The merits and demerits of the electric and pneumatic valve
Electric valve: the valve 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 225000 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. Explosion-proof electric wire stainless steel ball valve flange ball valve pneumatic explosion-proof electric gate GT GT pneumatic valve: the valve pneumatic actuators actuators and regulating mechanism is a unified whole, the executing agency with diaphragm and piston type two kinds. Piston stroke length, suitable for a greater thrust required; The diaphragm stroke is small, can only be direct drive valve stem. Due to the actuator has a simple structure, export thrust large, action is stable and reliable, and safe explosion-proof, etc, in power plant, chemical industry, oil refining, such as the safety requirements of high production process has a wide range of applications. The main advantage of the pneumatic actuators: 1, accept continuous gas signal, the output linear displacement ( After add electricity/gas conversion device, also can accept the continuous electrical signal) , some with rocker arm, but the output angular displacement. 2, have a positive, the reaction function. 3, movement speed, but slower speed when the load increases. 4, output force related to the operating pressure. 5, high reliability, but after air break valve cannot keep ( After the position control valve can keep) 。 6, inconvenience to implement piecewise control and program control. 7, maintenance is simple, good adaptability to environment. 8, the output power is larger. 9, with explosion-proof function.