Compact Pelletizing Line for Post Consumer Materials

1.Ideal material preparation in the PreConditioning Unit
Cutting, homogenising, heating, drying, compacting, buffering and dosing – in a single stage. The dynamically controlled PreConditioning Unit is multitalented. It prepares the plastic ideally for the extruder and sets the
course for consistently high end product quality already at the beginning of the recycling process.

2.Gentle melting with low shear stress
Thanks to the preconditioning unit the extruder is fed warm material instead of cold. The advantage over conventional sys- tems: a relatively short extruder screw is enough to melt the already dry and thoroughly warmed material. The shear stress
extremely low as a result while the melt quality is high

3. Fine filtration
High-performance filtration: Part 1
Efficient filtering is one of the central strengths of the Compact. Thanks to the gentle preparation in advance, the Polyretec high-performance Laserfilter has an easy time. That is because dirt particles and impurities such as paper (e.g. from labels), fragments of wood (e.g. from pallets) and foreign polymers are hardly reduced in size before hand and are there- fore large enough for them to be easily removed from the melt. Thanks to the ingenious design of the Laserfilter scraper geometry, contaminants are lifted particularly quickly and continuously – and thus filtered even more effectively.

4.Perfect homogenisation of the melt
The final homogenisation of the melt in the Plus Zone of the extruder, i.e. downstream of the first filtration unit and upstream of degassing, enhances the subsequent degassing performance and improves the characteristics of the melt.

5.Even stronger degassing performance
The Compact features impressive, high-performance degassing. This takes place very effectively in three stages: initial degassing already occurs in the preconditioning unit. Step two is reverse extruder degassing – made possible through optimised screw design. The final double venting degassing at the extruder is particularly effective and removes gas inclusions which are still present from the melt.

6.Melt pump for temperature reduced pressure build up
Because there is no discharge metering zone and the melt pump is custom designed to the application, the pressure build-up required for the second filtration unit is highly efficient and needs a much lower temperature*. The extruder therefore does not need to build up pressure and can be much shorter (minus 10 L/D compared to the previous EREMA double filtration solution). Another advantage of the melt pump handling pressure build-up is that the extruder speed can be optimally matched to the polymer - without compromising on throughput
The lower melt temperature of the DuaFil® Compact in this area significantly reduces energy consumption. That has a positive effect on the quality of the melt. This is reflect- ed in the lower tendency to develop unpleasant odours or discolouration, which is much higher in systems that op- erate at higher temperatures. This is a real quality bonus, especially in applications involving cellulose-based materials such as paper or wood - like in supermarket film recycling, for example.
Only pre-filtered and degassed melt in melt pump
Another bonus of the plant design is the particularly advan- tageous location of the melt pump in the TVEplus® process sequence: filtration > degassing > melt pump. This means that only cleaned and degassed melt flows through the melt pump – an advantage for the service life of this component.

7.Final fine filtration
High-performance filtration:
In the second filtration unit, the already degassed plastic melt is filtered again at the ideal pressure, which is built up by the energy-saving melt pump. This additional filtration step significantly raises the quality level of the recycled pellets.
the filtration fineness of the second filter can now be particularly fine - even finer than the first filter, depending on the application. This supports further processing into end products of particularly high quality.