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 method of and an apparatus for accurately measuring the moisture content of a moving bed of a product, such as strip tobacco, are disclosed. As the bed of tobacco is conveyed by a perforated or porous conveyor, a flow of air is directed upwardly through the conveyor and into the bed of tobacco. The air flow agitates and homogenizes the tobacco to provide a localized area of the bed of tobacco that has a substantially uniform moisture content from top to bottom. A moisture sensor located downstream of the air flow measures the moisture content of the agitated portion of the tobacco bed.
A method and apparatus for reordering hot, dry expanded tobacco comprises a first reordering step in which the tobacco moisture content is raised to a first value, an intermediate cooling stage in which the tobacco is cooled to about ambient temperature (20.degree.-25.degree. C.) followed by a final reordering step in which the tobacco moisture content is raised to a final desired value.
Cigarettes are formed from tobacco filler which is at a temperature in excess of approximately 35.degree. Celsius and having an elevated moisture content. For example, particles of tobacco filler having an elevated moisture content of approximately 13.5% to approximately 17% are heated by being exposed to a source of heat having a temperature of between approximately 35.degree. and approximately 60.degree. Celsius before being formed into tobacco rods. Preferably a temperature range of between approximately 43.degree. and approximately 52.degree. Celsius is employed. The heating source can be selected from infrared radiation sources, hot water jackets, heating coils, microwave radiation sources or air heated by any one or more of the foregoing. The heating process can take place during the acceleration of the tobacco filler particles from the distributor up to the permeable rod conveyor belt or from the tobacco feeding system supplying the distributor.
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.
