Abstract

The moisture content of tobacco, particularly greenleaf tobacco, is reduced to an accurately determined value by conveying a continuous tobacco stream through three successive sections of a transporting system wherein the tobacco is contacted by air currents. In accordance with a first embodiment, a relatively hot current of air is conveyed countercurrent to the direction of tobacco transport in the first section of the transporting system; in the second section, the flow of hot air is concurrent with the direction of tobacco transport; in the third section, the tobacco is contacted by relatively cool air having a relatively high moisture content. The air which is conveyed through the third section can be withdrawn from the first section, and the temperature of air in the second section is regulated as a function of deviations of moisture content of partially or completely conditioned tobacco from a desired moisture content. The temperature and moisture content of air in the third section are maintained at a constant value to bring about a hygroscopic equilibrium between air and tobacco particles in the third section. In accordance with a second embodiment, the particles of tobacco are subjected to the homogenizing action of moist air currents in the third and/or first section of the transporting system whereby the homogenizing of tobacco in the first section insures that tobacco entering the second section has a uniform moisture content and the homogenizing in third section compensates for eventual lack of uniform drying action in the second section.