Working principle of dryer

The working principle of the dryer is to evaporate the moisture in materials with high humidity through heating, ventilation, etc. to achieve the drying effect. The principle of a dryer is based on the interaction of a series of physical, chemical and mechanical processes. Depending on the drying method, the dryer can be divided into a direct dryer and an indirect dryer 7. Here are the working principles of several common dryers:

Conductive drying: Place the material on a heating plate and heat the material through the heating plate to evaporate the moisture or other liquid inside it. This drying method is suitable for some relatively small materials, such as powders, granules, etc. The heating plate is usually composed of an electric heating tube or a steam heating tube. The heating plate is heated through the heating tube to heat the material.

Convection drying: Place the material in the drying chamber, and make it hot air by heating the air in the drying chamber, and then blow the hot air onto the material through a fan in the drying chamber, thereby heating the material to evaporate the moisture or other liquid inside it. A convection-drying drying chamber is usually composed of a heater, a fan, a filter, etc. The air is heated through a heater, and then the hot air is blown onto the material through the fan.

Refrigerated drying: consists of three parts: heat exchange system, refrigeration system and electrical control system. The compressed air first enters the precooler for heat exchange of gas-gas or gas-water, removes part of the heat energy, and then enters the hot and cold air exchanger, and exchanges heat with the cold air that has come out of the evaporator to be cooled to the pressure dew point, further reducing the temperature of the compressed air.

Spray drying: The material to be dried is sprayed into tiny liquid droplets and contacts with high-temperature air to quickly evaporate moisture, thereby achieving drying of the material.

Vacuum freeze-drying: Under a vacuum low-temperature environment, the moisture content in the material is frozen into a solid, and then turned into gas to sublimate, thereby obtaining the freeze-dried material.

The above are the working principles of several common dryers. It should be noted that different types of dryers are suitable for different materials and occasions. When selecting a dryer, it is necessary to determine the appropriate type and parameters based on the characteristics of the material and the drying requirements.