Gneuss, a family-owned supplier of innovative solutions for the plastics processing industry, has developed a new JUMP system installed directly downstream of the Gneuss Processing Unit (GPU), which has over the years proven itself on the reprocessing of bulky PET waste, such as post-consumer bottle flake and industrial waste from fibre and film manufacture.

The system, which has been developed in addition to MRS design optimisation last year, is said to ensure an accurate and controllable IV boost of the PET in the melt phase. The 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 company explains.

First processing stage

The first important processing stage includes melt decontamination, which takes place in the extruder. With its devolatilisation capacity, the MRS extruder can process PET waste with high residual moisture levels and/or contamination without the need for any pre-treatment of the waste, according to the manufacturer.

In the Multi Rotation (MRS) section of the extruder a huge polymer surface area and extremely rapid surface exchange rate under vacuum are designed to ensure that all these contaminants are reliably extracted. Solid contamination is extracted with the fully-automatic and process-constant Gneuss Rotary Melt Filtration System.

Second processing stage

During the second 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. 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 aims to avoid 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 or to a pelletising 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, the company reports.

Short delivery times

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.

www.gneuss.com