The particles of a continuous tobacco stream are conditioned during transport through a vibratory conveyor having a bottom wall located above a stationary chamber which receives conditioned air from one or more blowers. The bottom wall is formed with apertures through which the air passes across the tobacco stream in the form of pulsating currents which agitate the particles of the stream to insure a pronounced energy exchange between tobacco particles and air. The currents pulsate due to vibration of the bottom wall relative to the chamber, and the latter is provided with transversely extending baffles which insure that the tobacco stream is traversed by air currents having different intensities. The same result can be achieved by forming the bottom wall with larger and smaller apertures. The vibratory conveyor has two sections in the first of which the particles of tobacco are contracted by air having a temperature and moisture content corresponding to the desired temperature and moisture content of conditioned tobacco. The air which has been used for heating of tobacco in the first conveyor section is intercepted and is thereupon conditioned prior to admission into the second conveyor section.
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.
The disclosure is of improved apparatus and a method for producing tobacco rod from cut tobacco filler. The apparatus and the method include the use of a fluid bed of the tobacco particles to convey the tobacco particles from a source to the rod making machine.
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.
Apparatus for puffing, drying or moisturizing tobacco has a conveyor defining an elongated channel with an inlet and an outlet for particles of tobacco. The conveyor is vibrated so that the particles advance toward the outlet, and the bottom wall of the conveyor has orifices which serve to discharge jets of hot air or steam into the channel in such orientation that the jets of admitted fluid medium are inclined to each other, to the direction of advancement of tobacco particles and/or to the vertical. The orifices receive fluid from a chamber which is provided beneath the bottom wall and is connected to a source of steam or hot air. An advantage of the apparatus is that the exchange of heat and/or moisture between tobacco particles and the fluid is highly satisfactory, as well as that substances which are propelled by jets of fluid toward the top wall of the conveyor are more or less uniformly distributed along the entire top wall so that they are less likely to gather into large cakes which could become separated from the top wall to enter the flow of tobacco particles and to advance therewith to the next processing station. The bottom wall of the conveyor can have an undulate shape with the orifices provided in the flanks of hills which alternate with the valleys of such bottom wall.
Fragments of tobacco ribs are puffed in an elongated tunnel which is vibrated to advance the particles from the inlet toward the outlet. The particles in the tunnel are contacted by streamlets of supersaturated or superheated steam at such temperature and pressure that the temperature of the particles is raised to between 100.5.degree. and 120.degree. C. To this end, steam is admitted at 2.5 to 25 bar absolute pressure and at a temperature of between 126.degree. and 400.degree. C. The thus heated particles of tobacco ribs are thereupon dried.
