Actuator is an important aspect of the whole process control in pipeline system. The total system has three basic parts. Those parts are sensor, controller and actuator. Using actuators is to receive a control signal sent from the controller to modify the flow of the controlled media, so as to maintain the variable at the desired value or within a certain range. The action of the actuator is achieved by adjusting the output signal by the various implementing parts to achieve. Actuator consists of actuator and adjustment mechanism. Actuator control system is carried out as a tool to control the variables of changes in the system.

In the working process of entire process control, an actuator composes of two parties, actuator and adjustment mechanism. Adjustment mechanism changes the numbers of the production process directly through the implementation of components. As a result, it can make the entire production process to respond to the requirement. Another separate, the actuator receives control information from the controller and then it will be converted to output of the adjusting mechanism (such as angular displacement or linear displacement output).

According to energy input, actuators are divided into the form of pneumatic actuators, electric actuators and hydraulic actuators three categories. They have different features, and are adapted to different occasions. With the continuous development of various types of implementing mechanisms in recent years, science and technology are gradually moving towards intelligent roads, particularly professional and smart valve position supporting the use of pneumatic actuators.

Next it is going to look at mainly the pneumatic one and the electric one. Pneumatic actuator is a form of actuators which is utilized in the daily production. Pneumatic actuator and adjustment mechanisms are an attached body and there are different kinds of adjustment mechanisms, such as fork type, piston type and thin film type. It is a device, which acts according to pressure applied in it. Pressure builds up by compressed air or gas called the pneumatic actuators. The pressure applied by water or oil called for hydraulic actuators. The device actuators converts motion in linear or vertical rotary directions. The main part of actuator is cylinder, diaphragm and piston. 

The electric actuator converts electrical energy into torque. An electric motor mechanically is connected. They are found in processing plants of many kinds including refineries, power and wastewater treatment plants. They perform very important functions within the industrial manufacturing process. They are absorbing devices which cause another device to be powered up and off. Their sizes vary from a few inches long to a few meters. 

There is considerable room for expansion in the actuator industry at the present. The main factors of the expansion include the growing energy demand, sustained increase in global population and urbanization in developing countries, the process of industrialization after the financial crisis. This trend has been growing steadily for years. Currently, the world's major economies have already entered the economic recovery cycle. The actuator industry was showing a steady upward growth therewith.