| 摘要 |
<p>The apparatus comprises a drying enclosure (10), open-ended inlet and outlet ducts (11, 12) communicating with the enclosure, and conveyors (13, 14, 15) for conveying the material to be dried along the inlet duct, through the enclosure and along the outlet duct. Superheated steam is generated in the enclosure from the moisture in the material (19) being dried by circulating the initial gas within the enclosure between a heat source (23) and the material, and/or by the injection into the enclosure of superheated steam from an external source. The inlet duct (11) and outlet duct (12) both extend downwardly from the enclosure (10) and a vent duct (22) from the enclosure has an outlet (26) normally at a level midway along the two ducts. In use, superheated steam tending to pass downwardly along the ducts meets external air tending to pass upwardly along the ducts and forms within each duct a temperature and density differential stratification layer (21). These layers act as barriers to the escape of steam from the enclosure while at the same time permitting the free conveyance of material along the ducts and into and out of the enclosure (10).</p> |
