Induction Coupling Sleeve Structure for Strong Plastic Pipe Welding

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Solution Overview

Problem

Existing induction connection sleeves for plastic pipes face challenges such as limited connection with the inner surface and difficulty in positioning induction heating elements, leading to uneven heating and poor connection quality.

Innovation Solution

A method involving an induction connection sleeve with a sleeve body having an inner part and an outer part, where the inner part is made from a thermoplastic with a lower melting point and the outer part from a thermoplastic with a higher melting point, allowing precise positioning of induction heating elements and ensuring even heating and strong connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If induction heating elements are not surrounded by the sleeve body on their inner surface, then the plastic pipe can be inserted easily, but the connection between the plastic pipe and the induction heating elements is limited

Engineering Contradiction:
Improveease of insertionVSAvoidconnection strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The induction connection sleeve is divided into an inner part and an outer part. The inner part contains the induction heating elements and provides the connection surface, while the outer part provides structural support. This segmentation allows the inner part to be optimized for connection strength without compromising ease of insertion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner part acts as an intermediary between the induction heating elements and the plastic pipe. It surrounds the induction heating elements on their inner surface, providing an extended connection surface that enhances the bond between the heating elements and the pipe while maintaining easy insertion.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If induction heating elements are surrounded by the sleeve body on their inner surface, then the connection strength is improved, but the positioning of induction heating elements during manufacturing becomes very difficult

Engineering Contradiction:
Improveconnection strengthVSAvoidpositioning difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

Dividing the sleeve into inner and outer parts allows the induction heating elements to be positioned and fixed in the inner part during manufacturing. The inner part can be designed with positioning features that make assembly easier, while the outer part is added subsequently to provide the surrounding structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner part is manufactured first with the induction heating elements already positioned and surrounded. This preliminary action ensures correct positioning during manufacturing, and then the outer part is added to complete the sleeve structure, maintaining both ease of manufacture and connection strength.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the induction connection sleeve is pushed completely over the first plastic pipe, then the second plastic pipe can be positioned precisely, but the manufacturing complexity increases

Engineering Contradiction:
Improvepositioning precisionVSAvoidsleeve structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The sleeve is segmented into inner and outer parts that can be manufactured separately and then assembled. This segmentation allows the inner part to be optimized for precise positioning when pushed over the first plastic pipe, while the outer part provides structural support, managing overall complexity through modular design.

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

The method enables a stable and strong connection between plastic pipes with improved dimensional accuracy and even heating, ensuring high strength and tightness of the welded joint.

Implementation Method 1

Positioning an inducing device in the region of the induction connection sleeve and inducing a current in the induction connection sleeve by means of the inducing device so that the sleeve body at least partially softens

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

inducing a current in the induction connection sleeve by means of the inducing device so that the sleeve body at least partially softens

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

the inner part is made from a thermoplastic with a lower melting point

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3800034B1Method for producing a welded connection between a first plastic pipe and a second plastic pipe
Publication Date: 2024.02.28 AGRU KUNSTSTOFFTECHNIK
  • EP3800034B1 patent drawingFigure 1
  • EP3800034B1 patent drawingFigure 2~3
  • EP3800034B1 patent drawingFigure 4~6

AI summary

The invention relates to a method for producing a welded joint between a first plastic pipe (2) and a second plastic pipe (3). The method comprises the following steps: providing the first plastic pipe (2); providing an induction coupling sleeve (1) with a sleeve body (9) having a width (46) in the axial direction; sliding the induction coupling sleeve (1) onto the first plastic pipe (2) so that the induction coupling sleeve (1) surrounds the first plastic pipe (2) with its entire width (46) of the sleeve body (9); providing the second plastic pipe (3); coaxially aligning and directly adjoining the second plastic pipe (3) relative to the first plastic pipe (2); axially displacing the induction coupling sleeve (1) so that it partially surrounds the first plastic pipe (2) and the second plastic pipe (3);Positioning an induction device (69) in the area of ​​the induction connection sleeve (1) and inducing a current in the induction connection sleeve (1) by means of the induction device (69), so that the sleeve body (9) is at least partially plasticized and forms a material bond with the two plastic pipes (2, 3).