Roller dryer Description After the damp raw material is put into the drier from on end, it is turned over through strring-up rake inside the cylinder and distributed uniform in the drier and contacted with countercurrent hot air fully. It speeds up heat and mass conducting of dry. During the oeriod of dry, raw material is effcted by stirring-up rake with gradient and hot air, it can be moved and passed through the dry region and to star valve and then discharge the finished product.