What are the differences in working principles between different types of industrial dryers?

Industrial dryers play an important role in different industries and application scenarios. They are of various types and have different working principles. According to the drying method, heat source type and material processing method, industrial dryers can be divided into many types, each of which has its own unique working principle and scope of application.
Hot air circulation dryer is a common industrial drying equipment, which mainly relies on hot air to circulate in the drying chamber to remove moisture from the material. This dryer is usually equipped with a heating system to heat the air and enter the drying chamber to fully contact the material, thereby evaporating the moisture. The hot air is repeatedly used through the circulation system, which improves the thermal efficiency and reduces energy waste. During the whole process, the dehumidification system will continuously discharge the wet air to maintain the dry environment in the drying chamber. This drying method is suitable for many industries, such as food processing, textile processing and agricultural product drying.
The working method of the drum dryer is different from that of the hot air circulation type. Its core component is a rotating drum, in which the material is constantly tumbling and heated by hot air. The hot air is usually provided by a combustion device or an electric heating device, and the heat is transferred through the inside or outside of the drum to gradually dehydrate the material. Due to the rotary motion of the drum, the material can be heated evenly, thus achieving a higher drying efficiency. Drum dryers are particularly suitable for granular, powdered or block materials, such as ores, feed, building materials, etc.
The characteristic of vacuum dryers is that they can complete the drying process under low temperature conditions, which is suitable for heat-sensitive materials. Under vacuum conditions, the evaporation temperature of water will decrease, so the water can be removed at a lower temperature, thus avoiding damage to the material by high temperature. This type of dryer is commonly used in the pharmaceutical, chemical and food industries, such as drying food that needs to maintain nutritional content, or low-temperature drying of medicines. The entire system needs to maintain a high degree of sealing to ensure the stability of the vacuum environment, and use a vacuum pump to continuously extract water vapor to improve the drying efficiency. Different types of industrial dryers have their own characteristics, and the selection of suitable equipment requires comprehensive consideration based on the specific material properties, production needs and drying requirements. Regardless of the drying method, reasonable temperature control, uniform heat distribution and effective moisture removal are important factors to ensure the drying effect.