Freeze Microwave Dryer Equipment
With the development of technology, drying technology has also made great progress, not only limited to traditional drying methods, but also incorporate some means to improve drying efficiency. In recent years, microwave freeze-drying technology is more popular. It is also because of the development of microwave freeze-drying technology, which has brought broad development space for food industry production.
Vacuum freeze-drying technology can better retain the active ingredients in materials, but because the freeze-drying device uses the traditional heating method, freeze-drying also has the shortcomings of low drying rate, long time and high energy consumption. Freeze microwave dryer equipment is a new technology which combines high-efficiency microwave radiation heating technology with vacuum freeze-drying technology and has great application value . Microwave heating is based on the principle of dielectric heating, which has the characteristics of rapid heating, uniform heating, energy saving and high efficiency, high heating quality and less nutritional damage. With the development of food industry, food drying technology is particularly important, especially by using newer and more advanced means, its production efficiency can be improved. However, the commonly used drying technology can not meet the needs of industrial efficiency because of various limitations, so the microwave freeze-drying technology has been greatly developed.
With the development of drying technology, main technologies such as heating and drying, vacuum drying, spray drying, freeze drying, microwave freeze drying and other main drying technologies are commonly used nowadays. Microwave freeze drying technology combines the advantages of previous freeze drying technology to use microwave as a heat source, thereby improving efficiency and reducing energy consumption.Microwave is a kind of electromagnetic wave, which can produce high frequency electromagnetic field. Polar molecules in dielectric materials change their polar orientation with the frequency of electromagnetic field, which makes molecules vibrate back and forth and generates friction heat. Because of the large loss of liquid water medium in wet materials, microwave energy can be absorbed and transformed into heat energy, which makes the temperature of materials gradually increase, and microwave heating can make the objects uniformly heated . Moreover, microwave heating has a non-thermal effect. The freeze drying device mainly includes refrigeration system, vacuum system, water catching system and heating system. Conventional heating methods always depend on internal and external temperature gradient to heat transfer, so the surface temperature is higher than the internal temperature, and the heat transfer speed of this kind of heat transfer mode will be very slow, so microwave freeze-drying technology is to use microwave in heating system to improve the heating rate.
Microwave freeze-drying technology does have some advantages mentioned above, but there are still some key technologies that have not been solved in practical operation. At present, the main problems of microwave freeze-drying technology are glow discharge, temperature on-line detection, drying end point discrimination, etc. The most prominent problem is glow discharge. In order to solve this problem, vacuum must be controlled. Because the gas in vacuum is easy to produce high frequency discharge when it is diluted to a certain extent, so vacuum should be chosen at the critical value of gas ionization.In a word, microwave freeze-drying technology still has a great development space. As long as these limitations are solved and it can be widely applied, it will have unprecedented market potential and its prospects will be more open.