Valve actuators enable valves to be adjusted from a remote location.
They are classified according to their range of movement, or travel:
- Multi-turn actuators – used with multi-turn applications such as gate valves.
- Part-turn actuators – used with part-turn applications such as butterfly and ball valves.
When an actuator receives a signal from the site control system it opens or closes the associated valve accordingly. Nowadays, actuators are usually driven by electric motors, although some systems are still based on pneumatic actuation.