Electrofusion Fitting With Elastic Pipe Stop for Slip-On Assembly

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Solution Overview

Problem

Existing electrofusion fittings for plastic pipelines face challenges in efficient and damage-free assembly, particularly when used as slip-on fittings, due to the complexity of removing internal stops and the risk of damaging the inner diameter during installation.

Innovation Solution

An electrofusion fitting with a flexible, elastic pipe stop on the inner surface that tilts to form a stable stop for pipe ends, allowing easy insertion and removal without tools, and features a recess for guiding a heating wire through a single operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed pipe stop is used in the electrofusion fitting, then the insertion depth of pipe ends can be verified, but the stop must be removed for slip-on fitting installation which is time-consuming and damages the inner diameter

Engineering Contradiction:
Improveinsertion depth verificationVSAvoidease of stop removal
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The pipe stop is designed as an elastic element that can dynamically change its state between providing a stable stop function and being easily removable. The elastic property allows the stop to be pressed against the inner surface for stable operation during pipe insertion verification, then easily removed by applying force in the opposite direction for slip-on fitting installation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The pipe stop's mechanical properties are changed by using an elastic material that can deform under pressure. This parameter change allows the stop to transition from a rigid obstacle that damages the inner surface to a compliant element that can be easily removed without damage, resolving the contradiction between verification stability and removal ease.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a robust fixed stop is used, then the insertion depth control is stable, but the removal process is complex and time-consuming

Engineering Contradiction:
Improvestop stabilityVSAvoidtime for stop removal
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The elastic pipe stop provides stability during normal operation when pressed against the inner surface, then allows rapid removal by reversing the pressing force. This dynamic behavior eliminates the time loss associated with removing robust fixed stops while maintaining stability during pipe insertion verification.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the pipe stop is made elastic, then it can be easily removed without damaging the inner surface, but it must provide stable stop function during operation

Engineering Contradiction:
Improveease of stop removalVSAvoidstop function reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The elastic pipe stop changes its mechanical state based on applied force. During normal operation, the stop is pressed against the inner surface, providing reliable insertion depth verification. When removal is needed, reversing the force causes the elastic element to detach easily without damaging the inner surface, thus maintaining both reliability and ease of operation.

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

Enables reliable assembly of plastic pipelines without additional effort, ensuring a stable weld while minimizing damage to the inner surface and simplifying the installation process.

Implementation Method 1

a heating wire winding (4) inside to weld the pipes to the fitting

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The elastic design of the pipe stop allows it to be attached to the inner surface of the body via a slight, unstable connection, enabling easy removal if necessary. Nevertheless, the pipe stop provides a stable stop for the pipe ends.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3865756B1Electric welding fitting
Publication Date: 2026.04.22 GEORG FISCHER WAVIN AG
  • EP3865756B1 patent drawingFigure 1~2
  • EP3865756B1 patent drawingFigure 3~4
  • EP3865756B1 patent drawingFigure 5

AI summary

Electro-welding fitting (1) made of plastic for welding plastic pipes comprising a cylindrical body (2), a longitudinal axis (3), a heating wire winding (4), contacts (5) for supplying the electric current and a pipe stop (6), wherein the pipe stop is arranged on the inner surface (7) of the body, wherein the pipe stop is flexible or elastic.