As early as the 1980s, western developed countries have begun to develop equipment such as industrialized microwave vacuum dryers, and have achieved good results in practical applications. France International Microwave Co., Ltd. uses microwave vacuum drying equipment to process seedless raisins, changing the traditional process of 65°C, 24-hour hot air drying to 50°C, 5-hour microwave vacuum drying, which greatly improves product quality and output.
The following are several advantages of microwave vacuum low temperature drying:
1. High-efficiency conventional vacuum drying equipment uses steam for heating, which needs to be heated from the inside to the outside. The slow heating speed requires a lot of coal consumption, while the microwave vacuum drying equipment uses electromagnetic wave heating, without heat transfer medium, directly heating to Inside the object, the heating speed is fast. 1 kilowatt of microwave can heat the water at room temperature to 80°C within 3-5 minutes, avoiding the above shortcomings, so the speed is fast, the efficiency is high, the drying cycle is greatly shortened, and the energy consumption is reduced.
Compared with conventional drying technology, the work efficiency can be improved by more than four times.
2. Heating evenly
Due to microwave heating, the material is heated from the inside to the outside at the same time, the temperature difference between the inside and outside of the material is very small, and the inconsistency between the inside and outside heating that occurs in conventional heating will not occur, resulting in the effect of puffing, which is conducive to crushing and greatly improves the drying quality. .
3. Easy to control, convenient for continuous production and automation
Because the microwave power can be adjusted quickly and has no inertia, it is easy to control in real time, and the temperature can be adjusted arbitrarily between 40°C and 80°C.
4. The equipment is small in size, easy to install and maintain, and does not need to occupy too much space.
5. Good product quality
Microwave vacuum drying equipment can extend the shelf life of food, preserve the original flavor and nutritional content of food, retain the physiological activity of raw materials, enhance the functionality of health food, and increase the added value of agricultural products. Compared with conventional methods, the quality of processed products is greatly improved.
6. Microwave has the effect of disinfection and sterilization, and the product is safe and hygienic. Long shelf life.
7. Significant economic benefits.
Traditional drying takes a long time, is very slow, consumes a lot of energy, and has high processing costs. Using microwave heating can save a lot of energy and increase the speed of heating and drying. This is because microwaves are penetrating, and do not require any medium when heating objects, and can heat both inside and outside of the material.
According to domestic and foreign data, using microwave equipment to heat materials, its speed and efficiency are 4 to 10 times that of conventional heating methods.
From the characteristics introduced above, it can be seen that its economic and social benefits are remarkable in terms of energy saving, consumption reduction, product quality improvement, safety and sanitation, and low equipment investment costs. The invention of the microwave vacuum dryer will provide a modern high-tech drying equipment for many fields of our country's national economy and scientific research departments.