Abstract: A continuous stream of tobacco particles is conveyed through a conditioning zone wherein the stream is agitated and is directly contacted by a current of hot air. The moisture content of the thus dried tobacco particles is measured downstream of the conditioning zone and the temperature of hot air is changed when the measured moisture content of dried tobacco particles deviates from a desired value. A second parameter of hot air (e.g., its initial moisture content) is varied when the temperature of freshly dried tobacco particles deviates from a preselected temperature. This ensures that the moisture content of tobacco particles does not fluctuate subsequent to cooling which follows the drying operation.

Abstract: Apparatus wherein tobacco is dried in several successive units each of which contacts a continuous stream of tobacco with hot air. The moisture content of tobacco is measured between a preceding unit and the next-following unit, and the temperature of hot air which is supplied by the next-following unit is respectively increased and reduced when the monitored moisture content of tobacco respectively rises and decreases. The temperature of air which is admitted by the preceding unit is maintained at a constant value. The temperature of air which is supplied by the next-following unit is further influenced, when necessary, in dependency on measurement of such temperature and in dependency on differences between the final moisture content of tobacco and a preselected optimum moisture content. The detector which monitors the moisture content between the preceding and next-following units is built directly into the conveyor which transports the tobacco stream through the drying units.

Abstract: A continuous stream of tobacco leaves is equalized on the endless belt of a weighing device which receives an unequalized stream from a carded conveyor forming part of a tobacco feeding device. The belt is pivotable with an arm of the weighing device in response to changes in the weight of successive increments of tobacco thereon. Such changes in weight are ascertained by a potentiometer and signals denoting the weight are transmitted to a function generator by way of an adding circuit as well as to a multiplying circuit which further receives signals denoting the speed of successive increments on the belt. Signals which are transmitted by the multiplying circuit are used to regulate the speed of the belt so that the product of signals denoting the weight and of corresponding signals denoting the speed of successive increments of tobacco on the belt remains constant.

Abstract: A continuous stream of burley or greenleaf tobacco is transported through a first and thereupon through a second heating unit wherein the particles of tobacco are heated by ascending currents of hot air supplied at a pressure and rate such that the respective portions of the stream are fluidized. First and second detectors are provided to measure the temperature of tobacco downstream of the first and second heating units. Signals from the detectors are used to regulate the temperature of the respective air currents. The temperature of air current which is admitted into the second heating unit is further regulated in dependency on deviation of signals furnished by the detector behind the first heating unit from a reference signal denoting the desired temperature of once heated tobacco. The temperature of each current of hot air is further regulated in dependency on the monitored temperature of air which is about to enter the first and second heating units.