Passed the ISO9001 quality system certification and the establishment of industrial drying industry alliance standards under the guidance of the Chinese Standardization Research Institute.
- May 08, 2019 -
microwave heating compared with RF heating are as follows: (1) microwave power source (2) application (3) waveguide element and feed structure (4) sensing and control. The microwave power source of
generates microwave power is usually driven by magnetron, in which the hot cathode emits electrons and the electrons move in a circular direction under the action of a strong constant magnetic field. The resonant cavity inside the magnetron decelerates the electrons, so that the kinetic energy of the electrons can be transformed into the energy of the electromagnetic wave, accumulated in the resonant cavity, fed into the waveguide tube, and then fed into the application for use. Magnetron needs DC high voltage power supply, filament heating power supply and constant magnetic field coil power supply, and needs corresponding protection and control circuit to form the whole microwave power source. The output of microwave power can be controlled by the excitation current of DC high voltage or constant magnetic field. Microwave applicator is an expanded waveguide tube, which is used as the place where electromagnetic waves interact with matter. The design considerations are to meet the shape and processing requirements of the processed materials, which can be divided into traveling wave type and resonant type. The waveguide element is the connecting part between the microwave power source and the applicator, in order to solve the problem that not only the magnetron can get the best load working condition, but also the applicator can get the effective feeding effect. Considering from the point of view of microwave technology, the waveguide element is accomplished through a variety of waveguide elements and feeding structures. At the same time, the waveguide element provides the number of incident power and overflow reflection power. According to. Sensor configuration is to detect the extent of field and material action, whether it meets the processing needs, such as temperature sensing and humidity sensing. According to the real-time sensing data and the real-time working state of the microwave power source, the device can effectively control the output and transmission speed of the power source. It is necessary to divide microwave power application equipment into four parts. Generally speaking, application equipment is single-piece production or small-batch production, which must be designed according to specific use requirements. It is a process similar to "tailoring". Microwave power application equipment is divided into four parts. Microwave power source and waveguide components are microwave engineering design, sensing and control engineering design. These three parts have strong universality and are not changed by different application objects. Over the years, we have strengthened the standardization and serialization of these three parts, improved the reliability and stability of these components, provided a strong basis for the reliability of the whole machine, and shortened the development cycle of the whole machine. The design of microwave applicator has strong pertinence. It is a multi-disciplinary engineering design because of different processing requirements, different states, shapes and sizes of application objects. In recent years, we have adopted the design method of microwave applicator series. Different departments adopt specific general components to assemble, which reduces the newly designed components to very few, thus further shortening the equipment. The development cycle ensures the reliable quality of the equipment.
2. The present situation of microwave power application in China in the early 1970s, we paid attention to the development of microwave power application technology abroad. As early as at the end of 1972, the Ministry of Electronics Industry held a seminar on microwave tube technology at Nanjing 772 Power Plant (Sanle Electric Corporation). It focused on the possible development of microwave tube applications in new fields, such as industrial applications of microwave heating and drying, microwave therapy, microwave diagnosis and microwave plasma. The development of high power continuous wave magnetron is the precursor of the research work in new fields. In that year, 772 plant began to develop 915 MHz and 450 MHz continuous wave magnetrons. On the basis of the successful development of two bands of continuous wave magnetrons, the first 2450 MHz microwave physiotherapy instrument and 915 MHz microwave heating equipment were developed. The first microwave heating equipment was exhibited in Beijing in the spring of 1974. The phenomenon of rapid microwave heating attracted widespread attention from the industry. In November 1974, the Ministry of Electronic Industry held a symposium on the application of microwave energy technology in Nanjing 772 Plant. The application of microwave power abroad in industrial production, agricultural production and medical treatment was introduced, and the prospect of development in China was discussed. After more than 20 years of efforts, China has initially established the foundation of microwave power application in this field. The microwave power equipment developed by 772 Factory has been firmly established in food, wood and bamboo products processing, pharmaceutical, paper products, wine-making, rubber, chemical and other industrial production, improved production conditions, improved product quality, and developed a variety of microwave plasma equipment. Microwave high temperature equipment and microwave vacuum drying equipment have become an important means of scientific research in many disciplines.
As far as the national situation is concerned, the popularization of microwave power application technology in China has been a very arduous journey for more than 20 years. At present, preliminary achievements have been made and the foundation for further development has been laid. The main signs of this foundation are: (1) Microwave heating and drying, microwave food processing, microwave sterilization and insecticide have been widely used in various industries; (2) Household microwave ovens have formed regulations. The ability of mould production; (3) The clinical application of microwave medical instrument has achieved universal success; (4) At present, many frontier subjects in many fields, using microwave power as a powerful tool, have made many gratifying progress and expanded research positions in new fields, which has kept up with the pace of the world
3. Microwave power applications are moving towards high-tech fields from the perspective of research trends around the world. The application is in the period of developing to a new field, that is, the focus of research has shifted from traditional heating and drying, food processing to many high-tech fields, as a new tool for research work. The main fields are: microwave catalytic chemical reaction, microwave processing of new materials, and the research of various applications of microwave gas discharge. The experimental study of microwave chemistry covers almost all fields of chemistry and chemical industry. A large number of selected reports show that microwave electromagnetic field can accelerate chemical reaction and shorten the reaction time to one tenth to one thousandth of the original time, which brings an attractive prospect to chemical industry. Microwave high temperature technology can sinter fine ceramics, weld ceramics, and process and process materials, such as thermal setting of polymer materials, heat treatment of non-metallic materials. Microwave method is superior to conventional methods. Microwave gas discharge, i.e. low temperature plasma formed by microwave electromagnetic field, is one of the main aspects of microwave power applications. Microwave plasma chemical vapor deposition (MPCVD) and plasma etching are the main methods of microelectronics processing. The preparation of diamond films and optical fibers also adopts MPCVD method, the preparation of ultrafine powder and microwave plasma method, which have many advantages. In microwave plasma, the activity of many particles is stronger than that of radio frequency plasma, so it is more advantageous for chemical reaction and material treatment. In addition, strong illumination light source (such as sulfur lamp) and microwave odor generator, which are composed of microwave electrodeless discharge, are likely to be industrialized step by step. According to preliminary research, the research hotspots in the new field of microwave power in China can be listed as follows: (1) The research of microwave beneficiation (microwave-assisted pyrolysis) has achieved laboratory results in the conversion of sulfides from non-ferrous metals to oxides, of nickel carbonate to nickel oxide, of gold ore desulfurization and of nitrates from radioactive isotopes to oxides. (2) Microwave-assisted organic and inorganic chemical reactions have done a lot of laboratory work to improve the chemical reaction rate. (3) Study on microwave-assisted extraction technology. Microwave electric field can accelerate the dissolution rate and improve the solubility, which has achieved remarkable results in many laboratories. Microwave-assisted extraction
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