Sandwich Panel Heating Cable Cavities for Uniform Temperature

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Solution Overview

Problem

Existing composite panels with integrated heating functions, such as those used in transportation and building sectors, face issues with temperature inhomogeneity, heat loss at edges, and insufficient coverage due to the limitations of heated films.

Innovation Solution

A sandwich panel design featuring thermally conductive skins, a soul with cavities to house a mono-conductor heating resistive cable, and a high coverage rate greater than 70%, which allows for homogeneous heat distribution and improved mechanical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heating films are used to provide heating function in sandwich panels, then heating capability is achieved, but temperature inhomogeneity occurs due to edge effects and heat concentration at film center

Engineering Contradiction:
Improvetemperature homogeneityVSAvoidheat loss at edges
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The heating function is segmented from the panel structure by using a separate heating cable housed in cavities within the core, rather than integrating heating elements directly into the skin layers. This segmentation allows independent optimization of heating distribution and panel thermal properties.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating cable is positioned within cavities in the core, allowing localized heat generation at the source. The cavities are strategically designed to distribute heat more evenly across the panel surface, addressing the edge effect problem by placing heating elements closer to panel edges where heat loss occurs.

Inventive Principle:
Principle #3Local quality

2Temperature

If heating films are integrated into sandwich panels, then heating function is provided, but coverage rate is insufficient due to poor adaptation to panel geometry

Engineering Contradiction:
Improveheating coverageVSAvoidadaptability to panel geometry
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The core structure serves multiple functions: it provides mechanical support, thermal insulation, and houses the heating cable through integrated cavities. This multi-functionality eliminates the need for separate heating film integration and allows the heating system to adapt to various panel geometries.

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

Solution Approach 2:

The heating cable is nested within cavities that are themselves nested within the core structure. This nested arrangement allows the heating elements to conform to the panel's geometry while maintaining structural integrity and achieving complete surface coverage.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of manufacture

If heating films are used for panel heating, then heating capability is achieved, but manufacturing flexibility is reduced due to required tooling changes for different panel geometries

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidadaptability to geometry changes
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The heating system design allows dynamic adaptation to different panel geometries without requiring fundamental changes to the heating element itself. The cable can be routed through cavities in various configurations to match different panel shapes and sizes, providing manufacturing flexibility.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system accommodates geometric variations by changing the arrangement and positioning of cavities within the core rather than changing the heating element design. This parameter adjustment approach maintains manufacturing consistency while adapting to different panel configurations.

Inventive Principle:
Principle #35Parameter changes

4Power

If double-conductor heating cables are integrated into panel layers, then high surface power management is achieved, but mechanical strength is reduced due to weak points created in the panel

Engineering Contradiction:
Improvesurface power capacityVSAvoidpanel mechanical strength
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The heating cable is extracted from the skin layers and placed within cavities in the core. This extraction removes the source of mechanical weakness from the load-bearing skin structure while maintaining the heating function, thereby preserving panel mechanical strength.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The core acts as an intermediary structure that houses the heating cable, isolating it from the load-bearing skin layers. This intermediary arrangement allows the heating cable to perform its function without compromising the mechanical integrity of the panel's primary structural elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 achieves a more uniform temperature distribution across the panel, reduces heat losses, and provides a higher coverage rate compared to traditional heated films, while maintaining mechanical integrity and flexibility in manufacturing.

Implementation Method 1

resistive heating cable

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4543142A1Sandwich panels incorporating heating function
Publication Date: 2025.04.23 KELOX RAILWAY FRANCE
  • EP4543142A1 patent drawingFigure 1~2
  • EP4543142A1 patent drawingFigure 3~4
  • EP4543142A1 patent drawingFigure 5~6

AI summary

The invention relates to a sandwich panel comprising a thermally conductive upper skin and a lower skin; a core disposed between the upper and lower skins; and a heating resistive cable. The panel is characterized in that the heating resistive cable is single-conductor, the core comprises one or more cavities, the single-conductor heating resistive cable being housed in one or more cavities of the core, and the coverage rate is greater than 70%. The invention also relates to its manufacturing process, its use in a railway or aeronautical vehicle, and an assembly, floor, or partition incorporating it.