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.
Tunnel-type microwave drying and sterilization equipment can quickly dehydrate the paper with high moisture content, making the sealing paper compressive. As the name implies, the tunnel microwave dryer is the material passing through the conveyor belt of the microwave drying box, just like the concept in the tunnel. Material from the end of the feed, the end of the discharge, continuous operation of production. It is the main type of microwave drying equipment for continuous production of enterprises.
Principle of sterilization by tunnel-type microwave drying and sterilization equipment:
Microwave sterilization is the result of the combined action of thermal and biological effects of electromagnetic waves. Microwave thermal effect is a kind of condensed medium composed of water, protein, nucleic acid, carbohydrate, fat and liner. Under the action of strong microwave field, the temperature of the medium increases. Its spatial structure is changed or destroyed. Protein denaturation affects its solubility, viscosity, expansibility and stability, thus losing its biological activity.
Microwave sterilization and freshness preservation are the results of the combined effects of microwave heating and biological effects. The thermal effect of microwave mainly plays the role of rapid heating and sterilization, while the non-thermal effect uses protein and physiological active substances in microorganisms to mutate and lose vitality or death. Therefore, the microwave sterilization temperature is lower than the conventional method. Conventional methods of sterilization temperature to be more than 100 degrees, time to 10 minutes to dozens of minutes, while microwave sterilization temperature is only 70 to 90 degrees, time is about a few minutes.
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