Expanded Metal Mesh for Low Voltage Pipe Electrofusion

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Solution Overview

Problem

Existing methods for joining and repairing thermally insulated pipe systems using weldable plastic materials pose safety hazards due to high voltage requirements and can result in low-quality joints, especially when accessing buried pipes, which are difficult and costly to maintain.

Innovation Solution

A method utilizing an expanded metal mesh conductive band with a high open area, diagonally arranged metal strands, and a low voltage direct current power supply for electrofusion welding, ensuring even heat distribution and high-quality joint formation, while maintaining operator safety through reduced voltage and increased stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high voltage power supply is used for electrofusion welding, then welded joint quality is improved, but safety hazards to operators increase

Engineering Contradiction:
Improvewelded joint qualityVSAvoidsafety hazards
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the voltage parameter from high voltage to low voltage (below 50V) while compensating through increased current and optimized heating time. This parameter transformation maintains welding effectiveness while eliminating safety hazards associated with high voltage, directly resolving the technical contradiction between joint quality and operator safety

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an electrically conductive band as an intermediary element between the power supply and the pipe material. This band acts as a heat transfer medium that distributes electrical energy evenly across the welding surface, enabling effective heating at low voltage while ensuring uniform temperature distribution for high-quality joints

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If conventional welding methods are used, then welded joint quality may be compromised, but safety risks are reduced

Engineering Contradiction:
Improvewelded joint qualityVSAvoidsafety reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent transforms the welding parameters by using low voltage (below 50V) combined with optimized current density and heating duration. This parameter change enables the use of electrofusion welding with enhanced safety while maintaining or improving joint quality through better heat distribution control

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The electrically conductive band serves as a mediator that enables safe low-voltage welding while achieving high-quality joints. It distributes electrical energy uniformly across the welding surface, preventing localized overheating and ensuring consistent fusion quality without requiring high voltage

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If high voltage electrofusion welding is used, then heating efficiency is improved, but temperature distribution uniformity deteriorates

Engineering Contradiction:
Improveheating efficiencyVSAvoidtemperature distribution uniformity
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The electrically conductive band acts as an intermediary that distributes electrical energy uniformly across the entire welding surface. This intermediate layer ensures even heat generation throughout the contact area, preventing hot spots and achieving uniform temperature distribution while maintaining heating efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the heating approach by using low voltage with optimized current density through the conductive band. This parameter transformation enables controlled, uniform heating across the welding surface, achieving both heating efficiency and temperature uniformity simultaneously

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 method achieves high-quality, reliable welded joints with reduced safety risks for workers and improved maintenance efficiency by using a low voltage power supply and ensuring even heat distribution, thus enhancing the mechanical strength and longevity of the pipe system.

Implementation Method 1

a low voltage direct current power supply for electrofusion welding, ensuring even heat distribution and high-quality joint formation

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The specific configuration of the conductive band which is formed of expanded metal mesh provides that the supplied energy, heat, is evenly distributed in the joint region, since the metal strands cross each other

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

where the material of the sleeve coupling and the material pipe can melt and fuse together by electrofusion, a high quality joint is formed

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3749506B1The method for joining or repairing a pipe system
Publication Date: 2023.06.07 TSC INNOVATION AB
  • EP3749506B1 patent drawingFigure 1
  • EP3749506B1 patent drawingFigure 2a~2e
  • EP3749506B1 patent drawingFigure 3~5

AI summary

The invention relates to a method for joining or repairing a pipe system comprising at least two bonded pipes having outer casing. The method comprising the steps of forming a joint region by fitting a sleeve coupling of weldable polyethylene on the outside surface of a pipe end such that the sleeve coupling overlaps the pipe end and inserting an electrically conductive band between the outside surface of the pipe end and the inside surface of the sleeve coupling, wherein the electrically conductive band is configured of expanded metal mesh having metal strands and mesh openings, and arranging the expanded metal mesh such that the metal strands extend substantially diagonally across the width of the conductive band, electrofusion welding of the joint region in order to form a weld joint by supplying power to the electrically conductive band, application of a pressure force on the joint region during the electrofusion welding by a welding tool for pressurizing the joint region, and extrusion welding a longitudinal join formed on the sleeve coupling.