Drum dryer (also known as drum dryer, rotary dryer, etc.) is a kind of contact type internal heating conduction drying machinery, widely used in chemical industry, brewing, manufacturing, pharmaceutical, fertilizer, municipal sludge treatment and other aspects. In the drying process, heat is transferred from the inner wall of the drum to its outer wall, passing through the dried food materials attached to the outer wall of the drum, and evaporating the moisture on the materials. It is a continuous drying production machinery.