Residence Time Distribution Curves of Screw Elements in Twin-Srew Extruder
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R. B. R. Calumby
Abstract
The additiveness of equivalent residence times method of deconvolution/convolution was used to determine the RTD curves of individual screw elements in the melt region of a twin-screw extruder. Initially RTD curves were obtained injecting a tracer (TiO2) at two different ports in the extruder barrel, using several screw configurations and operation conditions. Both ports are downstream, after the melt seal, well inside the molten polymer screw section. Then using the deconvolution method the RTD curve referent to the portion between the two ports was calculated. Finally, using again the deconvolution method and the data from several screw configurations the RTD of each individual screw element was obtained. The independence of screw element positions was also evaluated, where specially designed screws (e. g. changing the position and type of screw elements) were tested, showing no significant effect in the RTD curves. Kneading elements of 45 degrees (KB45) showed an important contribution of conveying, while kneading elements of 90 degrees (KB90) practically do not show any conveying, being characterized mainly by a pressure flow. With RTD curves of individual elements is possible, using the convolution method, predict the RTD curve of any screw configuration. Experimental measurements using screw configurations specially designed were used to check this analytical method. Finally it was applied to data published in the literature, obtained using other deconvolution methods and the results compared and discussed.
© 2002, Carl Hanser Verlag, Munich
Articles in the same Issue
- Editorial
- Touchstones of Polymer Processing
- Twin Screw Extrusion and Compounding
- Residence Time Distribution Curves of Screw Elements in Twin-Srew Extruder
- Rheological Effect of Zinc Surfactant on the TESPT-Silica Mixture in NR and S-SBR Compounds
- Optimization of Processing Conditions for Polymer Twin-Screw Extrusion
- Fibers and Film
- The Prediction of Sharkskin Instability Observed during Film Blowing
- Tensile Strength Characteristics of Polymer Melts
- Biaxially Oriented PP Films Using the Double Bubble Process
- Fiber and Film
- Crystallization and Orientation Development in Melt Spinning Isotactic PP of Varying Tacticity
- Extrusion Coating
- Extrusion Coating with Metallocene-Catalysed Polyethylenes
- Injection Molding
- Design Sensitivity Analysis Applied to Injection Molding for Optimization of Gate Location and Injection Pressure
- Three-dimensional Numerical Modeling of Co-injection Molding
- Residual Stress and Warpage Models for Complex Injection Molded Parts
- Blow Molding
- Investigation of Design Parameters and Novel Design of Petaloid PET Bottles
Articles in the same Issue
- Editorial
- Touchstones of Polymer Processing
- Twin Screw Extrusion and Compounding
- Residence Time Distribution Curves of Screw Elements in Twin-Srew Extruder
- Rheological Effect of Zinc Surfactant on the TESPT-Silica Mixture in NR and S-SBR Compounds
- Optimization of Processing Conditions for Polymer Twin-Screw Extrusion
- Fibers and Film
- The Prediction of Sharkskin Instability Observed during Film Blowing
- Tensile Strength Characteristics of Polymer Melts
- Biaxially Oriented PP Films Using the Double Bubble Process
- Fiber and Film
- Crystallization and Orientation Development in Melt Spinning Isotactic PP of Varying Tacticity
- Extrusion Coating
- Extrusion Coating with Metallocene-Catalysed Polyethylenes
- Injection Molding
- Design Sensitivity Analysis Applied to Injection Molding for Optimization of Gate Location and Injection Pressure
- Three-dimensional Numerical Modeling of Co-injection Molding
- Residual Stress and Warpage Models for Complex Injection Molded Parts
- Blow Molding
- Investigation of Design Parameters and Novel Design of Petaloid PET Bottles
