Which of the following valves is classified as a rotary action valve?

A ball valve is classified as a rotary action valve because it operates by turning a hollow, spherical ball inside the valve body. When the ball's hole is aligned with the flow path, fluid can pass through; when the ball is rotated 90 degrees, flow is blocked. This design allows for quick opening and closing, making ball valves particularly efficient in applications where rapid shutoff is necessary.

Rotary action valves are characterized by their simple and effective way of controlling flow through rotational movement. In the case of the ball valve, the spherical shape offers minimal resistance to flow when open and a tight seal when closed. This capability makes it ideal for a variety of applications in different industries.

Understanding the operation of rotary valves is essential for instrument technicians, as they frequently encounter these devices in process control systems and need to be familiar with their function, applications, and maintenance.