Method and apparatus for washing plastics materials

Abstract

Method for washing a plastics material (P) and for separating contaminating substances (C) therefrom comprises the steps of: supplying a first flow (FIN) of a washing fluid (W) together with the plastics material (P) with contaminants (C) to a washing container (2) in which a stirrer (3) generates a turbulent action to detach mechanically the contaminants (C) adhering to the plastics material (P),enabling a first fraction (X1) of heavier contaminants (C) to precipitate onto a first bottom portion (4) of the container (2), thus performing a first action of separating contaminants (C); transferring a second flow (F2) of fluid (W) with floating plastics material (P) from the container (2) to a first separating chamber (5), in which a second separating action takes place with the precipitation of a second fraction (X2) of the contaminants (C) onto a second bottom portion (6) of the first chamber (5); conveying a third flow (F3) of fluid (W) with floating plastics material (P) from the first chamber (5) to a second separating chamber (7) and evacuating by overflowing an outgoing flow (Fout) of fluid (W) together with the processed plastics material (P'); in the transit from the first chamber (5) to the second chamber (7) the agglomerates of floating plastics (P) are disaggregated, and to the third flow (F3) and to the plastics material (P) a downward propelling action (T) inside the second chamber (7) is imparted to promote a third separating action with precipitation of a third fraction (X3) of the contaminants (C) onto a third bottom portion (8) of the second chamber (7); removing from the second chamber (7) a recirculation flow (FR) comprising precipitated fluid (W) and contaminants (C) and sending the recirculation flow (FR) to a screen unit (US) that retains the contaminants (C), returning the washing fluid (W) to the first (5) or second chamber (7). The apparatus for implementing the aforesaid method is also disclosed.

Description

technical field [0001] The present invention relates to a method and a device for cleaning and separating plastic material from various types of pollutants from domestic and / or industrial waste, which is ground or reduced to pieces. Plastic fragments to be processed can come from eg containers, bottles, films and other post-consumer objects, and once they are decontaminated they can be reused as recycled material. [0002] Contaminants to be removed can include dirt, sand, gravel, various types of dirt, tags or other material elements still attached to the plastic fragments. Background technique [0003] In the field of processing recycled plastic materials, cleaning systems are known that provide one or more cleaning tanks or containers in which the material is transferred together with the contaminants to be removed that have accumulated on the material. [0004] From IT1326462 is known a device configured for continuous washing of recycled material previously reduced to ...

AI Technical Summary

Problems solved by technology

[0011] Unfortunately, in practice, cases have arisen that adversely affect the gravitational selection principle, greatly reducing the efficiency of the entire separation process

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