Views: 0 Author: Site Editor Publish Time: 2023-04-19 Origin: Site
Low temperature and high efficiency:
It is well known that when atmospheric pressure decreases, the boiling point of water decreases. For example, at an atmospheric pressure (101.3 kpa), the boiling point of water is 100℃, while at 0.073 atmospheric pressure (9.37 kpa), the boiling point of water is 40℃. Under vacuum conditions, heating an object can cause the moisture inside the object to evaporate without heating up. Microwave vacuum drying of heat sensitive substances is much faster than conventional drying, with a ratio of typically more than a dozen or even dozens.
The parts with high water content absorb more microwaves and generate more heat, while the parts with low water content generate less heat; At the same time, the product is internally and externally heated as a whole, without thermal inertia and heat transfer loss, and fast drying speed. 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 temperature gradients that create "shells" that slow water evaporation.
Due to the characteristics of rapid adjustment of microwave power and inertia free, combined with PLC automatic control and timely control, it is convenient for the adjustment and determination of process parameters.
Drying in a low temperature and oxygen free environment can better ensure product quality.
Maintaining the primary color:
Due to the short drying time of microwave, it solves the problem of discoloration caused by long traditional drying time and high humidity. It is an ideal drying method especially for precious medicinal materials (Cordyceps sinensis, Ginseng), traditional Chinese medicine extracts, and seafood products (sea cucumber, etc.).
Energy conservation and environmental protection:
Compared to conventional electric heating drying methods, microwave drying can generally save power 50%. The equipment uses microwave radiation to transfer energy, and it is used for overall heating of the medium, eliminating the need for other heat transfer media, avoiding the disadvantage of slow heat transfer under vacuum conditions. Therefore, the speed is fast, the efficiency is high, the drying cycle is greatly shortened, and the energy consumption is reduced. There is no noise, no toxic gas emissions, no toxic liquid emissions, and it is an environmentally friendly drying technology.
Summary: From the characteristics described above, it can be seen that the remarkable economic and social benefits from the aspects of uniform and thorough drying, energy conservation, emission reduction, improving product quality and yield, safety and health, etc.