Ceramifiable Cable Fire Protection with Expansion-Constrained Ceramic Layer
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Solution Overview
Problem
Current hydrocarbon fire protection solutions for cables, such as those used in the oil, gas, and petroleum industry, allow gas and liquid migration through ceramifiable compounds with cavities, making them inadequate for certain applications and resulting in inadequate fire resistance and potential loss of protection due to material expansion.
Innovation Solution
A fire protection arrangement for low-voltage or medium-voltage electrical cables featuring a halogen-free, ceramifiable compound with a polymer matrix that transforms into a ceramic material, combined with a fibre glass tape allowing expansion and a mechanical outer cover, providing enhanced fire resistance and preventing protection loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramifiable compound with cavities is used for fire protection, then fire resistance is improved, but gas and liquid migration through the conduits occurs making the protection inadequate
Solution Approach 1:
The patent uses a ceramifiable compound that forms a porous ceramic structure upon heating. This porous structure allows controlled expansion while maintaining integrity to prevent gas and liquid migration. The porosity is created through the ceramification process itself rather than pre-formed cavities, resolving the contradiction between fire resistance and migration prevention.
Solution Approach 2:
The patent employs a composite structure consisting of a ceramifiable compound combined with a refractory cementitious matrix. This composite material provides both fire resistance through ceramic transformation and structural integrity to prevent migration of gases and liquids, while allowing controlled expansion during the ceramification process.
2Reliability
If a ceramifiable compound with large cavities is used, then fire protection expansion is improved, but the extrusion process becomes more complex
Solution Approach 1:
The patent changes the physical and chemical parameters of the compound by incorporating ceramifiable materials that undergo transformation when exposed to fire. The compound is extruded in a manageable semi-rigid state and then transforms in-situ during fire exposure, achieving expansion and ceramic protection without complex extrusion of pre-formed cavity structures.
Solution Approach 2:
The patent applies a refractory cementitious coating to the compound before extrusion or incorporates it into the compound matrix in advance. This preliminary preparation ensures proper expansion characteristics during fire exposure while maintaining simple extrusion processes for the semi-rigid compound material.
3Ease of manufacture
If a continuous solid layer of ceramifiable material is extruded, then manufacturing simplicity is improved, but gas and liquid migration prevention may be compromised
Solution Approach 1:
The patent utilizes phase transition of the ceramifiable compound from a semi-rigid extrudable state to a ceramic solid state upon heating. This phase transition creates a dense, non-porous ceramic structure that effectively prevents gas and liquid migration, while allowing simple continuous extrusion of the compound in its softer, more workable state.
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 significantly improves fire resistance by allowing the ceramic material to expand without breaking, maintaining protection for longer durations and preventing gas and liquid migration, while simplifying the extrusion process and ensuring mechanical stability and low smoke emission.
Implementation Method 1
a layer of ceramifiable coating... which when subjected to fire, transforms into a ceramic material that protects the inner part of the cable
Implementation Method 2
the compound is characterized in that it has a polymer matrix with a fireproof filling material, which when subjected to fire, transforms into a ceramic material
Implementation Method 3
During this transformation into a ceramic material, the material increases in volume by up to 200%
Implementation Method 4
it increases in volume by up to 200%, it almost does not emit any type of smoke
Implementation Method 5
a fibre glass tape is applied with orifices that acts as a fire barrier. The function of this tape is to avoid that the ceramic material falls off during exposure to fire
Implementation Method 6
Good thermal conductivity in virgin state. When the compound is extruded over a cable the heat does not accumulate inside the cable it is protecting. Said accumulation is avoided since the compound allows the heat to be transported through it towards the open air
Implementation Method 7
Good thermal insulation above 200°C
Implementation Method 8
When the compound reaches a temperature between 750-800°C, pyrolysis occurs of the polymer binders, which generates a 'solid' layer of microporous ceramic
Implementation Method 9
Low smoke emission during combustion. The reading of the clear light beam measured according to ASTM E662 is of 70% and 94% for irradiation and open flame, respectively
Data Source
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AI summary
The invention consists of a fire protection arrangement for low-voltage or medium-voltage instrumentation cables, which is disposed over a cable core, comprising a first layer of an extruded ceramifiable thermoplastic compound over the core of the cable, a second layer that acts as a fire barrier disposed over the first layer retaining same on the core of the cable and adapted to allow the expansion of the ceramifiable compound, and a third extruded plastic solid layer over the second layer that acts as fire barrier without actively protecting against fire generated by hydrocarbons. The invention allows the cable to be used safely in fixed installations located in areas where the resistance to fire generated by hydrocarbons is vital.