URBANREC

The GneussProcessing Unit (GPU) has been available for several years now and has provenitself for the reprocessing of bulky PET waste such as post-consumer bottleflake and industrial waste from fiber and film manufacture without pre-drying.A Gneuss Processing Unit consists of a Gneuss MRS extruder with its unmatcheddevolatilization and decontamination performance in combination with ahighly-efficient Gneuss Rotary Filtration System and an online viscometer VISfor intelligent dynamic viscosity control.

Althoughoriginally developed specifically for PET, the MRS is now also running inpolyolefin and nylon applications, and being tested on a range of othermaterials and applications. Thanks to the patented combination of single screwextruder with a multiple screw section, the extruder is very sturdy andparticularly well suited for recycling applications. The MRS extruder permitsthe processing of PET without pre-drying by using a simple water ring vacuumsystem to process the material directly to high quality end products. This isachieved by means of its unique and patented processing section. Based on aconventional single screw extruder, the Multi Rotation Section is a drumcontaining eight satellite single screws, driven by a ring gear and pinion transmission.The “barrels” cut into the drum are approximately 30 % open and provide optimumexposure of the melt.

Thanks tothis design, the devolatilizing performance is approx. fifty times greater thanthat of a conventional single screw extruder - and this at a vacuum of only 25to 40 mbar. By avoiding the need for a deep vacuum system and pre-drying, theMRS is an economically efficient alternative to conventional technologies.Further arguments in its favour besides energy savings are the simple andrugged design, small footprint, its ease of operation and low maintenance,processing flexibility and last but not least its excellent melt quality andhomogeneity.

One areathis technology has been especially successful is in PET sheet extrusion. Besidesproducing high quality rigid sheet, Gneuss now also offers the option for itsPET sheet extrusion lines to quickly and flexibly switch to producingphysically foamed PET sheet with the addition of Gneuss’ new PET foam module.Foam sheet with a weight reduction of 50 % can be extruded (depending on theprocess) with a consistent foam structure and mechanical properties. And thisfrom up to 100 % post-consumer material. Foamed PET sheet is an ideal materialfor economically manufacturing thermoformed containers for the food industrysuch as meat trays, egg cartons, cups or plates.

Thepatented Rotary Filtration Systems are characterized by the filter disk onwhich the screen cavities are located in a ring pattern and which is completelyencapsulated by the two filter blocks. Screens can be inserted into thecavities by opening a small hatch door giving access to the cavities while theproduction process continues to run without any interruptions or disturbances. Allmodels have been completely revised in the last years. Modifications to thescreen changer housings permit operation on a wider range of applications athigher pressures, whilst offering enlarged active filtration areas. Componentsand modules have been commonised in order to offer shorter delivery lead timesand lower costs.

TheSFXmagnus series operates automatically as well as process and pressureconstant. It is suitable for a very wide range of applications. This series ischaracterized by an extra large active screen surface area, its compact design,as well as extremely easy operation. Screen changes do not have any influenceon the product quality. Gneuss’ top model, the RSFgenius, operates with anintegrated self cleaning system for very demanding applications and highestquality requirements. Screens can be automatically re-used up to 400 times andfiltration finenesses below 10 microns/1200 mesh are available. The KF range ofcontinuous filtration systems is designed specifically for applications withfrequent material type, grade or color changes as well as for high pressureapplications like blown film. The KF screen changers are especially compact andoffer excellent value for money while permitting simple and quick screenchanges on the fly.

As amachinery manufacturer, Gneuss has the manufacturing capabilities to realizeeven unusual sensor requirements. The lean manufacturing structure at Gneussmakes this possible with shortest delivery times. Gneuss sensors are availableto match regional or application - specific requirements such as Atex, HartCommunication or EAC. In especially difficult process conditions with shortpressure overloads, frequent pressure spikes as well as unmelts in thematerial, sensors are highly stressed. Gneuss builds a special heavy-dutydesign with a special membrane technology for these applications. Also, Gneussoffers a special transducer for food applications, where regular cleaning ofthe machinery is necessary, so that sensors are often subject to steam or waterjets. Gneuss has developed a special type of sensor for these applications,which remains waterproof even if its plug is removed.

» More Information

« Go to Technological Watch