The function of the Dryer Equipment is to remove the moisture in the raw materials, finished products, and semi-finished products, making the materials convenient for manufacturing, packaging, storage, transportation, etc., facilitating subsequent processing and use, and achieving the purpose of improving and increasing the value of the product.
There are two ways to dry the material:
1. Provide heat energy to vaporize the water after absorption, and become separated water vapor.
2. Try to eliminate water vapor directly.
The methods of providing heat energy include convection, conduction, and radiation. The method of removing water vapor is to use air as a carrier to take away water vapor or use vacuum to directly remove water vapor. Therefore, the basic drying methods include: normal pressure convection, normal pressure conduction, normal pressure radiation, vacuum conduction, and vacuum radiation. In actual engineering, according to different heat energy and heating methods, the drying methods are divided into the following types:
- Air dry
The heated hot air is used to bring heat into the container to transfer the heat to the material. This uses convection to transfer heat to provide heat to the wet material, so that the moisture in the material is vaporized to form water vapor, and the water vapor is taken away to produce a drying effect. This method is widely used in hot air dryers, European standard dryers, dehumidifying dryers, drying ovens, air drying, boiling drying, spray drying...etc.
- Heat Transfer and Drying on Heating Surface
Use the material to contact the heat conduction surface, and then use the air to take away the water vapor to produce a drying effect, such as vacuum dryers, horizontal heating mixing barrels... etc.
- Infrared Drying
Use infrared radiation as a heat source to supply heat. According to the wavelength, it can be divided into near-infrared and far-infrared. In the molecular region of infrared motion frequency, heat can be safely transferred, and it is hygienic and fast in drying. This method is mostly used in vegetables and fruits. , Flowers and wood continuous drying equipment.
- Microwave Drying
Under the action of the microwave magnetic field, the inside and outside of the material are vibrated at the same time, and the vibration energy makes the material heat up, so as to achieve the purpose of vaporizing and removing water. This method has simple equipment, high heat energy utilization, short drying time, and good drying quality. However, the disadvantages are high investment, high power consumption, and leakage of magnetic waves must be prevented.
- Frozen Sublimation and Drying
The material is frozen to the freezing point and the water freezes, and then the ice is directly sublimated into water vapor under a higher vacuum degree and then the water vapor is removed. Because it is dried at low temperature, the original characteristics of the material can be preserved. Therefore, it is used in the health food industry. Various vegetables, fruits, flowers, oils... etc. are widely used.