Dryer working principle: dry and wet material by belt conveyor and bucket elevator to the hopper, and Hopper Feeder through feeding tubes into the feeding end. Feeding the natural inclination of the slope of the pipeline than materials, so that material flows smoothly in the dryer. Dryer drum is a slightly inclined rotating cylinder with horizontal lines. Sand equipment from high end joining, heat carrier from low-end entry, counter-current contact with the material, there is heat and materials together and flow into the cylinder.