Characteristics of microwave vacuum drying equipment:
1. Low temperature and high efficiency: as we all know, the boiling point of water decreases with the decrease of air pressure. For example, at one atmospheric pressure (101.3kPa), the boiling point of water is 100 ℃, while at 0.073 atmospheric pressure, the boiling point of water is 40 ℃. Under the condition of looking at the sky, heating the object can make the water inside the object evaporate without temperature rise. The drying speed of microwave vacuum drying of heat sensitive materials is also much higher than that of conventional drying, and the ratio is generally more than ten or even dozens.
2. Uniformity and thoroughness: the part with high water content absorbs more microwaves and generates more heat, whereas the part with high water content generates less; At the same time, the product is heated internally and externally as a whole, without thermal inertia, heat transfer loss and fast drying speed. The microwave directly penetrates the product, excites water molecules and generates heat. The internal temperature is slightly higher than the external temperature, which can avoid the disadvantage of "shell" due to temperature gradient and slow evaporation of water.
3. Simple control: because the microwave power can be adjusted quickly and has no inertia, it is controlled in time by PLC automatic control system, which is convenient for the adjustment and determination of process parameters.
4. Improve quality: drying in a low-temperature and oxygen free environment can better ensure product quality.
5. Keep the primary color: because the microwave drying time is short, it solves the problem that the traditional drying time is long and the humidity is high, which is easy to cause the product to change color. It is an ideal drying method for precious medicinal materials (Cordyceps sinensis, ginseng), traditional Chinese medicine extracts (extracts), seafood products (sea cucumber), etc.
6. Energy saving and environmental protection: compared with the conventional electric heating drying method, microwave drying can generally save 50% of electricity. The equipment uses microwave radiation to transfer energy, which is the overall heating of the medium, without other heat transfer media, and avoids the disadvantage of slow heat conduction under vacuum conditions. Therefore, the drying cycle is greatly shortened and the energy consumption is reduced. There is no noise, no toxic gas discharge, no toxic liquid discharge, which belongs to environmental protection drying technology.
From the above characteristics, it can be seen that the drying is uniform, thorough, energy-saving, emission reduction, improvement of product quality and yield, safety and health can be seen that its economic and social benefits are significant.