Abstract: There is provided an apparatus which can simplify, expedite and enhance the segregation of undesirable particles from desirable particles in a multiple-layer flow wherein the desirable and undesirable particles are randomly intermixed with each other. This is accomplished by a stepwise reduction of the thickness of the flow to thus locate all or nearly all undesirable particles at or close to the exposed sides of the resulting relatively thin flow so that the undesirable particles can be readily detected and segregated from the thin flow.

Abstract: An apparatus for manipulating a multilayer stream of tobacco particles with randomly intermixed foreign particles has a vibratory conveyor which advances the stream toward and discharges successive increments of the stream onto the upper reach of an endless belt or chain serving to advance the increments at a speed exceeding the speed of advancement of the stream by the vibratory conveyor. The endless belt or chain discharges a single layer of tobaco particles and foreign particles, and such single layer is caused to move past a segregating unit which detects and expels foreign particles therefrom.

Abstract: A hygroscopic commodity, such as a continuous stream of shredded tobacco, is transported past one or more sources of electrical energy and past one or more monitoring devices. One of the sources can expose the stream to the electric field of a capacitor in a high frequency oscillator circuit, and the other source can expose the stream to infrared waves or microwaves. The moisture in the stream influences the phase and/or the damping of oscillations of the electrical energy, and the monitoring device of devices ascertain the changes of such characteristics of the electrical energy and transmit corresponding signals to a processing circuit which processes the signals into moisture signals.

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.