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Title: Process engineering design of co-rotating twin screw extruders
Author: Schuler, Werner
ISNI:       0000 0004 2735 0422
Awarding Body: Swansea University
Current Institution: Swansea University
Date of Award: 1996
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The intention of the work was to develop easy to use technical design methods which are helpful for the daily work of the process engineer, and which also describe the operating behaviour of both the whole extruder and the individual processing sections. This goal was achieved by developing new models or the further developing of existing models. The examination of the developed models by trials and on production lines showed good accuracy of the models. The following models, which are developed in the present work, are of particular interest for the technical design of extruders: • Simple model for the calculation of the solids conveying capacity derived by trials. • Calculation of the melt transport in screw elements by simple models which are examined by test series with various extruder sizes, screw elements and polymers. • Design rules for screw elements used for melt discharge. • A model for the description of the degassing process was derived in terms of the operating equation of the degassing zone. The described operating equation shows a good agreement with degassing results obtained in various degassing trials. • Description of the operating behaviour of solid fed extruders and a simple assessment of the specific drive energy using the specific enthalpy rise. • Introduction of the mean shear stress at the barrel wall for melt fed co-rotating twin screw extruders and description of the operating behaviour by the operating equation. The influence of different feed temperatures and melt flow index values are also considered. • Scale-up for compounding and degassing tasks and the necessary restrictions to achieve the same results on test and production extruders. • Development of an analytical method for the design of extruder series by the optimal diameter ratio, dependent on whether the extruders are melt or solid fed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available