The design of the dryer machine must be able to reflect the principle of hot air all-round and three-dimensional smooth flow. Moreover, the flow direction of the hot air should be perpendicular to the moving direction of the dough. The hot air flows from the top to bottom, which reduced the flow resistance, exhaustive and uniform drying.
With regard to the roller dryer, under the role of negative pressure, the natural inhalation of the fresh air through the head of the dryer and the opening of the lower part are conducive to recycle the exhaust gas. Using the waste heat of the exhaust heat to preheat the fresh air, which is helpful to energy conservation and improve the thermal utilization efficiency. There is moisture removal pipe on the top of the roller dryer, whose height is about 6 ~~ 7m. The moisture removal pipe takes advantage of the thermal air pressure differential to discharge the moist air. In addition, a damper is installed on the moisture removal pipe, which helps to adjust and control the emissions of the wet air in accordance with the changes in the weather and production requirements.
The roller dryer adopts the concurrent heating and its heat source is from the combustion device, the dryer downstream heating. Due to the tilted position, on the one hand, the materials flow to the back-end under the role of gravity and rotary effect, on the other hand, the materials are lifted by the shoveling plate repeatedly, up to the upper end and then be scattered constantly so that the material in the barrel can form a uniform curtain, which helps the materials to conduct heat exchange with the hot gas stream of the barrel fully and completely. Because the materials are scattered repeatedly, the moisture contained is dried gradually so as to achieve the purpose of drying.