Microwave drying machine
Electromagnetic radiation drying is to use the electromagnetic induction or infrared radiation effect of microwave to heat and dry materials. Different from other external heating drying methods, this drying method is a method of uniform heating from both outside and inside of the material. Therefore, this drying method has a short time, does not deteriorate or coke due to overheating, and its drying products are of good quality, especially the drying effect of heat-sensitive food is more satisfactory.
The basic properties of microwave are usually presented as penetration, reflection and absorption. For glass, plastics and porcelain, microwave almost passes through without being absorbed. For water and food, they absorb microwaves and heat themselves. For metals, microwaves are reflected.
Microwave drying equipment, also known as microwave dryer, is a kind of microwave dryer used to dry food, medicinal materials, wood, building materials, cardboard and other materials. Compared with traditional drying equipment, the characteristics of plastic bag microwave drying machine is: fast drying speed, high efficiency, environmental protection and energy saving, and it is a new type of equipment responding to low-carbon economy. Its working principle is to use the penetrating heating of microwave to raise the temperature of material, vaporize and evaporate the water in the material, and evaporate the water vapor from the dehumidification system to achieve the purpose of drying materials.
Microwave is a kind of electromagnetic wave with very short wavelength (that is, the range of electromagnetic wavelength from 1mm to 1m). It belongs to electromagnetic wave as radio wave, infrared ray and visible light. Microwave is a penetrating electromagnetic wave with frequencies ranging from 300 MHz to 300 MHz. The commonly used microwave frequencies are 915 MHz and 2450 MHz. Tunnel microwave dryer heating technology depends on the microwave penetrating the material at a speed of several hundred million times per second, interacting with the polar molecule of the material. After the polarity of the material (such as water molecule) absorbs microwave, it changes its original molecular structure and makes the polar motion of the electric field at the same speed, resulting in frequent collisions between them, resulting in a large amount of friction heat. In order to achieve the purpose of heating and drying, each part of the material is heated at the same instant to generate heat, expansion and water evaporation.
Microwave is absorbed in the fast changing high frequency electromagnetic field and interacts with material molecules to produce heat effect. Microwave energy is directly converted into medium heat energy. After microwave is absorbed by the object, the object spontaneously generates heat. Heating starts from the inside and outside of the object at the same time. Different substances can simultaneously heat both inside and outside. Different substances have different abilities to absorb microwave, and their heating effects are also different. This mainly depends on the dielectric loss of the substance. Water is a substance that absorbs microwave very strongly. Generally, substances containing water can be heated by microwave, which is fast and uniform, and achieves good drying effect.
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