Technical principle of the hottest microwave heati

Technical principle of microwave heating and drying equipment

microwave heating technology is a new technology that uses electromagnetic waves to transmit energy to the interior of the heated object and heat it to meet the needs of production. The commonly used microwave frequencies are 915MHz and 2450MHz. Due to its high-frequency characteristics, it changes periodically at an amazing rate of billions of times per second. After the polar molecules in the material (typically water molecules, proteins, nucleic acids, fats, carbohydrates, etc.) absorb microwave energy, they show a trend of directional arrangement under the action of microwave, changing their original molecular structure. When the direction of the electric field changes, it also makes the polarity movement of the electric field at the same speed, which will cause the rotation of molecules, resulting in frequent collisions between molecules and a large amount of friction heat, which is expressed in the form of heat in the material, resulting in the rapid temperature rise, heating or aging of the material in a short time

at the same time, under the action of microwave, harmful bacteria, pests and other microorganisms in the material are affected by both non-polar thermal movement and polar rotation to change their arrangement and combination state and movement law, even if organisms are inactivated due to protein denaturation, and some hydrogen bonds of RNA and DNA in cells are relaxed, broken or recombined, interfering with or destroying their normal metabolism Heredity and proliferation, inhibit or kill the growth of bacteria and pests, and achieve the effect of insect killing, sterilization and preservation

characteristics of microwave heating:

(1) the heating speed is fast, because the microwave can penetrate into the interior of food materials, the drying speed is fast, and the irritability time is short, which only needs 1/10-1/100 (a fraction or a few times) of the traditional heating method; Therefore, the productivity is improved and the capital turnover is accelerated

(2) low temperature sterilization, keeping nutrition microwave heating sterilization is through the joint action of thermal effect and non thermal effect (biological effect), so compared with conventional thermal sterilization, it has the characteristics of low temperature and short-term sterilization. Therefore, it is not only safe and safe, but also can keep the nutritional components of food from being lost and destroyed, which is conducive to maintaining the original quality of products. The loss of color, fragrance, taste and nutrients is less, which is extremely beneficial to the maintenance of vitamin C and amino acids, which benefit from the acceleration of urbanization. Some experiments show that the chlorophyll, vitamins and other nutrients of fresh vegetables dried in the sun are only 3%, while they can be kept 17% when dried in the shade, 40% when dried quickly by hot wind, 60% when dried by microwave. 9 kelcai exhibition plays an important role in the local economy, 0%, and 97% when dried fresh by microwave sublimation

(3) heating uniform microwave heating, all parts of the object, regardless of their shape, can usually evenly penetrate the microwave to generate heat. Therefore, the uniformity is greatly improved. It can avoid the phenomenon of external coke endogenous, external dry and internal wet; It improves the product quality and is conducive to the formation of the quality of food materials

(4) heating and drying has the ability of automatic balance. Microwave has different effects on materials with different properties. Because water molecules absorb microwave best, the parts with high water content absorb more microwave power than the parts with low water content; The ability of water in the material to absorb microwave is stronger than that of dry matter, so the heating of water is higher than that of dry matter, which is conducive to the rise of water temperature, the evaporation of water, and the overheating of dry matter, which is extremely beneficial to reduce the damage of nutrition and flavor. The characteristics of selective heating are: automatically balance and absorb microwave to avoid coking when materials are heated and dried

(5) energy saving and efficient microwave has different effects on different substances. When microwave heating, the heated substances are generally placed in the heating chamber made of metal. The heating chamber is a closed cavity for microwave, and microwave cannot be leaked; The external heat dissipation loss is small, which can only be absorbed by the heated object. The air in the heating chamber and the corresponding container will not heat up, and there is no additional heat loss, so the thermal efficiency is very high; At the same time, the environment of the workplace will not be increased. If the environment is significantly improved due to the air mixed in the oil. The Institute of new energy vehicles is also vigorously trying and promoting spray free materials to save energy and electricity, which can generally save 30% - 50%

(6) it is easy to control and realize automatic production. As long as the control knob is operated, the microwave heating and drying equipment can instantly achieve the purpose of lifting and starting and stopping. Because during heating, only the object itself heats up, and there is no waste heat in the furnace body and the air in the furnace, so the thermal inertia is very small and there is no heat loss. The application of microcomputer control can automatically monitor the product quality, which is especially suitable for the automatic control of heating process and heating process specification

(7) improve the working conditions and save the floor area. The microwave heating equipment has no waste heat and sample pollution. It is easy to meet the requirements of food hygiene, and it does not heat or radiate heat. Therefore, the working conditions are greatly improved, and the equipment structure is compact, saving plant area

to sum up, the adoption of microwave heating technology has the advantages of fast, maintaining nutrition and flavor, uniformity, disinfection and sterilization, energy saving, sanitation, safety, pollution-free, efficient, convenient, controllable, small investment, conducive to improving product quality, extending shelf life, improving labor conditions, realizing production automation and so on. It is an advanced technology worthy of promotion