Method and device for drying granular, capillary-porous materials and agricultural products

The invention relates to a method and a device for drying granular, capillary-porous materials and agricultural products in a dryer with a material flow due to gravity. The dryer is equipped with ducts (3, 4) for blowing in and out the drying medium. … The essential feature of the method consists in that the lower, open side of the blowing-out duct (4) is terminated close to the drying medium outlet with a flow-directing insert (6). The blowing-out ducts (4) are connected to a transfer duct (13) and the latter is connected to the hot drying medium flow via a shut-off device, preferably a flap (18). The shut-off device (18) is controlled via difference signals of two temperature or moisture sensors (15, 16) mounted at different dryer heights. In order to avoid overdrying, the capacity of the dryer is reduced if necessary, the operation of some blowing-in duct groups being switched off by shutting off the access openings. … The angle of inclination of the side surfaces of the blowing-in and blowing-out ducts is at most as large as the natural angle of incline of the product to be dried. The flow speed of the drying medium is in the ducts at least 13 m/s and at least ten times the flow speed of the drying medium inside the product. Arranged in the blowing-out ducts (4) is a flow-directing insert (6), the size of which ... … Original abstract incomplete. ……