【 Weak current College 】 exceeds three implementing agencies performance analysis---Power By 【 China power house network 】

Control valve with actuator are pneumatic, electric, hydraulic (electro-valve) of these three, the use of performance have advantages and disadvantages, as described below. 1, pneumatic actuators: nowadays most of the IPC where the actuator is pneumatic actuators, because air powered, by comparison, the ratio of electric and hydraulic to affordable and simple structure, easy to learn and maintain. By maintenance standpoint, pneumatic actuators than other types of actuators is easy to operate and, in the scene can easily achieve the pros and cons of Exchange. Its biggest advantage is security, when you use the Locator for flammable and explosive environment is ideal, and the telecommunications numbers if not intrinsically safe explosion-proof or the potential for brand impact and cause a fire hazard. Therefore, although now electric regulating valve application range has become an increasingly widespread, but in the chemical field, pneumatic control valve or in occupies an absolute advantage. Pneumatic actuator's major disadvantage is: slow response, control accuracy is poor, poor resistance to deviate from the capacity, this is because the gas compression, particularly the use of pneumatic actuators, air filled cylinder and emptying takes time. But that shouldn't be a problem because many of the condition does not require a high degree of control precision and very fast response and the ability of deviation. 2, electric actuators: electric actuators are mainly used in power plants or nuclear power plant, because in the high pressure water systems require a smooth, steady and slow process. Electric actuator's main advantage is the high degree of stability and the user can apply constant thrust with a maximum thrust of the actuator can be as high as 225000kgf, can achieve so much thrust of only valve actuator, the valve actuator cost to much higher than electric. Electric actuator of deviation is very good, output thrust or torque is essentially constant, you can very well overcome the media's unbalanced force, reached on the precise control of process parameters, so the control accuracy ratio of pneumatic actuators. If equipped with servo amplifier, you can easily achieve the pros and cons of Exchange, you can easily set off the signal valve position status (keep/full on/full off), and failure, must remain in place, this is the pneumatic actuator, pneumatic actuator must resort to a combination of protection system for insurance. The disadvantage of electric actuators are: structure more complex, more prone to failure, and because of its complexity, the to field maintenance personnel for technical requirements relative to higher; motor run to produce heat, if regulation is too frequently easily lead to motor overheating, produce thermal protection, but also will increase wear of reduction gear; the other is running slow, a signal output from the regulator, to control valve response campaign to the appropriate location, take a long time, this is it is pneumatic, hydraulic actuators. 3, hydraulic actuators: when you need the ability to resist deviates from the exception and the high thrust and fast speed of formation, we often use hydraulic or electro-hydraulic actuators. Because the liquid of incompressibility, using hydraulic actuator advantage is a superior resistance to deviate from the ability to adjust the working conditions are very important, because when the regulatory element close when the throttle valve seat is unstable working conditions, the more pressure, the more the case. In addition, hydraulic actuator runs very smooth, fast response, it can realize high-precision control. Electro-hydraulic actuators is to motor, pump, electro-hydraulic Servo valves integrated in one, as long as access to the power supply and control signals, and valve actuators and cylinder are similar, but higher than cylinder withstands the pressure of work, it requires an external hydraulic system, factory need equipped with hydraulic station and pipeline, by contrast, or electro-hydraulic actuators and more convenient. Valve actuator's major disadvantage is the cost of expensive, clumsy, especially physical examination of a large complex and the need for specialized projects, most of which are used in some, such as power plants, petrochemical, and other special occasions. Editorial: Shin Bo Hun