Fire-Resistant Cable Shielding With Transfer Ports for Pressure Relief

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Solution Overview

Problem

Existing fire-resistant cables fail to maintain operability for an extended period during a fire without additional effort or expenditure, and their manufacturing processes and materials are not applicable to various cable structures.

Innovation Solution

A fire-resistant cable design featuring a core surrounded by a shielding layer with transfer ports that allow the release of gaseous and non-gaseous materials emitted during a fire, preventing pressure buildup and mechanical destruction, while maintaining fire resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cable structures with tightly wrapped insulation tapes are used, then fire resistance is maintained for a certain period, but the cable suffers mechanical destruction from pressure buildup during fire

Engineering Contradiction:
Improvefire resistance durationVSAvoidmechanical stability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The shielding layer is designed with transfer ports (perforations, holes, slits, or zones of weakening) that create a controlled porous structure. This allows gaseous and non-gaseous materials to escape from the cable core during fire, preventing pressure buildup that would otherwise cause mechanical destruction of the cable structure.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The shielding layer is segmented into multiple functional zones: fire-resistant material regions and transfer port regions. This segmentation allows the structure to simultaneously provide fire protection and pressure relief, resolving the contradiction between maintaining fire resistance and preventing mechanical failure.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If the cable core is completely enclosed by fire-resistant layers, then fire protection is maximized, but pressure buildup causes premature cable destruction

Engineering Contradiction:
Improvefire protectionVSAvoidoperability duration
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The transfer ports act as intermediary channels between the enclosed cable core and the external environment. They allow controlled passage of fire-induced gases and materials, mediating between the need for complete enclosure (fire protection) and the need for pressure relief (operability duration).

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful pressure buildup from fire emissions is converted into a beneficial controlled release mechanism. The transfer ports transform the potentially destructive pressure into a controlled outflow, extending cable operability during fire conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If transfer ports are added to the shielding layer, then pressure relief and extended operability are achieved, but manufacturing complexity increases

Engineering Contradiction:
Improveoperability durationVSAvoidshielding layer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The transfer ports are designed with specific parameter ranges (size, distribution, shape) that can be optimized to achieve pressure relief with minimal impact on fire resistance. By controlling these parameters, the manufacturing complexity is managed while maintaining the reliability benefits.

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 design extends the operability of fire-resistant cables by preventing premature destruction due to pressure buildup, ensuring the cable remains functional for a longer duration by allowing the release of emitted materials through strategically designed ports.

Implementation Method 1

transfer ports that allow transfer of gaseous and/or non-gaseous material emitted by the core of the fire-resistant cable

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3886121B1Fire-resistant cable
Publication Date: 2026.05.06 LAPP ENG
  • EP3886121B1 patent drawingFigure 1a~1c
  • EP3886121B1 patent drawingFigure 2

AI summary

The invention relates to a fire-resistant cable (10) having a cable longitudinal axis (cx), comprising - at least one conductor or group of conductors (1; 1A, 1B, 1C, 1D); - at least one protection layer (2) formed around and enclosing said conductor or group of conductors (1; 1A, 1B, 1C, 1D); - an inner jacket layer (3) formed around and enclosing said at least one protection layer (2); which at least one conductor or group of conductors (1; 1A, 1B, 1C, ID), the at least one protection layer (2) and the inner jacket layer (3) forming the core (100) of the fire-resistant cable (10), which is surrounded by an outer jacket layer (7). According to the invention between the core (100) of the fire-resistant cable (10) and the outer jacket layer (7) a shielding layer (4) is formed around the core (100) of the fire-resistant cable (10), which shielding layer (4) is provided with transfer ports (40) that allow transfer of gaseous and/or non-gaseous material emitted by the core (100) of the fire-resistant cable (10).