Comparing pneumatic, electric, and hydraulic actuators

Actuators(drives) are an essential component of automatic control systems. Their primary function is to receive control signals from the controller and adjust the controlled medium, accordingly, ensuring that the controlled variable is maintained within a desired value or range. Based on their energy source, actuators can be categorized into pneumatic, hydraulic, and electric types.

Pneumatic actuators use compressed air as their energy source. They are widely used in industries such as chemical manufacturing, paper production, and refining due to their simple structure, reliable operation, smooth action, large output force, ease of maintenance, fire and explosion resistance, and relatively low cost. Pneumatic actuators can be easily integrated with passive instruments, and even when using electric instruments or computer controls, they can still be utilized by converting the electrical signal to a standard pneumatic signal (20-100 kPa) via an electro-pneumatic converter or valve positioner.

Electric actuators, on the other hand, are convenient in terms of energy sourcing and offer fast signal transmission, but they are more complex and have poorer explosion-proof capabilities. Hydraulic actuators, which are rarely used in chemical or refining processes, are characterized by their ability to generate very high output forces.

Actuators(Drives) are primarily used in three main areas:

Power Plants:

Typical applications include fan damper control, burner adjustment rods, steam and gas valves, bypass dampers, and various other control valves and dampers in the thermal power industry, as well as control of large hydraulic valves and gas control valves in other power sectors.

Process Control:

Utilized in industries like chemicals, petrochemicals, molding, food, pharmaceuticals, and packaging, electric actuators ensure precise positioning and control of valves, tools, pipes, dampers, chutes, and platforms based on predefined logical commands or computer programs. They adjust system parameters such as temperature, pressure, flow, and others in real time to achieve intermittent, continuous, or cyclic process control.

Industrial Automation:

Broadly used in aerospace, defense, machinery, metallurgy, mining, transportation, construction materials, and more, to control and adjust various movement points or components within automated systems.

Comparing pneumatic, electric, and hydraulic actuators:

Pneumatic Actuators（Pneumatic Drives):

Predominantly used in industrial control due to their cost-effectiveness, simplicity, and ease of maintenance. They are ideal for explosive environments but may have slower response times and less control precision due to the compressibility of air.

Electric Actuators(Electric Drives):

Primarily used in power plants for high-pressure systems requiring smooth, stable operation. They offer high stability and consistent output force, but their complexity makes them more prone to faults and harder to maintain. They are slower in operation compared to pneumatic and hydraulic actuators.

Hydraulic Actuators(Hydraulic drives):

Preferred in scenarios requiring exceptional anti-deviation capabilities and high thrust, such as in power plants or petrochemical facilities. They offer fast response and high precision control but are expensive, large, and complex, requiring specialized engineering and maintenance.

Overall, each type of actuator has its strengths and weaknesses, making them suitable for different applications depending on the specific requirements of the control system