Multilayer Shielded Cable With Intumescent Fire Barrier
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Solution Overview
Problem
Data center communication cable assemblies require shielding to prevent electromagnetic interference while also needing to be made from low Halogen content materials that exhibit flammability resistance and physical flexibility without compromising signal transmission performance.
Innovation Solution
A shielded electrical cable design featuring multiple conductor sets with insulated and uninsulated drain grounding wires, electrically conductive shielding films, and a multilayer third shielding film with an intumescent layer, wrapped around the conductor sets and enclosed in an insulative braided sleeve, which provides effective electromagnetic shielding and fire resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional shielding materials are used to contain electromagnetic fields, then electromagnetic shielding performance is improved, but flammability resistance deteriorates due to high Halogen content materials
Solution Approach 1:
The patent employs a composite shielding structure consisting of multiple layers: an inner aluminum shielding layer, a polymeric jacket layer, and an outer metallic braid shielding layer. This composite approach allows each layer to contribute different properties - the aluminum provides electromagnetic shielding, the polymeric jacket provides flexibility and fire resistance, and the braid provides additional shielding and mechanical strength. The combination resolves the contradiction by achieving effective electromagnetic interference containment without relying solely on traditional high-Halogen shielding materials.
Solution Approach 2:
The patent modifies the shielding structure by transitioning from a single-layer traditional shield to a multi-layer configuration with changed material parameters. The inner aluminum layer uses thin-film deposition techniques to achieve optimal shielding effectiveness with minimal material, while the outer braid uses configurable coverage percentages (e.g., 85-95% coverage) to balance shielding performance with flexibility and fire resistance requirements.
2Reliability
If low Halogen content materials are used to improve flammability resistance, then fire safety is improved, but electromagnetic shielding performance may deteriorate
Solution Approach 1:
The patent uses a composite shielding system where the polymeric jacket layer (made from low-Halogen fire-resistant materials) works in conjunction with metallic shielding layers. The jacket provides fire safety while the aluminum and braid layers provide electromagnetic shielding, allowing the system to achieve both flammability resistance and shielding performance simultaneously rather than compromising one for the other.
Solution Approach 2:
The polymeric jacket layer serves multiple functions: it provides fire resistance through low-Halogen content, maintains physical flexibility for cable bending and installation, offers mechanical protection to inner conductors, and contributes to the overall shielding effectiveness when combined with the metallic layers. This multi-functionality resolves the contradiction by making the fire-resistant material an active participant in maintaining electromagnetic shielding rather than merely a protective outer layer.
3Object-affected harmful factors
If thick shielding layers are used to enhance electromagnetic containment, then shielding effectiveness is improved, but physical flexibility deteriorates
Solution Approach 1:
The patent divides the shielding function into separate layers: a thin inner aluminum layer for primary electromagnetic containment, a flexible polymeric jacket for physical flexibility and fire resistance, and an outer braid layer for additional shielding and mechanical protection. This segmentation allows each layer to be optimized for its specific function - the aluminum layer can be thin since it's supported by the flexible jacket, and the jacket itself provides the necessary physical flexibility that a single thick metallic layer would lack.
Solution Approach 2:
The patent employs thin-film aluminum deposition on the inner conductor and a flexible polymeric jacket that can bend and flex without compromising the shielding integrity. The thin aluminum layer provides sufficient electromagnetic containment when properly grounded, while the flexible polymer jacket maintains physical flexibility for cable installation and movement, resolving the contradiction between shielding effectiveness and flexibility.
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 contains electromagnetic fields, maintains signal transmission performance, and offers enhanced flammability resistance and physical flexibility, addressing the need for low Halogen content materials in data center communication cables.
Implementation Method 1
an intumescent layer disposed on the substrate layer including an intumescent material
Implementation Method 2
electrically conductive first and second shielding films disposed on opposite corresponding first and second sides of the conductor set
Data Source
AI summary
A shielded electrical cable is disclosed and includes a plurality of separate individual conductor sets. Each conductor set extends along a length of the cable and includes two or more insulated conductors, at least one uninsulated drain grounding wire, and electrically conductive first and second shielding films. The first and second shielding films include cover portions and pinched portions. Each pinched portion includes an edge extending along the length of the cable. An electrically conductive multilayer third shielding film is wrapped at least once around the plurality of separate individual conductor sets along the length of the cable and includes a substrate layer, an electrically conductive third shielding layer disposed on the substrate layer, and an intumescent layer disposed on the substrate layer and comprising an intumescent material.