Development status of electric actuators in China
The electric actuator is a very important field driving device in the industrial process control system. It is easy to use and easy to install and debug. It is widely used in the power, metallurgy, petroleum, chemical and other industrial sectors. The electric actuator consists of two parts: the electric actuator and the regulating valve. The control accuracy is mainly determined by the control performance of the electric actuator. It can convert the control signal of the system into the angular displacement and linear displacement of the output shaft, and control the position of the shut-off parts such as the valve. Or other adjustment mechanism to make the controlled medium work according to the system requirements.
The development of electric actuators in China started late, starting from the imitation of Soviet actuators with contacts. In the late 1960s and early 1970s, DDZ-II and DDZ-III products were gradually developed.
Since the 1980s, with the development of power electronics technology, electric actuators have developed rapidly. Two types of products, such as non-contact DKJ-type angular stroke and DKZ-type linear actuator, have entered the market. DKJ and DKZ are the earliest and unique in China. The electric actuator produced by this product is used by the earliest state-owned large enterprises with the advantages of simple structure, economy and practicality.
With the development of modern industrial computer management, the overall comprehensive technical level of China's instrumentation industry has generally increased. Microelectronics technology and computer technology are widely used in instrumentation products, and most products have been intelligent. Today, the DKJ and DKZ series have two substantial improvements compared to before:
(1) Producing improved products such as intelligent electronic type, outdoor type, and explosion-proof type directly controlled by computer;
(2) The circuit control part is potted in a small plastic box, that is, the module, forming a plug-and-play type that is easy to maintain. Therefore, the reliability, accuracy, load capacity, signal quality coefficient and other performances of the common DKJ type and DKZ type have been greatly improved, and the requirements for environmental conditions have been reduced a lot;
The intelligent electric actuator realizes intelligent control, high protection level, high control precision, light weight and good stability. For example, DZW series electric actuators produced by Yongjia Shenzhou Power Equipment Co., Ltd. have these characteristics, the basic error of position control = ± 1%, repeatability error: (set stroke time ≥ 25s) ≤ 1%. Integrated structure; transmission system adopts screw nut type, stable transmission, strong carrying capacity and high transmission precision; self-diagnosis, self-adjustment and PID adjustment.
At present, DZW and DKZ are widely used in China. Some enterprises use DKJ and DKZ to replace them. However, in the experimental and production control with high control requirements, they mainly rely on foreign smart products with higher prices. Such as German SIPOS, AUMA, EMG, British ROTORK, French BERNARD, the United States LIMITORQUE and other electric actuators. As various process control requirements continue to increase, electric actuators must improve control performance to truly improve the level of automatic control.