Fire Resistant Cable System with Phase-Change Cooling Conduit
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Solution Overview
Problem
Existing fire resistant and flame retardant cable systems face issues such as the release of toxic gases, mechanical weakness, high cost, and complexity in installation, particularly when trying to retrofit non-fire resistant cables, and the use of expensive materials like mica which complicates manufacturing and increases costs.
Innovation Solution
A fire resistant and flame retardant cable system is designed with a conduit containing a fluid with a boiling temperature lower than the cable's burning point, equipped with pressure relief valves to release vaporized fluid and maintain the temperature at the boiling point, thereby delaying the burning of the cable layers, and this system can be easily installed and maintained without the need for hydraulic circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fire resistant and flame retardant materials (PVC, polymers with additives, ceramifying materials, mica) are used in cables, then fire resistance and flame retardant properties are improved, but toxic gas release, mechanical weakness, high cost, and manufacturing complexity increase
Solution Approach 1:
A water-filled conduit is introduced as an intermediary cooling system between the cable and the fire environment. The water absorbs heat from the cable through thermal conduction, preventing the cable from reaching combustion temperatures, thereby eliminating toxic gas release without modifying the cable's original fire-resistant materials
Solution Approach 2:
The water in the conduit undergoes phase transition from liquid to vapor when exposed to fire heat, absorbing large amounts of latent heat in the process. This phase change effectively cools the cable, preventing it from reaching the temperature required for toxic gas emission while maintaining structural integrity
2Reliability
If fire resistant and flame retardant materials (PVC, polymers with additives) are used in cables, then fire resistance is improved, but mechanical strength deteriorates due to additive incorporation
Solution Approach 1:
The water-filled conduit acts as a thermal barrier that prevents the cable from reaching temperatures where material degradation occurs. By maintaining the cable temperature below combustion and degradation points, the original mechanical strength of the cable materials is preserved without requiring fire-resistant additives that would weaken the structure
3Reliability
If ceramifying materials and mica are used in cables, then fire resistance is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The water-filled conduit serves as a simple,低成本 cooling system that provides fire protection without requiring expensive ceramifying materials or mica. The system consists of a basic conduit structure filled with water, which can be easily manufactured and installed, eliminating the need for complex fire-resistant material processing
Solution Approach 2:
The phase transition of water from liquid to vapor provides efficient fire protection through latent heat absorption. This natural physical phenomenon replaces the need for expensive fire-resistant materials like ceramifying substances and mica, significantly reducing manufacturing costs while maintaining effective fire resistance
4Reliability
If hydraulic circuits with refrigerant circulation are used for cable cooling, then fire resistance is improved, but device complexity and installation difficulty increase
Solution Approach 1:
The complex hydraulic circuit with refrigerant circulation, condensating means, and multiple conduits is removed and replaced by a simple water-filled conduit. Only the essential cooling function is retained, eliminating unnecessary complexity while maintaining fire resistance through the phase transition of water
Solution Approach 2:
The phase transition of water from liquid to vapor provides passive cooling without requiring active refrigerant circulation systems. This natural phase change process eliminates the need for complex hydraulic circuits, pumps, and condensating equipment, resulting in a simple, easy-to-install system that maintains effective fire protection
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
This solution effectively delays the burning of cable layers, reduces flame propagation, and simplifies installation by eliminating the need for hydraulic circuits, while also reducing environmental pollution from toxic gas release during fires.
Implementation Method 1
a conduit provided along a portion of the cable length and in thermal contact thereto
Implementation Method 2
having a boiling temperature lower than the burning temperature of the cable
Implementation Method 3
maintain the temperature at the boiling point, thereby delaying the burning of the cable layers
Implementation Method 4
at least one pressure relief valve connected to the conduit
Data Source
Figure 1~2
Figure 3~4
AI summary
It is disclosed a fire resistant and flame retardant cable system comprising a cable, a conduit provided along a portion of the cable length and in thermal contact thereto; a fluid contained in the conduit and having a boiling temperature lower than the burning temperature of the cable; and at least one pressure relief valve connected to the conduit. When a portion of the cable is exposed to a fire, the temperature of the fluid locally increases and, as it reaches the boiling temperature, the fluid boils thereby producing a vapor. The vapor propagates through the conduit and is released through the pressure relief valve. The ebullience and release of the vapor through the valve delays the cable heating and burning.