Flexible Miniature Compounder
A new 16 mm twin-screw extruder permits optimisation of processing parameters even when only small quantities of material are available, production of test specimens or performance of quality control inspections. The system can be matched to the task at hand with only a few modifications.
For extrusion and compounding of test quantities ranging in size from 50 g to 15 kg, Haake Elektron has developed a parallel twin-screw extruder with a screw diameter of 16 mm. With its large flight depth, the design assures problem-free feeding of pellets as well as powders having a low bulk density. The segmented screw construction with elements only 0.25 D in length offers a great deal of freedom for fine tuning to various processing tasks.
The modular extruder concept can be adapted to the desired application very quickly. The barrel is split horizontally. The upper half of the extruder barrel consists of 4-D modules that are fastened together via two (Zuganker). As a result, the feed, venting and compounding zones can be reconfigured quite easily.
The short processing length of 25 D permits processing of small test quantities, along with minimal cleaning time for product changes. An expansion module is available for reactive extrusion and separate metering of various components. In this way, the processing length of the extruder can be increased from 25 D to 40 D in a few simple steps.
The rheology module, which can be integrated directly into the compounding process to provide online rheological information on the current mixture, is especially interesting for twin-screw compounding. Such a rheology module consists of a melt pump, a rheological slit capillary, round capillary or extensional rheology die and the PolyCap capillary software OS. In addition to the determination of absolute viscosity curves, the software permits, for example, the calculation of Carreau factors that can be used for modelling of flow geometries.
The metering systems necessary for experiments are integrated into the modular PolyLab OS rheometer platform, just like the other measurement sensors. Thanks to the standardised CAN Open Bus and the USB interface, the system can be modified to meet individual application requirements quickly and easily. In addition to existing system components, modified sensors as well as customer-developed items can be incorporated.
Thermo Electron (Karlsruhe) GmbH
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