Using high-temperature flue gas, the ore tube dryer is suitable for the fine materials, such as the wet-clean coal. The ore tube dryer has high drying speed because of the relatively large contact surface of the hot flue gases and materials. Tube dryer is of low thermal efficiency ,high power consumption and relatively large drying cost , but it belongs to less investment equipment and contains large unit volume vaporized water. It is easy to manufacture and repair ,and the steel consumption is low.
The tube drying machine may be pided into several sections, while the diameter and the length of the drying duct are based on the requirements of production and product moisture, the diameter increases with the increasing of production volume, the lower product moisture the products has, after drying, the longer the drying tube will be . Spiral sweeper is composed of the screw axis, helical blade, and it can send the coal into the dust collector. The transmission gear includes gear motor, reducer, drive pulley and V-belt bulk, the wet coal can be sent evenly into baking trunk by the coal device.
High temperature hot flue gas from the lower part of the drying tube is fed into the drying tube, high temperature and high flue gas in the drying tube makes the mineral material in suspension and rise along the drying tube. Vaporized steam and the exhaust gas will be discharged together into the precipitator. In the drying duct, the fine-grained light materials will rise with the speed, which is the same with that of the flue gas . The rising speed of the large coarse materials is lower than the flue gas velocity, and thus it has longer residence time in the drying tube, the flue gas velocity of the drying equipment should be less than 25 to 35m / s.