Fusible Sleeve Pipe Fitting for Clamp-Free Induction Sealing

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Solution Overview

Problem

Existing pipe fittings for DWV systems face challenges in providing convenient, secure, and leak-resistant fluid sealing engagement with plastic pipes, often requiring encapsulated heating elements or clamps during induction heating.

Innovation Solution

A pipe fitting with a fusible sleeve made of thermoplastic material combined with an electrically conductive material, which heats and melts upon induction, allowing for electrofusion with the coupling body, enabling secure and leak-resistant connections without external clamps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional pipe fittings use mechanical gripping members or threaded connections, then the connection can be assembled and disassembled, but the fluid sealing engagement is not robust and prone to leaks

Engineering Contradiction:
Improvefluid sealing engagementVSAvoidassembly and disassembly convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The fusible sleeve utilizes phase transition of thermoplastic material from solid to molten state during induction heating, enabling the material to flow and fuse with the pipe and coupling body, creating a robust fluid-tight seal that cannot be achieved through mechanical connections alone

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The fusible sleeve is constructed as a composite material combining thermoplastic material with electrically conductive material (such as carbon black or metal particles), which enables both the fluid sealing function and the induction heating capability in a single integrated component

Inventive Principle:
Principle #40Composite materials

2Reliability

If encapsulated heating elements or clamps are used during induction heating, then the electrofusion can be achieved, but the device complexity increases and external components are required

Engineering Contradiction:
Improveelectrofusion connectionVSAvoidheating system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fusible sleeve serves itself by containing the electrically conductive material within its structure, generating heat through induction heating of its own material composition, eliminating the need for separate encapsulated heating elements or external clamps

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The heating function and the sealing function are merged into a single fusible sleeve component, where the electrically conductive material embedded in the thermoplastic material enables the sleeve to both seal the fluid connection and generate the necessary heat for fusion through induction heating

Inventive Principle:
Principle #5Merging (Combining)

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

Facilitates easy disassembly and reassembly for adjustments, while ensuring robust fluid sealing and resistance to leaks, eliminating the need for encapsulated heating elements.

Implementation Method 1

the electrically conductive material being located to heat or melt the thermoplastic material upon induction heating of the electrically conductive material

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 2

a fusible sleeve for electrofusion of a coupling body and a pipe upon induction heating

Methodology Applied
Scientific EffectElectrofusion:

Data Source

PatentEP4631703A1Pipe fitting with fusible sleeve
Publication Date: 2025.10.15 IPEX TECHNOLOGIES INC
  • EP4631703A1 patent drawingFigure 1~2
  • EP4631703A1 patent drawingFigure 3~4
  • EP4631703A1 patent drawingFigure 5~6

AI summary

A pipe fitting comprises a coupling body (40) and a fusible sleeve (60) sized to be received within the coupling body (40), the coupling body (40) comprising a sidewall (42) defining a bore (48) for receiving a pipe with the fusible sleeve (60) interposed between the two. The fusible sleeve (60) comprises a thermoplastic material combined with electrically conductive material, such as metal powder, stainless steel fibre or carbon fibre, arranged to melt the thermoplastic material upon induction heating. The fusible sleeve (60) has a tapered outer surface (74) for frictional engagement with an inner surface (52) of the sidewall. The frictional fit permits the coupling body (40) to be adjustably pre-mounted to the pipe without employing clamps, prior to induction welding being conducted. The coupling body (40) may take the form of an elbow, a T-connector, a cap (shown), amongst others.