A valve actuator is the device to control the position of a valve. In order to have precise timing and flow control, integrate the whole system for automation purpose, reduce labor, and/or for safety reason, a valve actuator are often employed to accompany a valve in tubing/piping systems. For example, wastewater treatment plants, power plants and petroleum refineries all have intensive piping/valves/actuators systems.
An actuator may be driven by pneumatic, hydraulic, or electric power. The movement of an actuator can be calssified into Multi-turn, Part-turn, and Linear. An actuator can be in charge of Open-close, Positioning, or Modulating duty. An actuator may serves in some conditions that are not suitable for human labors, such as Enclosure protection, Ambient temperatures, and Explosion protection. Finally, the functions of an actustor can be simply Automatic switching off in the end positions, for Safety and protection functions, for precise Process control functions, or for Diagnosis purpose.
