Pneumatic, electric and hydraulic actuator between what are the advantages and disadvantages

Regulating valve actuator is used in pneumatic, electric, hydraulic, Electric hydraulic) The three, its use performance each have advantages and disadvantages, the points mentioned below. , pneumatic actuators: most of today's industrial control occasions the pneumatic actuators are used, because the use of gas source in power, by contrast, is economical and practical than electric and hydraulic, and simple structure, easy to master and maintain. By the maintenance point of view, pneumatic actuators than other types of actuators are easy to operate, and the calibration of the, also can easily achieve positive and negative at the scene about swaps. Its biggest advantage is safety, when using the locator, is ideal for flammable and explosive environment, and telecommunications, if it is not explosion-proof or intrinsically safe has the potential danger of fire caused by the flames. So, although now electric regulator application scope is more and more widely, but in the field of chemical industry, pneumatic control valve or occupy the absolute advantage. Pneumatic actuators main drawback is: slow response and poor control precision, poor ability to resist deviation, this is because of gas compressibility, especially the use of large pneumatic executing agency, the air filled cylinder and emptying time. But this should not be a problem, because many working condition does not require a high degree of control accuracy and extremely fast response and ability to resist deviation. , electric actuator, electric actuator is mainly used in power plant or nuclear power plants, because in the high pressure water system needs a smooth, stable and slow process. The main advantage of electric actuators is a high degree of stability and the user can be used of constant thrust, maximum actuators that generates the thrust can be as high as KGF, can achieve only so big thrust hydraulic actuators, but the cost is higher than the electric hydraulic actuators. Electric actuator deviates from the resistance is very good, the output of the thrust or torque is basically constant and can be very good to overcome the medium unbalanced force, to achieve accurate control of process parameters, so the control accuracy is higher than pneumatic actuators. If with servo amplifier, can easily achieve positive and negative role reversal, also can easily set off valve position signal status ( Keep/open/close) And failure, must remain in situ, which is less than pneumatic actuators, pneumatic actuators must use a set of integrated protection system to achieve the position. Electric actuator faults mainly include: structure is complex, are more likely to happen malfunction, and because of its complexity, the technical requirements of maintenance personnel on the spot is relatively high; Motor running to generate heat, if the regulation is too frequent, easily cause motor overheating, thermal protection, it will also increase the wear reduction gear; Another is running slowly, from the regulator output a signal, the response and the regulator movement to the corresponding position, need a long time, this is not as good as pneumatic, hydraulic actuator. , hydraulic actuators: when need anomalies deviate from the resistance and the formation of high thrust and fast speed, we tend to use hydraulic or electro-hydraulic actuator. Because the incompressibility of the liquid, the use of the advantages of hydraulic actuators is a better ability to resist from, this is very important for operating conditions, because when regulating elements close to the seat throttling condition is unstable, the more the pressure difference is big, the more powerful the situation. In addition, the hydraulic actuators to run smoothly, fast response, so can realize high precision control. Electric hydraulic executing agency is the motor, oil pump, electro-hydraulic servo valve is integrated into an organic whole, as long as connected to the power and control signals can get a job, and hydraulic actuators and cylinder, only higher pressure than cylinder ability, it is needed to outside of the hydraulic system, the need in the factory is equipped with hydraulic station and pipelines, in contrast, more convenient or electro-hydraulic actuator. Hydraulic executing agency is the main drawback of expensive, check-up hulking, particularly complex and require specialized engineering, so most of them are used in some special occasions such as power plants, petrochemical.