Advantages and Disadvantages of Electric Valves vs. Pneumatic Valves

Electric Valve
The  electric actuator  for valves is primarily used in power plants or nuclear power plants, as high-pressure water systems require a smooth, stable, and slow process. The main advantages of electric actuators are their high stability and the constant thrust they provide, with the thrust generated by the actuator reaching up to 225,000 kgf. Only Hydraulic Actuators can achieve such high thrust, but their cost is significantly higher than that of electric actuators.  Electric actuators have excellent resistance to deviation, ensuring that the output thrust or torque remains largely constant. This allows them to effectively counteract unbalanced forces in the medium, enabling precise control of process parameters. As a result, their control accuracy surpasses that of pneumatic actuators.  When paired with a servo amplifier, electric actuators can easily switch between direct and reverse actions and effortlessly set the valve position state (hold/open/closed) in case of signal loss. In the event of a malfunction, they will always remain in their original position, a capability pneumatic actuators cannot achieve without relying on a combined protection system to maintain position.
The main disadvantages of Electric Actuators are:
The structure is relatively complex, making it more prone to malfunctions. Due to its complexity, the technical requirements for on-site maintenance personnel are relatively higher. Motor operation generates heat, and excessive frequent adjustments can easily lead to motor overheating, triggering thermal protection, while also increasing wear on the reduction gears. Additionally, the operation is relatively slow—there is a significant delay between the regulator sending a signal and the regulating valve responding and moving to the corresponding position, which is a drawback compared to pneumatic or Hydraulic Actuators.
pneumatic valve
The actuator and regulating mechanism of the pneumatic valve actuator form a unified whole, with the actuator divided into two types: diaphragm and piston. The piston type offers a longer stroke and is suitable for applications requiring higher thrust, while the diaphragm type has a shorter stroke and can only directly drive the valve stem. Due to its simple structure, high output thrust, and stable, reliable operation, the Pneumatic Actuator is widely used in production processes with high requirements, such as power plants, chemical industries, and oil refining.
The main advantages of  pneumatic actuators :
Accept continuous pneumatic signals and output linear displacement (after the electro/pneumatic conversion device, it can also accept continuous electrical signals). With a mounted arm, it can output angular displacement.
It has both positive and negative effects.
The movement speed is high, but it slows down when the load increases.
The output force is related to the operating pressure.
High reliability, but the valve cannot maintain position when the air supply is interrupted (can be maintained with a position maintenance valve).
It is inconvenient to achieve segmented control and program control.
Easy to inspect and maintain, with good adaptability to the environment.
The output power is relatively high.
With explosion-proof function.