What is the working principle of belt dryer

The working principle of the belt dryer is that the material is evenly laid on the mesh belt by the feeder, and the mesh belt adopts 12-60 mesh stainless steel wire mesh It is moved in the dryer by the driving device The dryer is composed of several units, each unit has its own hot air circulation, part of the tail gas is discharged by a special exhaust fan, and the waste gas is controlled by a regulating valve The hot gas passes through the materials laid on the mesh belt from the bottom to the top or from the top to the bottom, and is heated and dried to take away the moisture The net belt moves slowly, the running speed can be adjusted freely according to the material temperature, and the dried product falls into the feeder continuously The upper and lower circulation units can be flexibly equipped according to the needs of users, and the number of units can be selected according to the needs The material in the hopper is evenly spread on the mesh belt by the feeder, and the mesh belt generally adopts 12-60 mesh stainless steel mesh, which is dragged by the drive device to move in the dryer The dryer is composed of several units, each of which circulates the hot air independently Part of the tail gas is discharged by the special exhaust fan 4, and the exhaust gas volume of each unit is controlled by the regulating valve In the upper circulating unit, the air from the circulating fan 5 enters the lower chamber of the unit from the side air duct, and the air flow is heated up through the heater 7 After being distributed by the distributor 6, the air flows into the mesh belt in jet flow, and enters the upper chamber after passing through the materials The drying process is a process in which hot air flows through the material layer to complete the heat and mass transfer The upper chamber is connected with the fan inlet by an air duct Most of the gas circulates, some of the gas with lower temperature and larger moisture content is discharged as exhaust gas through the dehumidification pipe, regulating valve and dehumidification fan In the lower circulating unit, the air from the circulating fan enters the upper chamber first, then it is heated by the heat exchanger downward and enters the lower chamber through the material layer The lower chamber is connected with the fan by the side air duct and return air pipe Most of the air circulates and some is discharged The upper and lower circulation units can be flexibly equipped according to the needs of users, and the number of units can also be selected according to the needs It is used for dehydrated vegetables and three equipment are generally used in series to form primary, intermediate and final drying sections In the primary dry section, due to the high moisture content of the material Poor air permeability, so the use of a smaller thickness, faster running speed and higher drying temperature In the primary drying section, the temperature of drying gas can be as high as 120oc The retention time of the material in the final dry section is 3-6 times of that in the initial dry section, and the thickness of the paving material is 2-4 times of that in the initial dry section For the requirement that the material temperature does not exceed 60oC, a dry gas of about 80oC can be used The use of multi-stage combination can better play the performance of belt dryer, and drying more evenly.