Method and apparatus for forming a filler of fibrous material

摘要

A continuous rod-like filler which is ready for draping into a web of cigarette paper is obtained by removing the surplus of tobacco from a continuous tobacco stream which is formed at one side of a foraminous belt conveyor the other side of which is adjacent to a suction chamber serving to attract the particles of tobacco to the conveyor. The surplus is removed downstream of the zone where the particles of tobacco are delivered to the conveyor. The density of the filler is monitored subsequent to draping, and the signals which are generated by the density monitoring device are used to vary the pressure in the suction chamber, to vary the speed of a first rotary conveyor which propels particles of tobacco against the belt conveyor and/or to vary the rate of feed of tobacco particles to the belt conveyor by adjusting the speed of a second rotary conveyor which draws tobacco particles from the lower end of a duct. Each of the above adjustments is effective to change the density of the filler so that the changed density matches or more closely approximates an optimum value. The plane in which the surplus is removed from the tobacco stream is maintained at a constant distance from the belt conveyor.