Fire Resistant Optical Cable Ceramifiable Tubular Layer
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Solution Overview
Problem
Conventional fire-resistant optical cables face challenges in maintaining high fiber density, flexibility, and optical transmission capability during and after a fire, with existing solutions often increasing manufacturing costs and failing to minimize signal attenuation and mechanical damage.
Innovation Solution
A fire-resistant optical cable design featuring a tubular layer of ceramifiable material protected by a flame shielding layer, which delays exposure to flames, allowing the ceramifiable material to transform into a robust ceramic that withstands mechanical stresses and maintains optical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fire-resistant protections are used, then fire resistance is improved, but fiber density is reduced and manufacturing costs increase
Solution Approach 1:
The patent implements a nested structure where optical fibers are first grouped into micromodules, then multiple micromodules are arranged within a tubular layer of ceramifiable material, which is subsequently surrounded by a flame shielding layer. This nested arrangement maximizes fiber density while maintaining fire resistance, as each level of nesting efficiently utilizes space without requiring excessive protective material between individual fibers.
Solution Approach 2:
The patent employs composite materials by combining ceramifiable material (which transforms into ceramic under fire) with flame shielding layer materials. This composite structure provides enhanced fire resistance compared to conventional single-material protections, allowing thinner overall protection layers that maintain high fiber density while meeting fire resistance requirements.
2Reliability
If conventional fire-resistant protections are used, then fire resistance is improved, but manufacturing complexity and costs increase
Solution Approach 1:
The nested structure of micromodules within the tubular layer simplifies manufacturing by enabling modular assembly. Micromodules can be pre-assembled and then inserted into the tubular layer in an organized sequence, reducing the complexity of handling and positioning individual fibers during cable construction compared to conventional methods requiring complex multi-layer jackets.
Solution Approach 2:
The patent segments the protective structure into distinct functional layers: micromodules for fiber organization, tubular layer for structural protection and ceramic transformation, and flame shielding layer for heat resistance. This segmentation allows each component to be manufactured and quality-tested separately, simplifying the overall manufacturing process and reducing complexity compared to conventional integrated multi-layer 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 solution effectively reduces signal attenuation and mechanical damage during and after a fire, ensuring continuous optical transmission and mechanical protection of the fibers.
Implementation Method 1
at least one flame shielding layer surrounding said tubular layer, said flame shielding layer being able to delay an exposure of said tubular layer to flames
Implementation Method 2
tubular layer of a ceramifiable material which, when exposed to an intense heating, e.g. caused by fire, at least partially burns and forms a coherent ceramic material
Implementation Method 3
the above materials can collapse onto the optical fibers, which, being to a large extent devoid of their polymeric coatings (since during fire they has been mainly burned off), are extremely sensitive to any mechanical stress
Data Source
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AI summary
A fire resistant optical cable (10) comprising: a plurality of optical fibers (11); at least one tubular layer of a ceramifiable material (13) surrounding the plurality of optical fibers; at least one flame shielding layer (16) surrounding the tubular layer. The tubular layer of the ceramifiable material (13) is able to mechanically protect the optical fibers not only during heating but also when the fire is extinguished, since it forms a sufficiently robust layer to withstand the mechanical stresses caused by the collapsing of the materials still surrounding the cable, especially in the transitions portions between hot and cold zones. The tubular layer of the ceramifiable material is protected by means of at least one flame shielding layer which prevents the flames to directly act onto the ceramifiable material.