Appts. for classifying tobacco particles

摘要

Particles of fibrous material in a stream contg. a random mixt. of long and shorter particles, are classified, in appts. which includes a vibratory conveyor with an elongate trough. The mixt. is introduced at one end of the trough and the longer particles are removed from the other. A number of longitudinal depressions are formed in the bottom wall of the trough to align the particles. The bottom wall also has at least one transverse slot to permit removal of the shorter particles. - More specifically, a vibratory conveyor comprises three parallel troughs including an upper trough, a lower trough and a lateral trough. The conveyor is vibrated via leaf springs connected to a frame and eccentrics. A mixed stream of particles of tobacco is fed to the left-hand end of the trough. The bottom wall of the trough has sections, the major part having elongate channels. The longer particles of the mixture become aligned in these channels. Transverse to the channels are slots, pref. angled to the sides of the trough towards an opening in the trough sidewall connected with the lateral trough. Each slot is bounded by a downstream surface which is smooth and angled so that the slot widens in a downward direction. The upstream ends of the sections include smooth portions immediately downstream of slots. In use, the longer particles travel along the grooves to the outlet end. Shorter particles fall into the slots and most pass through to the lower trough from where they are delivered via apertures to a hopper. Other shorter particles are trapped by the surface and slide along to enter the lateral trough. This prevents blocking of the slots.