Aircraft Engine Fire Seal Assembly for Thermal Movement Sealing

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Solution Overview

Problem

Existing fire seal assemblies for aircraft engines struggle to maintain a sufficient seal during engine movements and higher operating temperatures, particularly with larger, more powerful engines, which can lead to fire spread beyond the engine core.

Innovation Solution

The fire seal assembly incorporates L-caps with legs forming a u-shaped channel, P-seals, and end plugs to ensure a tight seal between the core service disconnect, engine firewall, and thrust reverser seals, allowing for flexible engagement and maintaining contact during engine movements and temperature variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing fire seal assemblies are used, then the structure is simple, but the seal effectiveness deteriorates during engine movements and at higher operating temperatures

Engineering Contradiction:
Improveseal effectivenessVSAvoidassembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fire seal assembly is divided into multiple functional segments: L-caps with legs forming a u-shaped channel, P-seals for sealing, and end plugs for closure. This segmentation allows each component to perform its specific function effectively, maintaining seal integrity during engine movements and temperature variations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The L-caps are designed with legs that can flex and adjust their position dynamically. This dynamic capability allows the assembly to maintain contact and sealing effectiveness during engine movements while accommodating thermal expansion and contraction at higher operating temperatures.

Inventive Principle:
Principle #15Dynamics

2Power

If larger, more powerful engines are used, then the power increases, but the fire seal reliability deteriorates due to increased movements and temperatures

Engineering Contradiction:
Improveengine powerVSAvoidfire seal containment
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The P-seals are implemented as flexible sealing elements that can deform and maintain contact under varying conditions. This flexibility allows the seals to remain effective despite the increased movements and thermal variations associated with larger, more powerful engines.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The assembly design accounts for parameter changes in temperature and movement range by using materials and structures that can adapt to these variations. The L-caps and P-seals are configured to maintain sealing pressure and contact across the expanded operational envelope required by high-power engines.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the fire seal maintains contact during engine movements, then the seal effectiveness improves, but the flexibility of the assembly deteriorates

Engineering Contradiction:
Improveseal consistencyVSAvoidengagement flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The L-caps are designed with inherent flexibility in their leg structures, allowing them to dynamically adjust their position and maintain contact during engine movements. This dynamic design provides both seal consistency and adaptation to varying engine positions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The P-seals function as flexible elements that can deform to maintain continuous contact with the firewall and thrust reverser seals. This flexibility ensures consistent sealing while accommodating the range of engine movements through elastic deformation.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP3750813B1Fire seal assemblies for aircraft engines
Publication Date: 2021.12.29 THE BOEING CO
  • EP3750813B1 patent drawingFigure 1
  • EP3750813B1 patent drawingFigure 2
  • EP3750813B1 patent drawingFigure 3

AI summary

Fire seal assemblies for aircraft engines are described herein. An example fire seal assembly includes a first L-cap having a first leg and a second leg extending outward from the first leg, and a second L-cap having a third leg and a fourth leg extending outward from the third leg. The first and third legs are to be coupled to a core service disconnect (CSD) on a pylon of an aircraft, and the second and fourth legs are to extend outward and engage sides of a firewall of an engine of the aircraft. The first seal assembly further includes a seal coupled to the first and third legs and disposed between the second and fourth legs, a first end plug disposed between a first end of the seal and the second leg, and a second end plug disposed between a second end of the seal and the fourth leg.