Fire-resistant Cable Cementitious Starch Composite

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Solution Overview

Problem

Existing fire-resistant electrical and optical cables lack satisfactory fire resistance, flexibility, and compatibility with mechanical and dielectric properties, and their production methods are costly and inefficient.

Innovation Solution

A fire-resistant electrical and optical cable with an electrically insulating composite layer composed of cementitious materials and starch, which forms a porous structure at high temperatures, providing thermal insulation and maintaining mechanical integrity, along with a manufacturing process that is simple and cost-effective.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polymer-based electrically insulating layers with flame retardant additives are used, then fire resistance is improved, but fire resistance remains insufficient and mechanical properties deteriorate at high temperatures

Engineering Contradiction:
Improvefire resistanceVSAvoidmechanical properties at high temperature
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite material consisting of at least two different cementitious materials (e.g., calcium silicate and calcium aluminate) combined in specific proportions (40-60% and 60-40% respectively). This composite approach creates a synergistic effect where the combination of different cementitious materials provides both fire resistance and maintained mechanical properties at high temperatures, overcoming the limitations of single-material solutions and polymer-based alternatives.

Inventive Principle:
Principle #40Composite materials

2Reliability

If multi-layer insulating strips with mica and glass fibers are used, then fire resistance is improved, but production cost increases and space requirements increase

Engineering Contradiction:
Improvefire resistanceVSAvoidproduction complexity and space
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple separate layers (insulating strips with mica and glass fibers) into a single monolithic electrically insulating layer made of cementitious material. This consolidation eliminates the need for multiple superimposed layers, reducing production complexity, preparation time, and space requirements while maintaining or improving fire resistance properties.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cementitious material layer serves multiple functions simultaneously: it provides electrical insulation, fire resistance, mechanical strength, and structural integrity in a single component. This multi-functionality replaces the need for separate specialized layers, simplifying the overall cable structure and manufacturing process.

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

3Reliability

If fire-resistant materials are used, then fire resistance is improved, but flexibility and adhesion deteriorate

Engineering Contradiction:
Improvefire resistanceVSAvoidflexibility and adhesion
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent optimizes the chemical composition parameters of the cementitious material, specifically controlling the proportions of different cementitious materials (40-60% and 60-40% ranges) and adjusting water content (15-30% by weight). These parameter changes enable the material to achieve a balance between fire resistance and flexibility, allowing the cable to be bent and manipulated while maintaining adhesion and structural integrity.

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

The cable achieves excellent fire resistance, flexibility, and mechanical properties, meeting stringent fire resistance standards while maintaining cohesion and thermal protection, and the manufacturing process is rapid and economical.

Implementation Method 1

Hardening occurs by simple hydration of calcium aluminates and calcium silicates and the binder cement paste retains its strength and stability after hardening

Methodology Applied
Scientific EffectHydration: Hydrolysis

Implementation Method 2

the electrically insulating composite layer... forms a porous structure when this layer is exposed to temperatures greater than or equal to 1000°C for a period of up to 120 min... This porous and rigid structure contains air which by nature is an excellent thermal insulator

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3387654B1Fire-resistant cable
Publication Date: 2021.03.10 NEXANS SA
  • EP3387654B1 patent drawingFigure 1~2

AI summary

The present invention relates to a fire-resistant cable comprising at least one electrically insulating composite layer made from a cementitious material and at least one starch, and method for producing same.