Co-extruded Electrofusion Strip for Uniform Plastic Pipe Welding

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Solution Overview

Problem

Existing electrofusion bands for welding plastic pipelines require high electrical voltage and long welding times, especially for large pipe diameters, leading to safety concerns, increased costs, and non-uniform heating, necessitating diameter-specific parts and complex geometry.

Innovation Solution

The electrofusion strip consists of a co-extruded jacket and heating element, with high-conductivity contact elements, allowing for low voltage welding and homogeneous heating, enabling universal use across various pipe diameters with reduced production costs and flexible assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a welding wire is used to heat the electrofusion band, then the structure is simple, but the electrical voltage required increases sharply for large pipe dimensions

Engineering Contradiction:
ImprovestructureVSAvoidelectrical voltage
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical heating method (welding wire) with an electrically conductive plastic heating element that can be integrated into the electrofusion band structure. This substitution allows for more efficient electrical energy distribution and reduces the voltage requirement while maintaining heating effectiveness across different pipe dimensions.

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

Solution Approach 2:

The patent uses composite materials, specifically electrically conductive plastic, to create a heating element that is integrated into the electrofusion band. This composite material approach allows the heating element to be formed as a continuous band with the jacket, enabling homogeneous heating and reducing the electrical voltage required compared to separate wire heating systems.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If a welding wire is used to heat the electrofusion band, then the structure is simple, but the welding times are greatly increased

Engineering Contradiction:
ImprovestructureVSAvoidwelding time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical heating method (welding wire) with an electrically conductive plastic heating element that provides more efficient and uniform heat distribution. This substitution significantly reduces welding times while maintaining the structural simplicity of the electrofusion band through integrated manufacturing.

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

Solution Approach 2:

The patent changes the heating parameters by using an electrically conductive plastic with optimized electrical and thermal properties. This allows for controlled heat generation that melts the fusion zone more efficiently, reducing welding times from several minutes to just seconds while maintaining bond strength.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a welding wire is used to heat the electrofusion band, then the structure is simple, but the heating is not homogeneous

Engineering Contradiction:
ImprovestructureVSAvoidheating uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent uses composite materials, specifically electrically conductive plastic, to create a heating element that is integrated into the electrofusion band. This composite material approach allows the heating element to be formed as a continuous band with the jacket, enabling homogeneous heating across the entire welding surface.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent merges the heating element and the jacket into a single co-extruded component. This integration ensures that the heating element is uniformly distributed throughout the electrofusion band, providing homogeneous heating across the entire welding surface and eliminating the non-uniform heating problems associated with separate wire heating systems.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If separate connection pieces are used for each pipe dimension, then the welding can be adapted to specific diameters, but the production and storage costs increase

Engineering Contradiction:
Improvediameter adaptationVSAvoidproduction cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent creates a universal electrofusion band design that can be used for all pipe diameters. The electrically conductive plastic heating element can be adjusted in length to accommodate different pipe sizes, eliminating the need for multiple diameter-specific connection pieces and significantly reducing production and storage costs.

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

Solution Approach 2:

The patent introduces flexibility and adjustability to the electrofusion band design. The heating element can be dynamically adjusted in length during installation to match different pipe diameters, allowing a single universal design to serve multiple applications without requiring pre-manufactured diameter-specific variants.

Inventive Principle:
Principle #15Dynamics

5Adaptability or versatility

If the heating element is designed as a continuous band, then the flexibility and universal use are improved, but the displacement between jacket and heating element may occur

Engineering Contradiction:
Improveuniversal useVSAvoidrelative position
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent merges the heating element and the jacket into a single co-extruded component manufactured in one continuous process. This integration eliminates the interface between separate parts, preventing displacement while maintaining the flexibility and universal applicability of the continuous band design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent performs the bonding action during the manufacturing process itself by co-extruding the heating element and jacket together. This preliminary bonding ensures that the relative position is fixed from the start, preventing displacement during subsequent handling and installation while maintaining the continuous band structure's flexibility.

Inventive Principle:
Principle #10Preliminary action

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 solution enables efficient, short welding times and uniform heating for all pipe diameters, reducing production and storage costs while ensuring occupational safety and flexibility in assembly.

Implementation Method 1

at least one heating element made of electrically conductive plastic... for supplying electrical energy to the heating element

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the jacket and heating element are fused together in the contact area... melts the fusion zone homogeneously

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3839319B1Electric welding strip, use and process
Publication Date: 2023.07.05 GEORG FISCHER ROHRLEITUNGSSYSTEME AG
  • EP3839319B1 patent drawingFigure 1~4
  • EP3839319B1 patent drawingFigure 5~7
  • EP3839319B1 patent drawingFigure 8~9

AI summary

Electrofusion strip (1) and method for its production for welding with plastic pipes, in particular for use in fixed-point fastening, comprising a sheath element (2), preferably made of electrically insulating plastic, at least one heating element (3) made of electrically conductive plastic, and at least two contact elements (6) for supplying electrical energy to the heating element, wherein the sheath element and the heating element are designed as strips, wherein the sheath element at least partially surrounds the heating element, wherein the contact elements are arranged in the opposing edge regions (4) of the heating element and extend parallel to each other along the heating element, wherein the sheath and heating element are designed as a co-extrusion part and are fused together in the contact area, and displacement between the sheath and heating element is completely prevented.