To separate a plastic mixture composed of a plurality of kinds of plastic of low specific gravity and low specific gravity difference by each material quality to facilitate recycling.
The specific gravity separation device is constituted of a cylindrical section 3 with its axial line disposed almost vertically, a barrel 7 combined with a conical base section 6 with its large diameter end connected concentrically with the lower end of the cylindrical section 3 and the small diameter end disposed below, a cylindrical inserting pipe 8 disposed concentrically to the cylindrical section 3 in the barrel 7 and having its upper end protruded above the upper end face of the cylindrical section 3 and its lower end opened in the body, a feed section 2 connected with the upper outer periphery of the cylindrical section 3 in the tangential shape and feeding a mixture of materials of quality of different specific gravities into the body together with a specific gravity liquid, a horizontal section 5 so disposed as to block the small diameter end of the conical stand section 6 and forming a body bottom face, a tubular lower recovery opening 9 connected with an opening formed on the horizontal section 5 and extending downward and another lower recovery opening formed below. It that case, the flow rate of specific gravity liquid to be fed is adjusted so as to flow out easily water downward on the outermost periphery of an air column in a rising swirl flow formed in the inserting pipe 8.
HAYASHI MASAKATSU
AOKI MAKOTO
TAKAMURA YOSHIYUKI
HASEGAWA TSUTOMU
