A ball valve actuator is a mechanical device that is used to remotely or automatically open and close ball valves. These actuators are part of a family of valve actuators known as quarter-turn actuators. They are used specifically to open ball-and-gate valves that require only a quarter of a full revolution to open. Power sources for ball valve actuators include electric motors and pressurized air or oil. Electric actuators generally are used on smaller valves such as those used on irrigation lines, and the more powerful pneumatic and hydraulic types are used for larger industrial valves.
Ball valves, along with other quarter-turn types, such as gate and butterfly valves, are among the most common fluid flow control mechanisms used in applications ranging from domestic irrigation and potable water supplies to large valves in the heavy manufacturing, oil and gas industries. They consist of a chamber within which a close-fitting ball or flat, round plate rotates. In the case of a ball valve, the ball is hollow, which allows fluid to pass through it when it is orientated with the hollow section parallel to the fluid flow. When turned at right angles to the flow, the fluid cannot pass, and the valve is effectively closed. To achieve this action, a short, 45-degree turn is required, which gives the valves their quarter-turn name.
The quarter-turn identifier also is used to describe the family of actuators to which the ball valve actuator belongs. These devices allow the valves to be remotely opened or closed by an operator or as part of an automated system. They are specifically designed to produce only the short-throw, 45-degree range of motion that is required to fully cycle ball-and-gate valves. This limited range of motion makes the ball valve actuator especially suitable for pneumatic and hydraulic power sources, which are more suited to short-stroke applications. Electric actuators also are used, though, particularly on smaller valves that require less torque to open and close.
A wide range of ball valve actuator sizes are used in domestic, agricultural and industrial applications. The smaller types used in home irrigation and drinking water supplies or agricultural irrigation feature valves that range from about 0.5-2.0 inches (1.27-5.08 cm) in diameter. Those used in heavy manufacturing installations and the gas and petroleum industries can drive valves that have fluid paths that are more than 12 inches (more than 30.5 cm) in diameter. These larger ball valve actuator examples typically are hydraulically driven because of the high torque capabilities that are inherent in pressurized oil systems.