PLASTIC SPECIFIC GRAVITY SELECTION DEVICE AND ITS METHOD

摘要

PURPOSE:To improve the fractionation efficiency of shredded pieces of waste plastic by selecting charged plastic pieces by specific gravity difference separation while the pieces are flowing through a water path. CONSTITUTION:Various kinds of waste plastic shredded to any appropriate size previously are charged into a water path under a water flow-adjusted condition from a hopper 11. Then bubbles sticking to the surface of the plastic are first removed by a stirrer 32. Further, coupling with a descending swirl generated by the stirrer 32, all plastic pieces flow along a flow path forming plate 52 regardless of their specific gravity higher or lower than the specific gravity of a water medium having an appropriate specific gravity for selecting a plastic mixture. In this way, the pieces which sink and float are selected utilizing plastic specific gravity difference or a water flow at a constant speed. The pieces having a high specific gravity is further selected using the flow to obtain finer pieces.