Elastomeric Extrusion Through Gear Pumps for Consistent Product Weight

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Solution Overview

Problem

Existing extrusion processes for elastomeric materials in tire production suffer from variability in flow rate and weight of the extruded semi-finished product due to changes in viscosity caused by temperature fluctuations and thermal inertia, leading to structural defects and inconsistent deposition on forming supports.

Innovation Solution

A method to control the inlet pressure of the gear pump based on the exit pressure to maintain a constant pressure difference, ensuring a consistent flow rate and weight of the extruded semi-finished product by adjusting the inlet pressure within a predetermined range to compensate for viscosity variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the extrusion process uses conventional pressure control without compensation, then the equipment operation is simple, but the flow rate and weight of the extruded product vary due to viscosity changes

Engineering Contradiction:
Improveflow rate consistencyVSAvoidpressure control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where the actual inlet pressure is continuously measured and compared with the target inlet pressure, and the discrepancy is used to adjust the screw rotational speed to maintain consistent flow rate despite viscosity variations

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces purely mechanical pressure control with a hybrid system that incorporates sensors and computational algorithms to dynamically adjust operational parameters based on real-time pressure measurements

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the inlet pressure is increased to maintain flow rate, then the flow rate consistency improves, but the risk of material degradation and equipment damage increases

Engineering Contradiction:
Improveflow rate stabilityVSAvoidmaterial degradation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent employs dynamic adjustment of screw rotational speed based on real-time pressure feedback, allowing the system to adapt to changing material properties and operating conditions without applying excessive or harmful pressures

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameter (screw rotational speed) dynamically in response to measured pressure conditions, optimizing the extrusion process to maintain flow rate while preventing material degradation through controlled pressure levels

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the extrusion speed is increased to improve productivity, then the output increases, but the viscosity variations and flow rate inconsistency worsen

Engineering Contradiction:
Improveextrusion outputVSAvoidweight consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The feedback control system continuously monitors inlet pressure and adjusts screw rotational speed to compensate for viscosity changes, enabling high-speed extrusion while maintaining consistent product weight and dimensions

Inventive Principle:
Principle #23Feedback

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 ensures a stable and repeatable extrusion process by maintaining a constant flow rate and weight of the semi-finished product, reducing defects and enhancing process reproducibility.

Implementation Method 1

a method to control the inlet pressure of the gear pump based on the exit pressure to maintain a constant pressure difference

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

an extrusion screw rotatably mounted inside the hollow body... moves the elastomeric material from the upstream end portion of the hollow body to a downstream end portion of the hollow body

Methodology Applied
Scientific EffectMechanical transport:

Implementation Method 3

changes in viscosity caused by temperature fluctuations

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4255713B1Method for extruding a semi-finished product made of elastomeric material
Publication Date: 2025.10.08 PIRELLI TYRE SPA
  • EP4255713B1 patent drawingFigure 1
  • EP4255713B1 patent drawingFigure 2A~2B
  • EP4255713B1 patent drawingFigure 3

AI summary

The invention relates to a method for extruding a semi-finished product made of elastomeric material, wherein an elastomeric material is fed to an inlet channel (20a) of a gear pump (20) with an inlet pressure value and dispensed through an exit channel (20b) of the gear pump (20) with an exit pressure value greater than the inlet pressure value. The method comprises detecting the exit pressure value and adjusting the operation of said gear pump (20) so as to maintain a predetermined pressure difference between said exit pressure and said inlet pressure based on the detection of the exit pressure value. The aforementioned method is used in a process for building a tyre for vehicle wheels.