Design of Dispersive Mixing Devices
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C. Rauwendaal
Abstract
Mixing is one of the main functions of screw extruders. In the analysis of mixing, there are two mixing mechanisms that need to be considered: distributive and dispersive mixing. It is well known that single screw extruders generally have poor dispersive mixing capability, even when dispersive mixing elements are incorporated into the screw design. This paper will discuss the requirements for dispersive mixing, current dispersive mixing elements used in single screw extruders will be analyzed, and the lack of efficient dispersive mixing will be explained. A new generation of dispersive mixing elements will be introduced for use in both single and twin screw extruders and internal mixers. A two and three dimensional flow simulation will be used to analyze the mixing performance of these new mixers. Experimental work on the new mixing elements will be presented in a follow-up paper; the results demonstrate that it is possible to achieve dispersive mixing on single screw extruders that is as good as what can be achieved on twin screw extruders. The implications of these results on the compounding industry will be briefly discussed.
© 1999, Carl Hanser Verlag, Munich
Articles in the same Issue
- Regular Contributed Articles
- Polymer Processing Problems from Non-Rheological Causes1
- Utilization of Rheology Control to Develop Wood-Grain Patterned PVC/Wood Flour Composites
- Screw Drive Power of Single Screw Plasticating Units With Smooth Barrels
- Design of Dispersive Mixing Devices
- Dynamic Performance of Single-Screws of Different Configurations
- A Comparative Study of Residence Time Distributions in a Kneader, Continuous Mixer, and Modular Intermeshing Co-Rotating and Counter-Rotating Twin Screw Extruders
- Influence of a ‘Rotating Tip’ on the Properties of Tubing Made Using a Cross-Head Tubing Die
- Modelling of Capillary Rheometer Data and Extrapolation of the Viscosity Function into the Linear Viscoelastic Region
- Relationship Between Structure and Spinning Processing of As-Spun PP Fibres
- Rheological and Theoretical Estimation of the Spinnability of Polyolefines
- Drawing of β-Crystal Nucleator-Added PP
- Wave Behavior in the Coating Process of Multilayer Polymeric Materials
- Process Optimization of Thermoforming PP/CaCO3 Composites
- A Stiffness Criterion For Cooling Time Estimation
Articles in the same Issue
- Regular Contributed Articles
- Polymer Processing Problems from Non-Rheological Causes1
- Utilization of Rheology Control to Develop Wood-Grain Patterned PVC/Wood Flour Composites
- Screw Drive Power of Single Screw Plasticating Units With Smooth Barrels
- Design of Dispersive Mixing Devices
- Dynamic Performance of Single-Screws of Different Configurations
- A Comparative Study of Residence Time Distributions in a Kneader, Continuous Mixer, and Modular Intermeshing Co-Rotating and Counter-Rotating Twin Screw Extruders
- Influence of a ‘Rotating Tip’ on the Properties of Tubing Made Using a Cross-Head Tubing Die
- Modelling of Capillary Rheometer Data and Extrapolation of the Viscosity Function into the Linear Viscoelastic Region
- Relationship Between Structure and Spinning Processing of As-Spun PP Fibres
- Rheological and Theoretical Estimation of the Spinnability of Polyolefines
- Drawing of β-Crystal Nucleator-Added PP
- Wave Behavior in the Coating Process of Multilayer Polymeric Materials
- Process Optimization of Thermoforming PP/CaCO3 Composites
- A Stiffness Criterion For Cooling Time Estimation
