High Temperature Fire Sleeve Composite Design
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Solution Overview
Problem
Current flexible hoses for high-temperature environments, such as aircraft engines, face issues with temperature degradation, flammability, and limited durability, particularly when exposed to fires, as existing fire-resistant materials like silicone rubber sleeves fail to provide long-term protection and resistance to chemicals and abrasion.
Innovation Solution
A flexible hose design featuring a core tube surrounded by a fibrous insulating layer, a metal chemical resistant layer, and a vented jacket made of corrosion-resistant materials like stainless steel or nickel alloys, which provides non-ablative performance up to 1090°C (2000°F) for extended periods and maintains mechanical integrity at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicone rubber fire sleeves are used to protect hoses from fire, then fire resistance is improved, but the material ablates, shrinks, and cracks at extremely high temperatures leading to failure around 14,000 hours
Solution Approach 1:
The patent employs a multi-layer composite construction consisting of an inner hose assembly, insulating layer (such as ceramic fiber or silica), metal fire barrier layer (stainless steel or nickel alloy), and outer protective cover. This composite structure combines the fire resistance of metal barriers with the thermal insulation properties of ceramic materials, preventing the heat from directly degrading the silicone rubber while maintaining structural integrity over extended periods at high temperatures.
2Temperature
If metal tube fire sleeves are used above 232°C, then short-term protection is provided, but protection duration is limited and not suitable for extended high temperature exposure
Solution Approach 1:
The patent introduces an insulating layer made of ceramic fiber or silica as an intermediary between the metal fire barrier and the inner hose assembly. This intermediary layer provides thermal insulation that reduces heat transfer to the hose while allowing the metal barrier to withstand high temperatures. The combination enables extended protection duration by preventing thermal degradation of the hose materials over prolonged exposure to temperatures above 232°C.
3Temperature
If fluid flow is maintained through the hose during fire, then the hose is kept cool, but flammable fluids may feed or intensify the fire
Solution Approach 1:
The patent's robust fire protection system with metal barriers and ceramic insulation converts the potential harm of maintaining fluid flow (feeding the fire) into a benefit by enabling the system to withstand fire exposure without requiring fluid flow for cooling. The insulating and fire barrier layers provide such effective thermal protection that the hose can withstand fire temperatures even with reduced or stopped fluid flow, preventing fire intensification while maintaining hose integrity.
4Reliability
If silicone rubber fire sleeves are used, then fire protection is provided, but resistance to oil, fuel, and chemical attack is not achieved
Solution Approach 1:
The patent uses a composite structure where the metal fire barrier layer (stainless steel or nickel alloy) and outer protective cover provide resistance to oil, fuel, and chemical attack, while the insulating layer and inner hose assembly provide fire protection. This multi-material composite approach allows each layer to specialize in resisting specific harmful factors, achieving both fire protection and chemical resistance simultaneously.
5Reliability
If silicone rubber fire sleeves are used, then fire protection is provided, but resistance to chafing and abrasion is not achieved
Solution Approach 1:
The patent incorporates an outer protective cover made of abrasion-resistant material as part of the composite fire sleeve structure. This outer layer provides mechanical protection against chafing and abrasion, while the underlying metal fire barrier and insulating layers maintain fire protection. The composite construction allows each material to perform its specialized function.
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 hose achieves high temperature resistance, fireproof performance, and chemical resistance, allowing it to operate effectively at temperatures up to 460°C (860°F) for extended periods while maintaining structural integrity and preventing fluid leakage during fires.
Implementation Method 1
an insulating layer surrounding a core tube
Implementation Method 2
a vented jacket surrounding the cover layer
Data Source
Figure 1
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AI summary
A flexible hose (100) for conveying fluids and suitable for high temperature environments, the hose (100) comprising a core tube (110), a thermal insulating layer (130) surrounding the core tube (110), a metal layer surrounding the thermal insulating layer (130), and a vented jacket (150) surrounding the cover layer (140). The thermal insulating layer (130) may be a fibrous material such as a silica fibre. The metal layer may also be a chemical resistant layer and be thermally stable up to at least about 288°C (550°F). The vented jacket (150) may be a wire braid having interstices therein and formed from a corrosion resistant material.