Gneuss: Innovative Technologies for Polymer Processing and Recycling
The Gneuss Processing Unit (GPU) has been available for several years now and has proven itself on the reprocessing of bulky PET waste such as post-consumer bottle flake and industrial waste from fibre and film manufacture.See product and contact details of Gneuß Kunststofftechnik GmbH.
This Gneuss Processing Unit consists of the Gneuss MRS extruder with its unmatched devolatilisation and decontamination performance together with the highly-efficient Gneuss Rotary Disc melt filtration systems and the Gneuss Online Viscometer for intelligent dynamic viscosity control, monitoring and logging.
Additionally to MRS design optimization since the last year, Gneuss has developed the new JUMP system. This is installed directly downstream of the Gneuss Processing Unit and thanks to its ingenious process ensures an accurate and controllable IV boost of the PET in the melt phase. The Jump system is a compact, quick and efficient alternative to conventional SSP (solid state) systems and enables direct reintroduction of the polymer into the production process without the need to remelt the PET.
With the Gneuss industrial waste concept, industrial waste is first fed through a shredder or a knife mill until the size is reduced so that it can be fed into the extruder. This can mean either compaction of the size reduced waste or a crammer feeder fitted directly to the extruder.
The first important processing stage: melt decontamination takes place in the extruder. With its enormous devolatilisation capacity, the MRS extruder can process PET waste with high residual moisture levels and/or contamination (such as spin finish oils) without the need for any pre-treatment of the waste. In the Multi Rotation (MRS) section of the extruder a huge polymer surface area and extremely rapid surface exchange rate under vacuum ensure that all these volatile contaminants are reliably extracted. Solid contamination is extracted with the fully-automatic and process-constant Gneuss Rotary Melt Filtration System. With filtration finenesses of down to 20 µm and below, a pure and particle – free polymer melt is guaranteed.
During the second important stage of the process, the purified and homogenised polymer is fed by means of a melt pump into the JUMP. Here, too a large surface area of the polymer melt and optimum residence time of the polymer under vacuum are decisive factors. Subsequently, the purified and homogenised polymer is fed by means of a melt pump into the JUMP, where the second important stage of the process takes place. Here, too a large surface area of the polymer melt and optimum residence time of the polymer under vacuum are decisive factors. The polymer melt is kept under vacuum as it passes over slowly rotating elements. Through control of the residence time and the speed of the rotating elements, controlled polycondensation takes place whereby controlled IV boosting takes place of typically 0,02 to maximum 0,3 dl/g. The design of the Jump system avoids the ingress of oxygen so that the yellowing effect encountered during the recycling of PET is reduced to an absolute minimum. After the PET melt has passed through a stilling chamber in the JUMP system, the polymer is pumped directly into the production process (for example direct extrusion spinning, strapping) or to a pelletising (chip cutting) system. With the complete system consisting of the Gneuss Processing Unit with the MRS Extruder and a JUMP system, industrial waste can be quickly and efficiently reprocessed in one processing step to a high quality polymer melt which can be directly processed to a finished product.
Gneuss Processing Unit (GPU) gives Sheet PET Lines increased Flexibility and Food Contact Certification
In the worldwide growth industry of PET packaging sheet, Gneuss has installed over 20 tailor-made sheet lines over the last few years. Gneuss´ customers find the extreme flexibility of the Gneuss Processing Unit (GPU), consisting of MRS extruder, Rotary Filtration System, Online Viscometer and Control System completely convincing when processing PET, whether virgin or recycled material and with or without food contact requirements.
Within the packaging industry, the use of PET sheet is on the increase and the use of recycled material is likewise on the increase. Whether the PET sheet is used for transparent packaging for food (trays or tubs for fruit, vegetables, meat, cookies etc.) or for non-food (such as blister packaging) it is always important to take account of the particular properties of PET and it is exactly this which Gneuss has done.
With the Multi Rotation System (MRS) Extruder, Gneuss has developed the only extruder specifically designed not only with the material PET in mind, but with the reprocessing of PET. With the MRS extruder Gneuss offers a processing unit which enables PET to be extruded cost effectively, without any pre-drying or crystallisation. This applies both to the processing of both virgin and post- consumer bottle flake with a residual moisture level of 1 % and in some cases more. The extruder will also easily handle PET / PE scrap (laminated sheet) and mixtures of PET and PETG. Thanks to the extremely high polymer surface exchange rate under vacuum in the MRS section, a vacuum level of only 25 bar is required in order to achieve 100 % moisture extraction. Another effect of the extremely high polymer surface area exchange rate under vacuum is the excellent extraction of volatile contaminants. The system achieves the requirements of the FDA, EFSA and Invima without restrictions. PET sheet made on the MRS extruder is therefore suitable for food contact applications whatever input material is used and without any pre-treatment of the input material.
The Gneuss Processing Unit includes also the unique Gneuss Rotary Melt Filtration System for the efficient removal of solid contaminants with fine filter elements even on post-consumer bottle flake. The Gneuss Online Viscometer ensures a consistent, defined IV value of the polymer thanks to the intelligent control system and is an extremely useful tool for quality monitoring and control.
Gneuss offers complete lines including the up- and downstream components from the material dosing system to the die, roller stack and to the winder, which are all tailored to the exact requirements of the individual customer.
The Gneuss GPU can also be used to produce foam sheet from PS or PET with up to 30% weight reduction and even higher depending on the application. The system is fully flexible and no mechanical changes are necessary when switching from transparent sheet to foam sheet production. Also the use of up to 100% PET Bottle flakes is possible in both applications.
Revision of process and pressure constant Rotary Filtration Systems for the widest range of different applications
Both the RSFgenius as well as the SFXmagnus ranges have been completely revised during 2016. Modifications to the screen changer housings permit operation on a wider range of applications at higher pressures, whilst offering enlarged active filtration areas. Components and modules have been commonised between the two ranges in order to offer even more attractive value for money and shorter delivery lead times.
The patented RSFgenius Filtration Systems operate fully-automatically, process and pressure-constant and with a back-flushing system with unmatched efficiency. They are therefore especially suitable for demanding applications with high quality requirements.
The SFXmagnus range of automatic screen changers is characterised by an extremely large active area in a compact unit. This range of screen changers is available with or without an integrated back-flushing piston depending on the exact requirements of the process.
New for PVC processing is the SFpvc R, a further development of the SFpvc. Both models are designed specifically for challenging PVC recycling applications but the new SFpvc R offers for the first time an integrated self-cleaning (back flushing) system whilst maintaining absolute process-constant operation.
Highest quality, short delivery times: even for individual, tailor-made sensors
Gneuss offers individually tailor- made melt pressure and melt temperature sensors even outside of the typical market standards. As a machinery manufacturer, Gneuss has the manufacturing capabilities to realise even unusual sensor requirements. The lean manufacturing structure at Gneuss makes this possible with shortest delivery times. Gneuss sensors are available to match regional or application – specific requirements such as Atex, Hart Communication or EAC.
The new DAIL melt pressure transducer range from Gneuss is a special addition to the range, specifically for pressure overload protection. Whether as an economic single sensor system for standard applications or a complete system solution for explosion hazard environments, Gneuss has a pressure monitoring system for every application.