Induction-Heated Electrofusion Fitting for Leak-Safe Lined Pipe Joining

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Solution Overview

Problem

Existing electrofusion fitting methods for joining lined pipes may compromise the integrity of the pipe linings and host pipes due to potential fluid leak paths through electrical leads, and are not suitable for closed bevel automatic pipeline welding processes, particularly in subsea applications.

Innovation Solution

The use of heating elements on the outer surface of the electrofusion fitting, powered by electromagnetic induction, eliminates the need for electrical leads and contacts, minimizing fluid leak paths and enabling reliable welding without direct electrical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If electrical leads are extended through the electrofusion fitting to power heating coils, then the heating function is achieved, but fluid leak paths are created compromising pipe integrity

Engineering Contradiction:

Improveheating capabilityVSAvoidpipe integrity

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent replaces the electrical conduction system (electrical leads passing through the fitting) with an electromagnetic induction system. An induction coil generates a magnetic field that induces eddy currents in the heating element, which is electrically isolated from the fitting interior. This substitution eliminates fluid leak paths while maintaining heating capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary electromagnetic field between the power source and the heating element. The induction coil generates the magnetic field, which then induces currents in the heating element without direct electrical contact. This intermediary field transfers energy while keeping the heating element electrically isolated from the fitting interior, preventing fluid leakage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If electrical leads are passed through the gap between adjacent metal pipe lengths, then heating power is delivered, but the method is incompatible with closed bevel automatic welding processes

Engineering Contradiction:

Improveelectrical power deliveryVSAvoidcompatibility with welding processes

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical approach of routing electrical leads through pipe gaps with an electromagnetic induction system. The induction coil and heating element configuration allows power delivery without physical lead extension, enabling compatibility with closed bevel automatic welding processes where the gap is sealed.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If heating elements are placed on the outer surface of the electrofusion fitting, then electrical isolation is achieved, but heating efficiency must be maintained without direct electrical contact

Engineering Contradiction:

Improveelectrical isolationVSAvoidheating efficiency

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces direct electrical contact heating with electromagnetic induction heating. The induction coil generates a magnetic field that penetrates the fitting wall and induces eddy currents in the heating element on the outer surface. This substitution maintains heating efficiency while achieving complete electrical isolation, as energy is transferred through the electromagnetic field rather than direct contact.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the energy transfer parameter from electrical conduction to electromagnetic induction. By utilizing the magnetic permeability and electrical conductivity parameters of the heating element material, the system achieves efficient heating through induced eddy currents without direct electrical contact, maintaining heating efficiency while improving reliability.

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 approach enhances the reliability of electrofusion fittings by eliminating fluid ingress risks, simplifying the manufacturing process, reducing testing requirements, and ensuring consistent heating, thereby improving the integrity and efficiency of pipe welds.

Implementation Method 1

Each heating element is configured to heat at least an associated portion of the electrofusion fitting in response to electromagnetic induction

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3785887B1Joining or repairing lined pipes

Publication Date: 2024.06.19 PIONEER LINING TECH

Figure 1~2
Figure 3~4

AI summary

An electrofusion fitting (101) for joining liners (105a, 105b) of sections of lined pipe (103a, 103b), each liner (105a, 105b) being within a metal host pipe of a respective section of lined pipe (103a, 103b). The electrofusion fitting (101) comprises at least one heating element (107a, 107b) disposed on or in an outer surface of the electrofusion fitting (101). The, or each, heating element (107a, 107b) is electrically isolated from an inner surface of the fitting (101) and is configured to heat an associated portion of the electrofusion fitting (101) in response to electromagnetic induction.