Intelligent research significance of electric valve
The actual valve position of the valve has only three positions: open, closed and middle position, the valve position is controlled by the output torque of the valve motor. At present, our country usually adopts the stroke switch to control the valve motor, torque switch to protect the working mode. However, the travel switch and the torque switch is usually installed in the electric actuator, the valve position signal can not be directly from the valve shaft, the valve position indicator is only an approximate value, causing the valve loose or not in place. Select the output torque is too small will cause the controlled valve opening and closing difficult, so easy to make electric and burned; if the output torque is too large, once the control of electric actuator failure is easy to cause local structural damage to the valve. Therefore, this control method can not directly control the valve opening and closing and adjustment, the control accuracy is relatively low.
On the other hand, in this mode of operation, the direct stroke stop valve and the gate of the long-term action of the gate to form micro grooves inside the wall, will cause the valve to close the formation of leakage. Leakage is one of the sources of industrial pollution, the leakage of the valve will cause consumption of the media outflow increased, rising costs, the economic efficiency of enterprises decreased. Flammable, explosive, toxic and harmful media leakage, it is prone to fire, explosion, poisoning and personal injuries and other accidents. Strong corrosive medium leakage, will speed up the corrosion rate of plant and equipment, the use of the service life is shortened. Therefore, the leakage of the existence of a serious threat to the safety of production, and even the production can not be carried out. Therefore, the valve leakage problem can not be ignored. All along, the solution to the valve leakage are starting from the valve. Design optimization of the valve structure, reasonable selection of valve materials manufacturing according to different process conditions, improve the level of quality control valve in the production process, and selection of valves according to the optimum conditions of various chemicals in the production process. Although these methods can effectively eliminate the leakage of the valve problem, but if we can start from the change in control valve, direct control valve, when the valve leakage problem, through the feedback control of the valve motor control valve position compensation, thus more effective control valve. At the same time, to change the valve position control mode, but also to meet the needs of automated production.
Three, the present situation of the research of intelligent electric valve
1 research status of intelligent electric valve. Electric valve and electric actuator by the two parts, but so far, the two parts of the production or by different manufacturers to produce. The lack of communication between the various manufacturers, but to improve the quality of their products and ignore the whole two part of the "complete" problem. In addition, although there are now a breakdown of various types of valves technical standards and electric actuator industry standards, but there is no complete set of electric valve technical standards or standards are not uniform. These make the electric valve "complete" problems, the lack of a corresponding basis. On the other hand, the structure of the electric valve, the structure of the valve is relatively simple, and the structure of the electric actuator is relatively complex. Therefore, people are more and more attention to the electric actuator, is committed to improving the level of intelligence. And ignore the level of the valve itself, the level of development of the intelligent level of the two is not balanced, complete set of intelligent level is not high.
2 research status of intelligent electric actuator. In recent years, with the rapid development of microelectronics, computer and communication network technology and mechatronics technology, electric valve actuator has obtained the fast development, some domestic and foreign manufacturers have launched a smart electric actuator. The field bus communication protocol. These intelligent valve electric actuator using microprocessor system, all control functions can be achieved through programming. At present, the international and domestic advanced intelligent valve electric actuator products are mainly:
2.2 MOE700/MME800 ONTRAC series intelligent electric actuator. The intelligent electric actuator is Sichuan Chongqing ten factory by the German Hamp company (now owned by ABB group) are introduced and launched. MOE700 series digital adjustable S2 control mode, MME800 is a continuous adjustment type S4 control mode, they use the turbine worm structure mechanical self-locking, three-phase motor drive and intelligent control, digital detection technology, its running speed and torque can be online or offline wide range setting, high degree of standardization. Is a powerful, easy to use and a small amount of maintenance, with different speed reducer output angular displacement (torque up to 40000Nm) and linear displacement (thrust up to 80KN), driving all kinds of body or baffle.
The above characteristics of several kinds of intelligent valve electric actuator is electromechanical integration structure gradually replace the modular structure, intelligent control technology is gradually replacing the pure electronic control technology, communication technology with function gradually replaced with communication technology, digital control is gradually replacing the traditional analog control method, using non-contact infrared remote debugging technology gradually replace the contact type manual debugging technology.
The characteristics of intelligent electric valve
The needs of the market and the development of electric valve makes the process of the intelligent electric valve is necessary, at the same time, electromechanical integration trend, and the rapid development of microelectronics and computer technology, provides the technical support for the development of intelligent electric valve. Nowadays, the intelligent valve mainly includes the following features:
1 electric valve digital communication. Intelligent electric valve actuator using power line carrier way connected to host computer, PC sends the addressable digital signal received by the electric actuator through the power line, electric actuator controller based on the received signal to the control of the electric actuator, electric valve work more flexible.
2 valve control process of the computer. Generally, the actuator in accordance with the control signal from the microprocessor control system to drive the valve, so as to adjust the opening of the valve to adjust the flow and pressure. If the servo amplifier with intelligent control is added in the electric actuator, the control function of the given value is added. The use of intelligent controller, can change the previous mechanical torque control switch action value adjustment need to open the sealed enclosure through the adjustment of the spring torque adjustment of the situation.
3 electric valve fault diagnosis and treatment of intelligent. Intelligent electric valve should have perfect function of fault self diagnosis. By loading additional sensors on the valve electric actuator, it can play a role in the fault diagnosis of the electric valve. When necessary, can also set up in various aspects such as detection circuit, intelligent electric valve can identify negative torque, when the control command and the implementation is inconsistent, the reverse phase sequence control contactor immediately, to achieve phase synchronization; intelligent electric valve can also detect three-phase current, detected phase stop valve motor.
4 integration of the whole structure. Electric valve in the process of intelligent, can not be separated from the valve and the integration of electric actuator design. Through the integration of the valve structure, the control circuit is arranged in a field instrument, the control system design, installation, operation and maintenance work is simplified, but also reduce the impact on the system for signal transmission in the leakage and the interference factors, reliability is improved.