Sludge is a solid precipitate produced by water and sewage treatment processes. Its main characteristics include high moisture content, high organic matter content, easy decay and odor, fine particles, small specific gravity, and a gel like liquid state. Sludge is mainly divided into domestic sewage sludge, industrial wastewater sludge, and water supply sludge according to their sources. The disposal and treatment of various types of sludge has become a persistent problem that restricts urban development and urban hygiene.

　　A small sludge dryer is an indirect heating low-speed stirring type dryer, which has two or four hollow rotating shafts inside the equipment. The hollow shafts are densely arranged in parallel with fan-shaped wedge-shaped hollow blades, and the structural design is special and clever. The relative rotation of the shaft body cleverly achieves the self-cleaning effect of sludge on the shaft body by utilizing the principle and structure of the same angular velocity but different linear velocities, greatly preventing the phenomenon of holding the shaft during the sludge drying process.

　　Below, we will introduce the characteristics of small sludge dryers:

　　1. As the heat required for equipment drying relies on indirect heating through thermal conduction, the drying process does not require or only requires a small amount of gas to remove moisture. It reduces the heat loss carried away by the airflow and improves the heat utilization rate, making it an energy-saving drying equipment.

　　2. Mixing and stirring cause the material to vigorously flip, resulting in a high heat transfer coefficient. Therefore, the occupied area and space are very small, saving on the cost of factory construction. The drying process has low gas consumption, low flow rate, and less dust carried away by the gas. Therefore, the recovery of gas dust after drying is convenient, and the recovery equipment has a small volume, which can save equipment investment. For drying processes that require solvent recovery, solvent concentration can be greatly increased. Due to the unique structure of the propeller blades, the material undergoes alternating squeezing and relaxation during the drying process, enhancing the drying process. The filling rate of materials in the drying room is very high, reaching 80% -90%. The residence time of materials can be adjusted by adjusting parameters such as feeding speed, stirring shaft speed, and material filling degree, from a few minutes to several hours.

　　3. It can be used for sludge drying in various fields such as municipal sludge, printing and dyeing sludge, papermaking sludge, electroplating sludge, etc. It has high thermal efficiency, a wide range of applications, low operating costs, and can also achieve continuous production.