Air-Blown Optical Fibre Unit With Low-Strength Inner Layer
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Solution Overview
Problem
Existing blown optical fibre units face issues with fibre breakout failure during the removal of the inner layer, leading to damage of the optical fibres due to strong bonding between the fibre coating and the inner layer materials, which are often acrylate-based and not adequately cured.
Innovation Solution
An optical fibre unit design featuring an inner layer with low tensile strength (0.1 MPa to 1 MPa) and elongation at break (20% to 35%), allowing safe removal without damaging the fibres, while an outer layer with higher tensile strength (10 MPa to 60 MPa) provides necessary stress resistance for deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inner layer uses acrylate-based material with high tensile strength to provide structural support, then the outer layer gains sufficient strength for deployment, but the bonding between the fibre coating and inner layer becomes too strong, causing fibre breakout failure during removal
Solution Approach 1:
The patent changes the key parameter of the inner layer material from high tensile strength to low tensile strength (0.1-1 MPa). This parameter change allows the inner layer to be easily removed without causing fibre breakout, while the outer layer maintains its high tensile strength (10-60 MPa) for structural support during deployment.
Solution Approach 2:
The patent applies different material properties to different layers: the inner layer uses soft material with low tensile strength specifically for easy removal, while the outer layer uses hard material with high tensile strength for structural support. This local differentiation of material qualities resolves the contradiction between easy removal and structural integrity.
2Ease of operation
If the inner layer material is made soft and flexible to allow easy removal, then fibre breakout failure is reduced, but the overall structural strength and stress resistance of the optical fibre unit is compromised
Solution Approach 1:
The patent divides the protective structure into two separate layers with distinct functions: the inner layer provides ease of removal with low tensile strength, while the outer layer provides structural strength with high tensile strength. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The patent uses a composite structure combining two different materials: a soft inner layer material (tensile strength 0.1-1 MPa) and a hard outer layer material (tensile strength 10-60 MPa). This composite approach allows the unit to exhibit both ease of removal and high stress resistance simultaneously.
3Reliability
If the inner layer is made with high elongation at break to allow safe removal, then fibre integrity during removal is maintained, but the layer becomes too difficult to remove completely without residue
Solution Approach 1:
The patent optimizes the elongation at break parameter of the inner layer to a specific range (20-35%). This parameter change ensures the material is soft enough to allow complete removal without residue, while maintaining sufficient elasticity to protect fibre integrity during the removal process.
Data Source
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AI summary
It is disclosed an optical fibre unit for air-blown installations comprising: a number of optical fibres, an inner layer substantially completely embedding said optical fibres, and an outer layer radially external to the inner layer, wherein said inner layer has a tensile strength of from 0.1 MPa to 1 MPa, and an elongation at break of from % to 80%.