What Is the Difference between Pneumatic Actuators and Electric Actuators?

Pneumatic actuators, also known as pneumatic devices, are actuators that use air pressure to drive open and close or adjust valves, but they are generally called pneumatic heads. Air powered actuators are sometimes equipped with certain auxiliary devices. Commonly used are valve positioners and handwheel mechanisms.

 

An electric actuator is a driving device that can provide linear or rotary motion. It uses a certain driving energy and works under a certain control signal. The actuator uses liquid, gas, electricity or other energy and converts it into a driving function through a motor, cylinder or other device. The basic types of electric motor actuators have three drive modes: Part-Turn, Multi-Turn and Linear.

 

Performance Comparison between the Two

 

In terms of technical performance, the advantages of pneumatic air actuator mainly include the following four aspects.

 

The load is large and can be adapted to applications with high torque output.

 

It moves quickly and reacts quickly.

 

Pneumatic actuators have good working environment adaptability, especially in harsh working environments such as flammable, explosive, dusty, strong magnetism, radiation and vibration. It is superior to hydraulic, electronic and electrical control.

 

The motor is easily damaged when the stroke is blocked or the valve stem is tied.

 

The advantages of electric actuators are as follows.

 

It has a compact structure and small size. Compared with pneumatic actuators, motorised actuators have a relatively simple structure. A basic electronic system includes an actuator, a three-position DPDT switch, a fuse and some wires.

 

The driving source of the electric actuator is very flexible, and the general vehicle-mounted power supply can meet the needs, while the pneumatic actuator requires an air source and a compression drive device.

 

Electric actuators have no risk of "leakage" and are highly reliable, while the compressibility of air makes the stability of the pneumatic actuator control system slightly worse.

 

No need to install and maintain various pneumatic pipelines.

 

The load can be maintained without power, while pneumatic actuators require continuous pressure supply.

 

Since no additional pressure device is required, the electric actuator is quieter. Usually, if the pneumatic actuator is under heavy load, a silencer should be installed.

 

In pneumatic devices, it is usually necessary to convert electrical signals into pneumatic signals and then into electrical signals. The transmission speed is slow, and it is not suitable for complex circuits with too many components.

 

Electric actuators are superior in control accuracy.

 

In fact, pneumatic systems and electric systems are not mutually exclusive. Pneumatic linear actuator can simply realize rapid linear circulation movement, simple structure and convenient maintenance. At the same time, it can be used in various harsh working environments, such as explosion-proof requirements, dusty or humid working conditions. But in situations where the force increases rapidly and precise positioning is required, an electric drive with a servo motor has advantages.

 

For applications requiring precise, synchronized operation, adjustable and prescribed positioning programming, electro pneumatic actuator is the best choice. An electric drive system composed of a servo or stepping motor with a closed-loop positioning controller can supplement the deficiencies of the pneumatic system. Various systems in modern control are becoming more and more complex and more sophisticated, and not a certain drive control technology can satisfy the multiple control functions of the system.

 

Intelligent electric actuators are mainly used in applications requiring precise control. The requirements for flexibility in automation equipment are constantly improving. The same equipment is often required to meet the processing needs of workpieces of different sizes. The actuator needs to be controlled by multi-point positioning, and the operating speed and torque of the actuator must be accurately controlled or synchronized. These can't be achieved using traditional pneumatic control, and electric actuators can easily achieve such control.

 

It can be seen that pneumatic actuators are more suitable for simple motion control, while electric actuators are mostly used for precise motion control.