The materials in the hopper are evenly spread on the mesh belt by the feeder, and the mesh belt is generally made of 12-60 mesh stainless steel wire mesh, which is dragged by the transmission device to move inside the dryer. The belt dryer consists of several units, each with independent hot air circulation. Some of the exhaust gas is discharged by a dedicated dehumidification fan 4, and the amount of exhaust gas emitted by each unit is controlled by a regulating valve.

In the upper circulation unit, the air from the circulating fan 5 enters the lower chamber of the unit through the surrounding air duct. The airflow is heated by the heater 7 and distributed by the distributor 6, forming a jet flow that blows towards the mesh belt, passes through the material, and enters the upper chamber. The drying process of the spray dryer is that hot air flows through the material layer to complete the process of heat and mass transfer. The upper chamber is connected to the fan inlet by the air duct. Most of the gas is circulated, and a portion of the gas with lower temperature and higher moisture content is discharged as exhaust gas through the dehumidification pipe, regulating valve, and dehumidification fan.

In the lower circulation unit, the air from the circulating fan first enters the upper chamber, is heated by the heat exchanger downwards, passes through the material layer and enters the lower chamber. The lower chamber is connected to the fan through side air ducts and return air ducts, and most of the gas circulates while a portion is discharged. The upper and lower loop units can be flexibly equipped according to user needs, and the number of units can also be selected according to requirements.