The tumble dryer is a kind of drying equipment with early application time and wide application range in China. It mainly uses different types of lifting plates internally to exchange heat between materials and hot gases, so that the materials are dried. The utility model has the advantages of good adaptability to materials, simple structure, reliable operation and large production capacity. Its shortcoming is that the drying efficiency is low, the thermal efficiency is only 0.35~0.65, the consumables are large, the floor space is large, and the investment is more. The newly developed double-barrel rotary dryer has the advantages of strong adaptability, not easy to block material, small floor space, less heat loss, and unique lifting plate design to make the thermal efficiency higher. The sleeve type structure design has less heat loss, high heat transfer efficiency and is more conducive to material drying. When the material is directly dried by the hot air flow in one cylinder, it is indirectly dried by the heat in the other cylinder, and the low temperature outer cylinder has heat insulation effect on the high temperature inner cylinder. The heat exchange between the material in the inner cylinder and the hot gas is mainly radiation and convection heat transfer; in the outer cylinder, the hot gas has a high humidity and the temperature is low, and the material is scattered on the outer wall of the inner cylinder, and the heat exchange is performed by heat conduction. Convection is equally important. Generally, the surface temperature of the cylinder of the single-cylinder rotary dryer reaches 110-120 ° C, while the surface temperature of the outer cylinder of the double-tube rotary dryer is only 60-70 ° C, the heat loss is reduced, and the energy saving effect is obvious. The feeding end adopts a forward spiral lifting plate, so that the lifting plate can be warmed into the drying stage after preheating. The lifting device enables the material to "squirm" forward in the form of a "wave" in the axial direction. It has the functions of guiding, current sharing and material blocking. The uniformity of material spreading is increased and the material retention time and the number of material turnovers are increased, and each set of the lifting plate in the new lifting device has an angular misalignment in the radial position. And in the center position, a "10,000-shaped" multi-layered lifting and spreading device is set. Through the change of its angle and the rotation of the cylinder, the material is repeatedly thrown on the cross section of the cylinder, showing a "waterfall"-like drop in the shaft. The upward rows of the lifting plates are arranged at the same time, complementing each other, avoiding the "wind tunnel" and the "stairs spreading", and playing a certain crushing effect. Increase the contact area between the material and the hot gas stream, thereby greatly improving the drying efficiency. The structure is compact, the process layout is flexible, and the civil construction investment is small. Under the premise of ensuring the time required for the material drying process, the length of the whole machine is shortened by about 40%, which is beneficial to the process layout. At the same time, it reduces the building area of ​​the plant and saves about 30% of the project investment, which is more suitable for the process layout of the old factory renovation. The transmission has been greatly improved. The machine cancels the large and small gear transmission, adopts the four-spindle edge synchronous transmission, the structure is more compact, the installation and maintenance are more convenient, and the operation rate is higher. The material and the hot air flow are used in the downstream drying process, and the application range is wide. The double cylinder dryer is suitable for drying various raw materials such as clay, coal, slag and iron powder, and is also suitable for drying various bulk materials in metallurgical, chemical and other departments to maintain the original activity of the materials. The speed control motor is used to adjust the cylinder speed and automatic temperature monitoring system. Make the operation more convenient. According to the initial moisture content of the incoming materials, the final water output, and the production requirements, the appropriate speed can be used to ensure the demand of the next process. Optimized structural design and wear-resistant treatment ensure the service life of the equipment. The inlet between the ring is made of imported wear-resistant steel plate, the feed hopper is applied with stepped material lining structure, the feeding cone and the inlet tube are made of heat-resistant steel plate, which lays a solid foundation for long-term safe and trouble-free operation.