Internal Electroweldable Saddle Fitting for Buried PE Pipe Repair

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Solution Overview

Problem

Existing methods for welding polyethylene pipes require direct access and excavation, making them laborious and costly, especially when intervening on long or already laid pipes.

Innovation Solution

An electroweldable saddle-type fitting with heat-fusible components and wire windings allows for internal welding within the pipe, eliminating the need for external access and extensive excavation by using electric terminals to heat-fuse the fitting to both the pipe and a by-pass pipe, enabling secure and tight constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional external welding methods are used on polyethylene pipes, then direct access and excavation are required, but this increases labor costs and makes intervention on already laid pipes difficult

Engineering Contradiction:
Improveaccessibility for weldingVSAvoidwelding efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent inverts the traditional welding approach by performing welding from the internal side of the pipe rather than externally. The saddle-type fitting is inserted through an opening in the pipe, and welding is executed from inside the pipe using electric wire windings that contact the internal pipe surface, eliminating the need for external excavation and direct access.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The saddle-type fitting is inserted inside the pipe through an opening, nesting the fitting within the pipe's internal space. This allows the welding operation to be performed from within the pipe structure, transforming an external operation into an internal one that requires minimal external intervention.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If extensive excavation is performed to access pipes, then welding can be carried out, but this increases costs and disruption

Engineering Contradiction:
Improvewelding accessibilityVSAvoidexcavation material and labor
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent extracts the welding operation from the external environment and relocates it to the internal space of the pipe. By inserting the saddle-type fitting through a small opening and performing welding from inside, the method eliminates the need for extensive excavation and removal of surrounding material, significantly reducing loss of substance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The traditional approach of accessing pipes from the outside is inverted by performing all welding operations from the inside of the pipe. This inversion allows intervention on already laid pipes without excavation, as the fitting is inserted through an opening and welded internally to the pipe's inner surface.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of operation

If internal welding is used to avoid excavation, then access requirements are reduced, but the fitting structure becomes more complex

Engineering Contradiction:
Improveintervention accessibilityVSAvoidfitting structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The saddle-type fitting is divided into multiple functional components: a body portion that contacts the pipe internally, electric wire windings for heating, and a cylindrical sleeve for sealing and support. This segmentation allows each component to perform its specific function efficiently while maintaining overall simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The saddle-type fitting integrates multiple functions into a single device: it provides structural support, creates a tight seal against the pipe, conducts electric current for heating, and facilitates welding. This multi-functionality reduces the need for separate components and simplifies the overall intervention process despite the internal welding requirement.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 method enables efficient and cost-effective welding of polyethylene pipes without the need for extensive excavation, allowing for interventions on buried pipes of substantial length with reduced labor and costs.

Implementation Method 1

By passing electric current between the ends of the electric wire windings they are heated, causing the fusion of a portion of the fitting together with the components made of polyethylene associated with it

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3225896B1Electroweldable saddle-type fitting and relative welding method
Publication Date: 2019.09.04 NUPI IND ITAL
  • EP3225896B1 patent drawingFigure 1~2
  • EP3225896B1 patent drawingFigure 3~4
  • EP3225896B1 patent drawingFigure 5

AI summary

An electroweldable saddle-type fitting comprising a saddle-type wall (20') that defines on opposite sides a convex surface and a concave surface, wherein the saddle-type wall (20') is equipped with a predetermined curvature radius able to be coupled with the curvature radius of the heat-sealable pipe section, and wherein the saddle-type wall (20') is associated with at least one first electric wire winding (23), associated with the convex side and bearing a first pair of electric terminals (24) arranged on the concave side for the application of an electric current adapted to cause the heat fusion of the saddle-type wall (20'), the saddle-type fitting (10') being adapted to be welded inside a heat-sealable pipe by means of heat fusion of the convex side of the saddle-type wall (20') with the inner surface of the heat-sealable pipe, the electroweldable saddle-type fitting further comprising a cylindrical sleeve (27) made of heat-fusible material, provided with at least one further electric wire winding (28) bearing a further pair of electric terminals (29) for the application of an electric current, the further pair of electric terminals (29) also being arranged on the concave side of the saddle-type wall (20'), wherein the further electric wire winding (28) is arranged helically wound on the inner surface of the cylindrical sleeve (27) for the application of an electric current adapted to cause the heat fusion of the cylindrical sleeve (27) on a heat-sealable by-pass pipe.