Classification type of drying equipment:
1. According to operating pressure
According to the operating pressure, the dryer is divided into two types: normal pressure dryer and vacuum dryer. Operating under vacuum can reduce the partial pressure of wet steam in the space to accelerate the drying process, and can reduce the boiling point of wet moisture and the drying temperature of the material. Steam is not easy Leakage, so the vacuum dryer is suitable for drying heat-sensitive, easily oxidized, explosive and toxic materials and moisture vapor needs to be recovered.
2. According to heating method
According to the heating method, the dryer is divided into convection type, conduction type, radiation type, dielectric type and other types. Convection dryers, also called direct dryers, use hot drying media to directly contact wet materials, transfer heat by convection, and take away the generated steam; conductive dryers, also called indirect dryers, use conduction The heat is transferred from the heat source to the wet material through the metal partition. The generated moisture vapor can be removed by vacuum suction, a small amount of purge gas, or condensation on the surface of a separate low-temperature condenser. This type of dryer does not use a drying medium, the thermal efficiency is high, and the product is not contaminated, but the drying capacity is limited by the heat transfer area of the metal wall, the structure is more complicated, and it is often operated under vacuum; the radiant dryer uses a variety of radiation The device emits electromagnetic waves in a certain wavelength range, which is selectively absorbed by the surface of the wet material and converted into heat for drying; the dielectric dryer uses the action of a high-frequency electric field to cause the heat effect inside the wet material to dry.
3. According to the movement mode
According to the movement of wet materials, the dryer can be divided into fixed bed, agitated, spray and combined; according to the structure, the dryer can be divided into box dryer, conveyor dryer, drum dryer, vertical There are many types of dryers, mechanical agitation dryers, rotary dryers, fluidized bed dryers, airflow dryers, vibration dryers, spray dryers and combined dryers.