Fire Seal End Cap for Gap-Free Aircraft Firewall Interfaces

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Solution Overview

Problem

Aircraft engine fire barriers face challenges in sealing gaps between dynamic structural interfaces, such as the pylon and engine firewall, due to manufacturing tolerances and movement, which can lead to flame propagation.

Innovation Solution

A fire seal end cap with a cap portion and a plug portion, formed from fire-resistant materials, is positioned to bridge the interface between structural members, accommodating movement while maintaining a seal through a crossover seal with a bore, and optionally integrated with a thrust reverser fire seal to prevent gaps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a crossover seal is positioned between the engine firewall and the pylon to accommodate movement, then the seal can dynamically adapt to structural movement, but gaps may be created at the interface

Engineering Contradiction:

Improvedynamic adaptation to movementVSAvoidfire seal integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The end cap serves as an intermediary component that fills the gap between the crossover seal and the thrust reverser fire seal. It includes a seal surface that contacts the thrust reverser fire seal and a protruding portion that extends into the bore of the crossover seal, thereby mediating the interface and preventing gaps while allowing the crossover seal to maintain its dynamic adaptation function

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If structural interfaces are sealed with fireproof material to eliminate gaps, then flame propagation is prevented, but the seal must accommodate manufacturing tolerances and dynamic movement

Engineering Contradiction:

Improvefire barrier effectivenessVSAvoidaccommodation of movement and tolerances

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The end cap is formed from a flexible, fire-resistant material that can deform and conform to the varying positions of the engine firewall and pylon during movement. This flexible membrane approach allows the fire seal to maintain intimate contact and eliminate gaps while accommodating the dynamic movement and manufacturing tolerances of the structural interfaces

Inventive Principle:

Principle #30Flexible shells and thin films

3Ease of manufacture

If the thrust reverser fire seal is positioned to lie over the crossover seal, then seal routing is convenient, but gaps are created at the interface

Engineering Contradiction:

Improveseal routing convenienceVSAvoidfire seal continuity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The end cap acts as a mediator component that is positioned between the crossover seal and the thrust reverser fire seal. It provides a sealed interface that allows the thrust reverser fire seal to lie over the crossover seal routing while preventing gaps from forming at the interface, thus maintaining both the convenient seal routing and the fire seal continuity

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11117004B2Fire seal end cap and associated multi-member assembly and method

Publication Date: 2021.09.14 THE BOEING CO

AI summary

A fire seal end cap including a cap portion and a plug portion, wherein the plug portion protrudes from the cap portion, and wherein the cap portion and the plug portion are formed from a fire-resistant material.