Planetary Roller Extruder Central Spindle Speed Increase

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Solution Overview

Problem

Planetary roller extruders face challenges in asserting themselves over single-screw and twin-screw extruders due to their complexity and lower operational speeds, which limit their efficiency in processes like plasticizing, homogenizing, and cooling, especially in larger sizes where speeds are significantly lower.

Innovation Solution

Increasing the speed of the central spindle in planetary roller extruders by multiplying usual speeds up to 6 times, while using torque motors for high-pole electric direct drives to maintain mechanical integrity and efficiency, and ensuring minimum filling levels to prevent damage and malfunctions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the speed of the central spindle is increased to improve processing efficiency and dispersion, then productivity and mixing quality improve, but the risk of damage and malfunction increases due to higher loads on planetary spindles

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidrisk of damage and malfunction
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by increasing the rotational speed of the central spindle by a factor of 2 to 6 times compared to conventional speeds. This parameter modification directly improves productivity and dispersion quality while the patent addresses the resulting increased loads through corresponding structural adaptations in the planetary spindle design and support system

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by transitioning from static, low-speed operation to dynamic, high-speed operation of the central spindle. The system is designed to operate at elevated speeds with improved dispersion effects, while dynamic load management is achieved through the bearing arrangement and support structures that accommodate the varying loads at higher rotational speeds

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If planetary roller extruders are designed with complex structures to achieve intensive mixing and homogenization, then processing quality improves, but device complexity increases making them less competitive against single-screw and twin-screw extruders

Engineering Contradiction:
Improvehomogenization qualityVSAvoidstructural complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the extruder into distinct functional sections: a planetary roller extruder section for intensive mixing and homogenization, and single-screw extruder sections for material intake and discharge. This modular segmentation allows each section to perform its specific function optimally while reducing the overall complexity compared to a fully planetary design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements universality by creating a hybrid extruder system that combines the advantages of different extruder types. The planetary section provides intensive mixing for specific processing requirements, while the single-screw sections handle material feeding and discharge, making the system versatile for various processing tasks without requiring the entire system to be overly complex

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If the number of planetary spindles is increased to improve mixing intensity, then homogenization improves, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvedispersion qualityVSAvoidnumber of components
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by optimizing the rotational speed of the central spindle as the key parameter for achieving improved dispersion and homogenization. Instead of increasing the number of planetary spindles, the patent achieves better mixing quality through elevated rotational speeds, thereby maintaining a simpler structure with fewer components while still attaining superior mixing performance

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This speed increase enhances the dispersion of mixture components, improves processing efficiency in the plastics and chemical industries, and allows for more effective distribution of reactants and additives, without significantly increasing the risk of damage or malfunction, even at higher loads.

Implementation Method 1

The insert mixture is processed in an extreme manner between the central spindle, the planetary spindles and the bushing. The processing is intensive because the extrusion material is rolled thinly and repeatedly between the planetary roller extruder parts

Methodology Applied
Scientific EffectMechanical rolling and shearing: Shear Stress

Implementation Method 2

torque motors for high-pole electric direct drives

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP2841250B1Operation of an extrusion line with a planetary roller extruder
Publication Date: 2019.09.18 ENTEX RUST & MITSCHKE GMBH
  • EP2841250B1 patent drawingFigure 1
  • EP2841250B1 patent drawingFigure 2

AI summary

On an extrusion system with a planetary roller extruder or planetary roller extruder section or planetary roller extruder module (22, 23, 24), the rotational speed of the central spindle is increased according to the invention by several times the otherwise known maximum rotational speeds, in order to achieve a fine dispersion.