Abstract: Tobacco shreds which are conveyed from a source in the form of a continuous stream are mixed with expanded tobacco ribs in such a way that the ratio of dry weights of successive unit lengths of the two streams which reach a mixing station remains constant. To this end, the moisture content of successive unit lengths of the two streams is measured by discrete detectors, and the overall weight of successive unit lengths of the stream of tobacco shreds is determined by a weighing device. A first analog computer is connected with the moisture detector for tobacco shreds and with the weighing device and transmits signals which are indicative of the dry weight of successive unit lengths of the stream of shreds. A ratio selector circuit determines the required dry weight of successive unit lengths of the rib stream in response to signals from the first computer and transmits such signals to a second analog computer which is further connected with the moisture detector for the rib stream.

Abstract: Moist tobacco is conveyed through a rotating drum which is heated by steam circulating coils and wherein a current of hot air is caused to flow counter to the direction of tobacco transport. The moisture content of conditioned tobacco is monitored by a detector which produces a first signal when the monitored moisture content deviates from a desired moisture content. The first signal is used to rapidly change the temperature of the air current from a standard temperature by adjusting the position of a valve which mixes hot air with cooler air whereby the extent of adjustment corresponds to the extent of deviation of monitored moisture content from desired moisture content. A second signal whose intensity is indicative of the extent of valve adjustment is transmitted to the input of a proportional-plus-integral amplifier which immediately changes the steam pressure in the coils and additionally changes the steam pressure while the temperature of the hot air current deviates from the standard temperature.