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Advantages and disadvantages of electric and pneumatic valves

Electric valve
Valve actuators are mainly used in power plants or nuclear power plants because of the need for a smooth, stable, and slow process in high pressure water systems. The main advantage of the electric actuator is its high stability and constant thrust that can be applied by the user. The maximum thrust generated by the actuator is up to 225,000kgf. Only the hydraulic actuator can achieve such high thrust, but the hydraulic actuator is more expensive than the electric actuator. Much higher. The anti-deviation ability of the electric actuator is very good, the output thrust or torque is basically constant, it can overcome the imbalance force of the medium well, and achieve accurate control of the process parameters, so the control accuracy is better than the pneumatic actuator. high. If equipped with a servo amplifier, it is easy to realize the exchange of positive and negative effects, and it is also easy to set the status of the valve position of the off signal (maintain/full open/full close), and when it fails, it must stay in position. This is Pneumatic actuators cannot do this and pneumatic actuators must be secured by means of a combined protection system.
The disadvantages of electric actuators are:
The structure is more complex and more prone to failure, and due to its complexity, the technical requirements for on-site maintenance personnel are relatively higher; the motor operation generates heat, if the adjustment is too frequent, it will easily cause the motor to overheat and generate thermal protection. Will also increase the wear on the reduction gear; the other is the slower running, output a signal from the regulator, to adjust the valve to respond to move to that corresponding position, take a longer time, which is not as good as pneumatic, hydraulic execution Place.
Pneumatic valves
The actuator and adjustment mechanism of the valve pneumatic actuator is a unified whole, and the actuator is a film type and a piston type. The piston stroke is long and is suitable for applications where there is a need for high thrust; while the film-type stroke is small and can only directly actuate the valve stem. Because the pneumatic actuator has the advantages of simple structure, large output thrust, stable and reliable operation, safety and explosion proof, etc., it is widely used in power plants, chemical industry, oil refining and other production processes with high safety requirements.
The main advantages of pneumatic actuators:
Receiving continuous air signal, output linear displacement (can also receive continuous electric signal after power-on/gas conversion device), and some can output angular displacement when matched with rocker arm.
There are positive and negative effects.
The speed of movement is large, but the speed becomes slower as the load increases.
The output force is related to the operating pressure.
High reliability, but the valve cannot be maintained after the air supply is interrupted (can be maintained after the valve is installed).
Inconvenient to achieve segmented control and program control.
Maintenance is simple and the adaptability to the environment is good.
Larger output power.
With explosion-proof function.

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