Separation of dry material from e.g. mixed plastic waste shreddings or granules, involves using a slanted vibro-classifier screen supporting fluidized bed for air classification

摘要

Airflow through classifier surface, from and/or to a blower, is controlled and made uniform. Distributor (3) apportions and spreads material over full width of classifier screen (10) from vibratory conveyor (2). To prevent local reductions in airflow, part of airflow passes through distributor. Separated heavy material is removed from screen upper end and light material is taken from lower end. Material is extracted through air locks. An Independent claim is included for the corresponding separator. Preferred features: Air is forced up through the screen as well as being extracted from above, extraction and supply blowers being so matched that a steady state obtains, with desired pressure differential in the classification volume. Light and/or heavy fractions are further separated, the separate unit employed being adjusted for desired light and heavy fraction ratios. Salient features of the equipment include automatic screen tensioners for the perforated or woven metal surface at the base of the classifier. A system of ball packings and partitions under the screen, is detailed and quantified in terms of material density and sizes. Air locks (18, 19) are provided on each side.