Microwave drying is a new type of drying. When drying, the microwave energy directly acts on the medium molecules to convert into heat energy. Since the microwave has the penetrating property to simultaneously heat the inside and outside of the medium, heat conduction is not required, so the heating speed is very fast, and the drying speed can be shortened for foods with water content below 30%. Hundreds of times. At the same time, regardless of any shape of the object, due to the simultaneous heating inside and outside the medium of the object, the temperature difference between the inside and the outside of the material is small, the heating is uniform, and the condition of external coke in the conventional heating does not occur, so that the drying quality is greatly improved.
Microwave is a kind of high-frequency wave that changes at a speed of 2。4 billion times per second, causing high-speed yaw motion of water molecules。 They rub each other to generate great heat and can easily dry materials。
Microwave drying equipment has the following advantages over conventional heating:
1, uniform and fast, which is the main feature of microwave drying. Since the microwave has a large penetrating power, heat can be directly generated inside the medium when heated. Regardless of the complexity of the shape of the material, the heating is even and fast, which allows the material to dehydrate quickly.
2. It is selective. Microwave heating is related to the nature of the material. In a microwave field of a certain frequency, water is much larger than other materials because of its dielectric loss, so the moisture is much larger than that of other dry materials. The heating is carried out simultaneously in the table, and the internal moisture can be quickly heated and evaporated directly so that the material can be demolded by heating in a short period of time.
3, high thermal efficiency, sensitive response, because the heat directly comes from the inside of the dry material, the loss of heat in the surrounding medium is very small, plus the microwave heating chamber itself does not absorb heat, does not absorb microwaves, all emissions act on the material, high thermal efficiency.
After the object absorbs microwave energy and converts it into heat, the temperature of the object rises, and the water contained in the object evaporates, dehydrates and dries; if the dehydration speed is properly controlled, the structure of the object can be loosened and puffed when the material is dried. In this process, it is also possible to control the heating temperature to make the object in a baked state.
Microwave drying equipment is widely used in chemical raw materials, food, medicine, agricultural and sideline products and other fields that need to be dried。