How do Different Types of Industrial Dryers Work?

Both double drum dryer and triple drum dryer are quite commonly applied industrial dryers in the mining industry. So how do these two types of dryer work in fact?

Double drum dryer:

When the temperature arrives at 400℃-800℃ at the bottom, materials are lifted into the drum by the elevator through the feeding mouth, then get scattered and crushed under the gravity effect, and then flowed inside the drum.

The hot air from the bottom air heater of the double drum dryer rising from bottom to top meets the materials and transmits the heat to them by way of heat conduction, convection and radiation. Materials get hotter and hotter and the moisture gets vaporized; finally the materials are discharged from the bottom and the air with water vapor is ejected from the balcony by the exhaust fan.

Triple drum dryer:

Materials enter the inner side of the drum through the feeding device to realize current flow drying process. They get raised and scattered under the shoveling plate in a spiral advancing way to exchange heat.

Then the materials enter the middle layer of the inner wall through the other end to realize counter current drying process. They are lifted in over and over in the middle layer which advance in two-steps forward and one-step back way.

Finally, materials fall into the external layer of the drum from the other end of the middle layer, processing in a rectangle multi-loop way. Materials are dried completely inside the rectangle shoveling plate and then cooled by the single drum cooler, thus finishing the whole drying process.