Extrusion International 5-2018

31 Extrusion International 5/2018 ing of bulky PET waste such as post-consumer bottle flake and industrial waste from fiber and film manufacture without pre-drying. A Gneuss Processing Unit consists of a Gneuss MRS extruder with its unmatched devolatiliza- tion and decontamination performance in combination with a highly-efficient Gneuss Rotary Filtration System and an online viscometer VIS for intelligent dynamic vis- cosity control. Although originally developed specifically for PET, the MRS is now also running in polyolefin and nylon appli- cations, and being tested on a range of other materials and applications. Thanks to the patented combination of single screw extruder with a multiple screw section, the extruder is very sturdy and particularly well suited for re- cycling applications. The MRS extruder permits the processing of PET without pre-drying by using a simple water ring vacuum system to process the material directly to high quality end prod- ucts. This is achieved by means of its unique and patented processing section. Based on a conventional single screw extruder, the Multi Rotation Section is a drum containing eight satellite single screws, driven by a ring gear and pin- ion transmission. The “barrels” cut into the drum are ap- proximately 30 % open and provide optimum exposure of the melt. Thanks to this design, the devolatilizing performance is approx. fifty times greater than that of a conventional single screw extruder – and this at a vacuum of only 25 to 40 mbar. By avoiding the need for a deep vacuum system and pre-drying, the MRS is an economically efficient alter- native to conventional technologies. Further arguments in its favor besides energy savings are the simple and rug- ged design, small footprint, its ease of operation and low maintenance, processing flexibility and last but not least its excellent melt quality and homogeneity. One area this technology has been especially successful is in PET sheet extrusion. Besides producing high quality rigid sheet, Gneuss now also offers the option for its PET sheet extrusion lines to quickly and flexibly switch to pro- ducing physically foamed PET sheet with the addition of Gneuss’ new PET foammodule. Foam sheet with a weight reduction of 50 % can be extruded (depending on the process) with a consistent foam structure and mechani- cal properties. And this from up to 100 % post-consumer material. Foamed PET sheet is an ideal material for eco- nomically manufacturing thermoformed containers for the food industry such as meat trays, egg cartons, cups or plates. Customer-focused sensor technology As a machinery manufacturer, Gneuss has the manu- facturing capabilities to realize even unusual sensor re- quirements. 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 Communica- tion or EAC. In especially difficult process conditions with short pressure overloads, frequent pressure spikes as well as unmelts in the material, sensors are highly stressed. Gneuss builds a special heavy-duty design with a special membrane technology for these applications. Also, Gneuss offers a special transducer for food applica- tions, where regular cleaning of the machinery is neces- sary, so that sensors are often subject to steam or water jets. Gneuss has developed a special type of sensor for these applications, which remains waterproof even if its plug is removed. Gneuss Kunststofftechnik GmbH www.gneuss.com Hall A6, Booth 6501 Sheet extrusion line with Multi Rotation Extruder MRS, Rotary Filtration System RSFgenius, and Online Viscometer VIS