1. The Summarize of Nonwoven Drying Oven Machine
The microwave mode inside the nonwoven drying oven machine is different from the traditional drying method, and its heat conduction direction is the same as the moisture diffusion direction. Compared with the traditional drying mode, it has the advantages of large drying rate, energy saving, high production efficiency, uniform drying, clean production, easy to realize automatic control and improve product quality, etc. Therefore, it is getting more and more attention in various fields of drying. As early as the 1960s, foreign countries have conducted a lot of research on the application and theory of microwave drying technology, and in recent decades has been further developed.
Microwave is a very short wavelength of electromagnetic waves, wavelength between 1mm to 1m, and its corresponding frequency between 300GHz and 300MHz. In order to prevent microwave interference to radio communications, broadcasting and radar, international regulations for microwave heating and microwave drying frequency have four sections, respectively: L section, the frequency of 890 ~ 940MHz, the centre wavelength of 330mm; S section, the frequency of 2400 ~ 2500MHz, the centre wavelength of 122mm; C section, the frequency of 5725 ~ 5875MHz, the centre wavelength of Only L-band and S-band are used in home microwave ovens.
The core of microwave drying equipment is the microwave generator, the current microwave drying frequency is mainly 2450 MHz, mostly used in chemical, food, agricultural and sideline products, wood, building materials, paper products and other industries, can also be used for food, agricultural and sideline products, such as the sterilization.
3. Drying Processes
In the traditional drying process, in order to improve the drying speed, the need to raise the external temperature, increase the temperature gradient, but then easy to produce the material outside the scorched inside the phenomenon of raw. But the use of microwave heating, regardless of the shape of the material, the heat can be uniform penetration and can produce the effect of expansion, conducive to crushing.
Under the action of the microwave, the drying rate of the material tends to be consistent, uniform heating. Moreover, microwave drying technology does not affect the colour, fragrance, taste and tissue structure of the dried materials, the active ingredients are not easy to be decomposed and destroyed. Relevant research institutions are proceeding to use microwave drying instead of traditional drying ovens to solve the traditional drying method to dry Sichuan herbal medicine when prone to uneven drying and other problems.
Microwave equipment supporting facilities less occupy less land, easy to operate, continuous operation, easy to automatic production and enterprise management (can be controlled by PLC programming, adjustable temperature).
4. Thermal Efficiency
Microwave non-woven drying process has a high energy utilization rate, which is because the heat of microwave is generated directly inside the wet material, with less heat loss, high thermal efficiency and no environmental and noise pollution, which can greatly improve the working environment.
The drying process involves almost all sectors of the national economy, widely used in production and life. The purpose of drying is to remove the moisture or solvent in certain raw materials, semi-finished products and finished products, so as to facilitate processing, use, transportation and storage. The general drying methods are mechanical method, chemical method and heating (freezing) method. These methods either have huge equipment and high drying cost, or slow drying speed and small processing capacity. With the development of science and technology, such as biological products, new materials (multi-phase composite materials, nanomaterials, intelligent materials and biomedical materials, etc.), advanced ceramics, new advanced food and new drug products and other new products, the traditional drying technology and dryer may not always adapt. Microwave drying technology and microwave dryer has been widely used in the light industry, chemical materials industry, food and agricultural products processing industry and other industries and has shown significant superiority. Microwave drying is undoubtedly a new technology to meet the requirements of new products
Compared with foreign countries, China started late in the application of microwave drying technology research, although many achievements, but the application of microwave drying technology research field is narrow, mostly in the experimental stage or small-scale production stage, composite microwave drying technology research needs to be expanded, microwave drying of instantaneous mass transfer heat transfer theory research is not enough, and microwave drying technology supporting the development of equipment and instruments still need to be strengthened. In addition, although theoretical research on the application of microwave drying in the drying of natural rubber has made great progress, its scale, continuous and automated there are still many problems to be solved, microwave drying of rubber molecular structure, non-rubber components and the impact of the production process performance needs further study. These are the focus of our future research
Contact Person: Ms. Rainbow Li