Layered Aircraft Fire Seal for High-Temperature Interface Gaps

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Solution Overview

Problem

Aircraft fire seals face challenges in sealing dynamic structural interfaces due to manufacturing tolerances and temperature fluctuations, with existing solutions like rubber seals failing at high temperatures and metallic seals being difficult to install and costly.

Innovation Solution

A fire seal with an acute bend and engagement extensions formed from durable materials like stainless steel, featuring a layered structure with slots to enhance flexibility and durability, and a design that allows for easy installation and adaptation to curved surfaces, reducing manufacturing complexity and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If rubber seals are used to seal structural interfaces, then ease of installation is improved, but temperature resistance deteriorates at high operating temperatures

Engineering Contradiction:
Improveease of installationVSAvoidtemperature resistance
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The patent changes the material parameter from rubber to spring metal, which fundamentally alters the temperature resistance capability while maintaining flexibility. The spring metal material can withstand high temperatures in engine pylons while still providing the necessary sealing function through elastic deformation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fire seal combines spring metal with fireproof coating materials to create a composite structure that provides both high-temperature resistance and sealing capability. The coating layer protects the metal substrate from thermal damage while the metal provides structural integrity and elasticity.

Inventive Principle:
Principle #40Composite materials

2Temperature

If metallic feather seals are used to seal structural interfaces, then temperature resistance is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvetemperature resistanceVSAvoiddevice complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The fire seal is designed as a series of segmented fingers or leaves that can independently deflect and seal gaps. This segmentation simplifies the overall structure compared to traditional metallic feather seals while maintaining the ability to accommodate thermal expansion and manufacturing tolerances.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring metal fingers are designed to be dynamically flexible, allowing them to deflect and conform to the mating surface. This dynamic capability eliminates the need for complex adjustment mechanisms while ensuring reliable sealing under varying thermal and mechanical conditions.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If traditional sealing methods are used for dynamic structural interfaces, then manufacturing simplicity is maintained, but sealing effectiveness deteriorates due to manufacturing tolerances and temperature fluctuations

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidsealing effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the material parameter from rigid to elastic spring metal, which allows the seal to accommodate manufacturing tolerances and thermal expansion. This parameter change maintains manufacturing simplicity while dramatically improving sealing reliability under dynamic conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The spring metal fingers are pre-loaded with elastic energy that cushions against gaps caused by manufacturing tolerances and thermal expansion. This beforehand cushioning ensures continuous contact and reliable sealing without requiring precision manufacturing or complex adjustment mechanisms.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 fire seal effectively maintains a seal in high-temperature environments, is more flexible and compliant than traditional seals, reducing wear and tear, and can be fabricated as a single part for easier assembly and lower manufacturing costs.

Implementation Method 1

The fire seal may be spring-like in that it may be flexible and resilient

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The fire seal is more flexible and compliant than traditional seals, reducing wear and tear, and can be fabricated as a single part for easier assembly and lower manufacturing costs

Methodology Applied
Scientific EffectThermal resistance: Thermal Insulation

Data Source

PatentEP2957794B1Fire seal for an aircraft
Publication Date: 2023.08.09 THE BOEING CO
  • EP2957794B1 patent drawingFigure 1
  • EP2957794B1 patent drawingFigure 2
  • EP2957794B1 patent drawingFigure 3

AI summary

A seal including an acute bend (12) comprising a first end portion (18) and a second end portion (20); a first engagement extension (14) extending from said first end portion of said acute bend; and a second engagement extension (16) extending from said second end portion of said acute bend, wherein said second engagement extension is at an acute angle relative to said first engagement extension to define a partially enclosed volume (22) between said first engagement extension and said second engagement extension.