Fire-Resistant Cable with Polymer-Metal Composite Barrier
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Solution Overview
Problem
Existing fire-resistant electrical cables fail to maintain their integrity and impermeability to water under intense mechanical stresses and high temperatures, as their materials soften or combust, leading to structural collapse and water penetration.
Innovation Solution
The electrical cable features discontinuously stratified inorganic insulating material in direct contact with conductive material, an outer polymer-metal composite barrier, and no continuous thermally collapsible elastomeric or thermoplastic layers, ensuring thermal stability and structural integrity up to 1100°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If continuous layers of thermoplastic or elastomeric material are used in the cable structure, then ease of manufacture and flexibility are improved, but fire resistance and structural integrity at high temperatures deteriorate due to material softening and collapse
Solution Approach 1:
The patent removes continuous thermoplastic or elastomeric layers from the cable structure, extracting the problematic material that causes collapse at high temperatures. This extraction eliminates the fire resistance issue while maintaining manufacturing simplicity through the use of alternative inorganic materials like glass fibre and mica tape that can be applied in discontinuous layers.
Solution Approach 2:
The patent changes the material parameters from organic thermoplastic/elastomeric materials to inorganic materials (glass fibre, mica tape) that maintain structural integrity at high temperatures. This parameter change transforms the cable's thermal stability while preserving manufacturing feasibility through standard cable construction techniques.
2Reliability
If thermoplastic or elastomeric layers are used for insulation and protection, then electrical insulation and mechanical protection are improved, but impermeability to water under fire conditions deteriorates due to thermal collapse
Solution Approach 1:
The patent employs composite material structures combining glass fibre tapes, mica tapes, and polymer resin coatings to replace traditional thermoplastic layers. This composite approach maintains electrical insulation properties while providing fire-resistant protection that prevents water penetration during fire conditions, as the inorganic materials do not collapse at high temperatures.
3Reliability
If traditional cable structures with multiple layers are used, then comprehensive protection is improved, but device complexity increases
Solution Approach 1:
The patent segments the protective structure into discontinuous layers of glass fibre tape, mica tape, and polymer resin coatings applied in a simplified sequence. This segmentation maintains comprehensive protection against fire, water, and mechanical damage while reducing overall structural complexity compared to traditional multi-layer continuous constructions.
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 cable maintains high impermeability to water and resistance to mechanical stresses even at temperatures above 1000°C for extended periods, preserving electrical performance and structural integrity during fires and rescue operations.
Implementation Method 1
each individual wire is encompassed by a glass fibre strip onto which a mica layer has been glued
Implementation Method 2
maintain their characteristics of fire resistance and impermeability to water even in the presence of the intense mechanical stresses
Implementation Method 3
a layer of polymer resin optionally charged with refractory inorganic particles
Implementation Method 4
one layer of braided glass fibres impregnated with polymer resin optionally charged with refractory inorganic particles
Implementation Method 5
an outer sheath of polymer resin optionally charged with refractory inorganic particles
Implementation Method 6
resistant to flames and dielectric breaks when subjected to temperatures of 800°C-1000°C for more than 15 minutes
Data Source
Figure 1a~1b
Figure 2a~2b
AI summary
What is described is an electrical cable comprising at least one conductor and a barrier arranged externally to the at least one conductor. The barrier comprises two first layers comprising an inorganic material and a second layer comprising a polymer-metal composite material, the second layer being interposed between the two first layers. The electrical cable also comprises, in an intermediate position between the at least one conductor and the barrier, solely discontinuous layers and/or layers of non-thermally-collapsible materials.