionality. The ball valve consists of a spherical disc, or ball, which has a hole through the center. When the ball is rotated so that the hole is aligned with the flow, the gas can pass through with minimal resistance. Conversely, when the ball is turned 90 degrees to the flow, it effectively blocks the gas, creating a tight seal and stopping the flow.

This type of valve is favored in gas applications for its ability to provide a reliable and durable shut-off solution, as well as its straightforward operation. Ball valves tend to offer low-pressure drop and a compact design, making them suitable for installations where space might be limited. Additionally, they require only a quarter turn to open or close, allowing for quick action in emergency situations.

In contrast, other valve types, such as the globe valve, which is better suited for throttling purposes, or the butterfly valve, which is typically used for regulating flow and handling larger volumes of fluids, do not offer the same level of efficacy for complete shut-off applications in gas pipelines. Check valves, on the other hand, allow flow in one direction and are used primarily to prevent backflow rather than