Mixing Extruder Suction for Elastomeric Compound Fluid Removal

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Solution Overview

Problem

Existing tire production methods using continuous mixers for elastomeric compounds face inefficiencies in fluid removal at low suction pressures, leading to sudden changes in workability and mechanical features of the compounds, affecting tire performance.

Innovation Solution

Implementing a method with a multi-screw mixing extruder that includes suction at specific points during the mastication and transport steps, using high vacuum suction to efficiently remove undesirable fluids, and employing a silica-based filler with silane coupling agents to enhance compound properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If continuous mixers are used for producing elastomeric compounds, then productivity is improved, but fluid removal efficiency deteriorates at low suction pressures

Engineering Contradiction:
Improvecontinuous mixing productivityVSAvoidfluid removal efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing suction pressure within the range of 50-500 mbar to achieve efficient fluid removal while maintaining continuous mixing productivity. This parameter optimization resolves the contradiction by finding the optimal pressure window where both continuous operation and effective fluid evacuation are achieved.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements preliminary action by providing vent openings in the extruder body before the material exits, allowing fluids to be removed during the mixing process itself. This preliminary fluid removal prevents sudden property changes and maintains compound consistency throughout continuous production.

Inventive Principle:
Principle #10Preliminary action

2Object-generated harmful factors

If suction pressure is kept low for fluid removal, then harmful factor removal is improved, but compound workability and mechanical features change suddenly

Engineering Contradiction:
Improvefluid content in compoundVSAvoidcompound workability and mechanical features
Core Design Contradiction:
Object-generated harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent resolves this contradiction by defining a specific suction pressure range (50-500 mbar) that balances fluid removal with composition stability. Within this optimized parameter window, harmful fluids are effectively evacuated while sudden changes in compound properties are prevented, maintaining consistent workability and mechanical features.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback control by monitoring compound properties and adjusting suction pressure accordingly. This ensures that fluid removal is optimized while preventing excessive pressure drops that would cause sudden changes in compound characteristics, thereby maintaining stable composition throughout the process.

Inventive Principle:
Principle #23Feedback

3Loss of substance

If vent openings are provided in extruder body, then fluid removal is improved, but device complexity increases

Engineering Contradiction:
Improvefluid removal from compoundVSAvoidextruder structure
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent applies segmentation by distributing multiple vent openings at different locations along the extruder body. This segmentation allows progressive fluid removal at different stages of the mixing process, achieving thorough fluid evacuation while maintaining a relatively simple overall device structure through modular placement of vent holes.

Inventive Principle:
Principle #1Segmentation

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 approach improves the processability and mechanical properties of the elastomeric compounds, resulting in enhanced tire performance and consistency across a range of suction pressures.

Implementation Method 1

at least one suction pump (24) for removing fluids from said compound precursor or from said compound

Methodology Applied
Scientific EffectVacuum suction: Vacuum

Implementation Method 2

work at pressure values little lower than the atmospheric pressure

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 3

employing a silica-based filler with silane coupling agents to enhance compound properties

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentEP2655029B1Method for producing tyres
Publication Date: 2017.08.02 PIRELLI TYRE SPA
  • EP2655029B1 patent drawingFigure 1
  • EP2655029B1 patent drawingFigure 2~3
  • EP2655029B1 patent drawingFigure 4

AI summary

The present invention relates to a method and an apparatus for producing tyres. The apparatus comprises a mixing extruder (1) including a suction pump (24) in fluid connection with an inner chamber (17) of the mixing extruder (1) at a sector of the mixing extruder (1) close to an extruder head (19), such a suction pump (24) being suitable to operate at a suction pressure (Pa) preferably lower than about 150 mbars. This suction pressure enables the processing ability features of the elastomeric compound, as well as the performances findable in a tyre obtained from semimanufactured products produced with said elastomeric compound, to be improved.