Extrusion International 5-2017

43 Extrusion International 5/2017 tion with granulators and made many further im- provements to recycling techniques using state of the art equipment. Worthless dust becomes valuable raw material Many manufacturing processes produce dust and fines, which are separated from the production pro- cess and are looking for a reclamation. Here some examples: - Textile flock in textile finishing - Fines when recycling post-consumer PET bottles, arising with friction washers and centrifugal dryers - Fluffs arising during the recycling of bottle crates which are separated by air separation after size re- duction - Textiles or fibres arising when separating com- pound materials, e.g. the recycling of used tires Up to now many of these materials ended up in com- bustion, but this is not ideal due to thehigh calorific val- ue that might damage the waste incineration plants. HERBOLD Meckesheim has a different approach to solving the problem: the material is slightly compact- ed in the HERBOLD Plastcompactor and transformed into agglomerate with a high bulk density and with excellent flow properties. The material is processed in continuous operation, between a fixed and a ro- tating disc, equipped with replaceable kneading bars. The pre-granulated material is conveyed con- tinuously from the buffer silo by means of a continu- ously adjustable feeding screw into the processing zone through the center of the fixed disc. Due to the friction on and between the compacting discs, the amount of friction is determined by the distance be- tween discs which is adjustable, the material is heat- ed quickly, spun off and conveyed via a central down- streamblower to the secondary granulator. Since the dwell time of the material in the compacting zone is only a matter of seconds, the thermal impact on the material is minimal contrary to extruders. Herbold Meckesheim’s developments are ground- breaking. Herbold has developed wet size-reduc- Herbold Meckesheim GmbH www.herbold.com Hall A6, booth 6511 Fig. 2: Base body with exchangeable wear parts Fig. 3: PET dust before and after compacting in a Herbold Plastcompactor