Dual-Inner-Tube Insulated Conduit Spacing for Void-Free Foaming

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Solution Overview

Problem

In the continuous production of thermally insulated line pipes with two inner pipes, the displacement of inner pipes during the foaming process leads to inadequate thermal insulation and distance between them, causing inefficiencies and the formation of voids due to the use of traditional spacers which form thermal bridges and hinder foam expansion.

Innovation Solution

Intermediate spacers are inserted between the inner pipes at predetermined intervals along the longitudinal axis, held in place to maintain a minimum distance without forming thermal bridges, allowing unobstructed foam expansion and ensuring consistent insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional spacers are used to maintain distance between inner pipes, then the distance between inner pipes is maintained, but thermal bridges are formed and foam expansion is hindered

Engineering Contradiction:
Improvedistance between inner pipesVSAvoidthermal bridge formation
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The spacer is segmented into multiple independent support points (first support point, second support point, third support point, fourth support point) instead of a continuous structure. This segmentation allows the spacer to maintain distance between inner pipes while minimizing thermal bridge formation, as each support point is isolated and the overall thermal path is interrupted.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spacer has different structural properties at different locations - thicker sections at support points for stability and thinner sections between support points to minimize thermal conduction. This local variation in quality allows the spacer to perform its distance-maintaining function while reducing thermal bridge effects.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If traditional spacers are used to maintain distance between inner pipes, then the distance between inner pipes is maintained, but voids are formed during foaming process

Engineering Contradiction:
Improvedistance between inner pipesVSAvoidfoam expansion quality
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The spacer is divided into discrete support points rather than a continuous barrier, allowing foam to expand uniformly around the inner pipes without being blocked by large solid sections. The segmented structure provides minimal resistance to foam flow while still maintaining the required distance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spacer provides just enough support structure to maintain distance between pipes during foaming, but deliberately avoids excessive material that would block foam expansion. The thin-walled design and open structure between support points allow sufficient foam penetration while maintaining positional stability.

Inventive Principle:
Principle #16Partial or excessive action

3Manufacturing precision

If spacers are applied before foaming process, then distance between inner pipes is maintained, but the process cannot be used in continuous production

Engineering Contradiction:
Improvedistance between inner pipesVSAvoidcontinuous production capability
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The spacer is pre-assembled onto one inner pipe before the foaming process begins, establishing the correct distance configuration in advance. This preliminary positioning allows the spacer to be ready for immediate use during continuous production without requiring complex in-line adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spacer is designed to be automatically positioned and secured during the continuous feeding process through its own structural features (such as the engagement with inner pipe surfaces at multiple points), eliminating the need for additional external support structures or complex positioning mechanisms that would slow down production.

Inventive Principle:
Principle #25Self-service

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

The solution ensures precise maintenance of the required distance between inner pipes during the foaming process, preventing voids and thermal bridges, thus enhancing the thermal insulation properties and efficiency of the production process.

Implementation Method 1

The intermediate spacers used according to the invention are aids for foaming on continuous production plants... held in their inserted position between the two inner tubes by the latter in such a way that a minimum distance between the two inner tubes is not undercut... prevent the formation of cavities during the foaming process

Methodology Applied
Scientific EffectMechanical Force: Force

Implementation Method 2

the two inner pipes are continuously fed and foamed in order to form the thermal insulation layer... the expansion process of the polyurethane foam during the foaming process

Methodology Applied
Scientific EffectFoam expansion: Foam

Implementation Method 3

a thermal insulation layer arranged inside the outer pipe in which the two inner pipes are embedded... enhancing the thermal insulation properties

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4086060A1Method for the continuous production of a thermally insulated conduit
Publication Date: 2022.11.09 ISOPLUS FERNWARMETECHN
  • EP4086060A1 patent drawingFigure 1
  • EP4086060A1 patent drawingFigure 2~3
  • EP4086060A1 patent drawingFigure 4~5

AI summary

Method for the continuous production of a thermally insulated conduit (20) with two spaced-apart inner tubes (21, 22), an outer tube (23) accommodating the two inner tubes (21, 22), and a thermal insulation layer (24) arranged within the outer tube (23) in which the two inner tubes (21, 22) are embedded, wherein the two inner tubes (21, 22) are continuously fed and foamed in to form the thermal insulation layer (24), and the outer tube (23) is formed onto the thermal insulation layer (24), wherein during the continuous feeding of the two inner tubes (21, 22), intermediate spacers (27) are continuously inserted between the two inner tubes (21, 22) at predetermined intervals along the longitudinal axis, which are held in their inserted position between the two inner tubes (21, 22) by them, whereby a minimum distance between the two inner tubes (21, 22) are not undercut, after which the two inner tubes (21,22) with the inserted intermediate spacers (27) are subjected to the foaming process.