Which type of valve is commonly used to start or stop flow in piping systems?

The ball valve is commonly used to start or stop flow in piping systems due to its design and functionality. These valves consist of a spherical disc, known as the ball, which has a hole drilled through the middle. When the valve is open, the hole is aligned with the flow direction of the piping, allowing fluid to pass through with minimal resistance. Closing the valve rotates the ball so that the hole is perpendicular to the flow direction, effectively stopping the flow.

Ball valves provide a quick and efficient method of flow control, often requiring only a quarter turn to fully open or close. This swift operation makes them ideal for applications where rapid shutoff and reliability are essential. Additionally, ball valves maintain a good sealing capability, which minimizes leakage when closed.

While other types of valves, such as gate valves and globe valves, can also be used for flow control, they are typically less efficient for quick operation. Check valves, on the other hand, are designed to prevent backflow rather than to start or stop flow, making them unsuitable for this specific function.