A Brief Introduction To Actuators

Actuator is an indispensable and important part of automatic control system. Its function is to accept the control signal sent by the controller and change the size of the controlled medium, thereby maintaining the controlled variable at the required value or within a certain range. Actuators can be divided into three categories according to their energy forms: pneumatic, hydraulic and electric. Pneumatic actuators use compressed air as an energy source, which is characterized by simple structure, reliable action, stable output, large output thrust, convenient maintenance, fire and explosion-proof, and low price, so it is widely used in chemical, paper, oil refining and other production processes. It can be conveniently used with passive meters. Even when using electric instruments or computer control, as long as the electric signal is converted into a standard air pressure signal of 20-100kPa through an electric-pneumatic converter or an electric-pneumatic valve positioner, a pneumatic actuator can still be used. Electric actuators have convenient energy access and rapid signal transmission, but have complex structures and poor explosion-proof performance. Hydraulic actuators are basically not used in chemical, oil refining and other production processes, and are characterized by a large output thrust.