Plastic Pipe Coupling With Resistance Wire for Fast On-Site Joining

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Solution Overview

Problem

Existing methods for joining plastic pipe elements, such as heat-fusion and electrically weldable connections, are limited by specific diameter ranges, require skilled labor, are time-consuming, and involve high costs due to the need for specialized equipment and complex preparation processes, making them inefficient and expensive for on-site implementation.

Innovation Solution

An electrically weldable connection device featuring a resistance wire wound on the outer surface of the pipe element and a clamp to secure the connection, allowing for pre-assembly and on-site assembly without permanent welding, enabling connections across various diameters and reducing labor and equipment costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heat-fusion socket joining is used, then joining is achieved for specific diameter ranges, but it requires specialized equipment, skilled labor, and complex preparation processes

Engineering Contradiction:
Improvejoining reliabilityVSAvoidequipment and process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the complex mechanical heat-fusion system with a simpler electrically weldable system using resistance wires embedded in fittings. This substitution eliminates the need for temperature-regulated fusion welders and matrix maintenance, achieving reliable joining through electrical resistance heating instead of complex thermal control mechanisms.

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

Solution Approach 2:

The patent creates universal pipe segments with embedded resistance wires that can be directly connected on-site without specialized equipment. The fitting design with integrated resistance wires and fusion indicators provides multi-functionality, enabling both joining and process verification through a single component, eliminating the need for separate temperature control and monitoring systems.

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

2Reliability

If electrically weldable joining with embedded resistance is used, then joining is achieved through Joule heating, but the process is extremely slow requiring 20-30 minutes

Engineering Contradiction:
Improvejoining reliabilityVSAvoidjoining speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent optimizes the electrical parameters by using low-voltage current (24-40 V) that generates sufficient Joule heating quickly. The resistance wire configuration and power supply parameters are adjusted to reduce heating time from 20-30 minutes to a faster process, while maintaining reliable welding through controlled thermal parameters.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary preparation of pipe ends by scraping and cleaning before joining, which reduces the actual welding time. The resistance wires are pre-positioned in fittings during manufacturing, eliminating the need for on-site wire installation and ensuring proper alignment before the rapid welding process begins.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If thorough tube preparation is performed to prevent tolerance differences, then joining precision is improved, but labor cost and time increase significantly

Engineering Contradiction:
Improvejoining precisionVSAvoidpreparation ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent uses self-centering fittings with embedded resistance wires that automatically align with pipe ends during insertion. The fitting design includes features that guide the pipe into proper position, eliminating the need for skilled operators to manually align and prepare tube ends with high precision, while still achieving accurate joining.

Inventive Principle:
Principle #25Self-service

4Reliability

If butt welding with hydraulic units and special clamps is used for large diameters, then joining is achieved, but the process is significantly slower requiring 40-120 minutes per joining

Engineering Contradiction:
Improvejoining reliabilityVSAvoidjoining time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the slow hydraulic heating and clamping system with a faster electrical resistance welding system. The embedded resistance wires provide direct heating without requiring hydraulic pressure application and maintenance, reducing joining time from 40-120 minutes to a much faster process while maintaining reliable connections through controlled thermal fusion.

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

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

The solution provides a cost-effective, efficient, and versatile connection method that eliminates the need for skilled labor, reduces installation time, and prevents tube wastage, while allowing connections of different thicknesses and a wide range of fittings without atmospheric limitations.

Implementation Method 1

the melting temperature is reached as a result of an electrical resistance that is embedded in an electrically weldable fitting, is often used. The terminals of the welding connector of the fitting are connected to the cables of an electric welding unit and the current generated by the machine heats the resistance by Joule effect.

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3456520B1Coupling device for pipe elements
Publication Date: 2021.01.20 ABN PIPE SYST
  • EP3456520B1 patent drawingFigure 1
  • EP3456520B1 patent drawingFigure 2~3
  • EP3456520B1 patent drawingFigure 4~5

AI summary

The present invention relates to a connection device for plastic pipe elements (1) which allows performing pre-assembly and being finally assembled without requiring skilled labor, comprising a pipe element (1) having at least one end, a plastic connection element (2) which is connected to an outer surface of said pipe element (1) through said end, which comprises a resistance wire (3) wound on the outer surface of the pipe element (1) itself.