Electro-inductive Insert for Thermoplastic Pipe Pull-out Protection

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Solution Overview

Problem

Push-in socket joints for pipes lack effective pull-out protection, particularly in vertically laid drainpipes and sewage pipes, and existing solutions like mechanical retaining clips or electrofusion couplers are either complex or costly.

Innovation Solution

An electro-inductively heatable insert is placed between the spigot end and socket, allowing for welding of the thermoplastic pipes when needed, providing a secure connection without compromising the sealing effect, and can be easily integrated during pipe assembly or only when required for pull-out protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical retaining clips are used for pull-out protection, then the pipe connection becomes secure against unintentional pulling out, but the device complexity increases and larger installation space is required

Engineering Contradiction:
Improvepull-out protectionVSAvoidmechanical retaining clips
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the pull-out protection function from separate mechanical retaining clips and integrates it into a compact insert element that is inserted into the socket joint. This insert contains a retention mechanism that provides pull-out protection without requiring external clips or additional installation space, thus reducing device complexity while maintaining reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The insert element with integrated retention mechanism is nested within the socket joint structure. The insert is inserted into the annular gap between the spigot end and the socket, and the retention features are nested within the insert itself, allowing pull-out protection to be provided in a space-efficient manner without increasing overall device complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If separate electrofusion couplers with heating coils are used for pull-out protection, then the pipe connection becomes secure, but the manufacturing cost increases significantly

Engineering Contradiction:
Improvepull-out protectionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the pull-out protection function with a simple insert element that does not require separate electrofusion couplers or heating coils. The insert provides retention through its structural design, eliminating the need for expensive electrofusion equipment and reducing manufacturing costs while maintaining connection security

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The insert element is designed as a simple, inexpensive component that can be easily manufactured and installed. Rather than using expensive electrofusion couplers, the insert provides the necessary pull-out protection at low cost, making it an economical solution for securing pipe connections

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If an electro-inductively heatable insert is used for welding, then the pipe connection becomes stable and secure, but the device complexity increases compared to simple push-fit joints

Engineering Contradiction:
Improvewelding connectionVSAvoidelectro-inductive heating system
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical welding systems with electro-inductive heating. The insert contains an electro-inductively heatable element that, when exposed to an alternating magnetic field, generates heat through eddy currents to melt and weld the thermoplastic materials. This substitution simplifies the overall system by using electromagnetic fields instead of complex mechanical heating devices

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

Solution Approach 2:

The electro-inductively heatable insert acts as an intermediary that facilitates welding between the spigot end and socket. The insert's heating element transfers thermal energy to the thermoplastic materials at the joint interface, enabling material union and secure connection without requiring direct contact between the pipe components

Inventive Principle:
Principle #24Intermediary (Mediator)

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 a simple and cost-effective implementation of pull-out protection for push-in socket joints, ensuring a stable pipe connection while maintaining the ease of assembly and low cost of conventional push-fit connections.

Implementation Method 1

an electro-inductively heatable insert is arranged in the annular gap between the spigot end and the socket. By electro-inductively heating the insert, the thermoplastic material on the facing surfaces of the spigot end and the socket is heated

Methodology Applied
Scientific EffectElectro-inductive heating: Electromagnetic Induction

Implementation Method 2

an alternating electromagnetic field is applied from outside the sleeve, which inductively generates eddy currents in the insert, as a result of which the insert is heated

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

the thermoplastic material on the facing surfaces of the spigot end and the socket is heated and brought into a plastic state, as a result of which material union occurs and welding of the two pipes is achieved

Methodology Applied
Scientific EffectPhase transition to plastic state: Phase Change

Data Source

PatentEP3093546B1Socket joint for pipes made of thermoplastic material
Publication Date: 2019.10.30 PIPELIFE AUSTRIA
  • EP3093546B1 patent drawingFigure 1~3
  • EP3093546B1 patent drawingFigure 4~5

AI summary

In a push-fit connection for pipes made of thermoplastic material, in which the spigot end (1) of a first pipe (2) is inserted into the end of a second pipe (4) which is flared to form a socket (5), an electro-inductively heatable insert (9) is arranged in the annular gap (11) between the spigot end (1) and the socket (5).