Two-Piece Labyrinth Seal Ring for Bearing Housing Erosion

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Solution Overview

Problem

Erosion damage to the bearing support housing in aircraft cabin air compressors occurs due to foreign object particles bypassing the labyrinth seal and impacting the bearing support housing, shortening the service life of the compressor.

Innovation Solution

A seal assembly with a labyrinth seal and a seal support ring featuring a deflector ramp and circumferentially spaced teeth that deflect airflow radially inward and trap foreign object particles, reducing the impact on the bearing support housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a labyrinth seal is used between the impeller and bearing support housing, then sealing performance is improved, but foreign object particles can still bypass the seal and cause erosion damage to the bearing support housing

Engineering Contradiction:
Improvesealing performanceVSAvoiderosion damage to bearing support housing
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A seal support ring is introduced as an intermediary component between the labyrinth seal and the bearing support housing. This ring includes a deflector ramp that redirects airflow carrying foreign particles away from the bearing support housing, and circumferentially spaced teeth that trap particles, preventing them from reaching and eroding the housing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The deflector ramp utilizes the kinetic energy and direction of the leaking airflow (which carries foreign particles) to redirect this harmful flow away from the bearing support housing. The circumferentially spaced teeth convert the tangential component of the airflow into particle trapping, transforming the erosive flow into a particle collection mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If the seal support ring with deflector ramp and teeth is added, then protection against erosion is improved, but device complexity increases

Engineering Contradiction:
Improveerosion protectionVSAvoidseal assembly structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The seal support ring performs multiple functions simultaneously: it provides structural support for the labyrinth seal, redirects airflow away from the bearing support housing through the deflector ramp, and traps foreign particles using the circumferentially spaced teeth. This multi-functionality reduces the need for additional separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The deflector ramp and circumferentially spaced teeth are integrated into a single seal support ring component, combining multiple protective functions into one unified structure that is installed as a single unit between the impeller and bearing support housing.

Inventive Principle:
Principle #5Merging (Combining)

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 solution effectively reduces erosion of the bearing support housing, extending the service life of the compressor by diverting airflow and trapping foreign particles, and is retrofittable to existing compressors without modifying surrounding components.

Implementation Method 1

The deflector ramp is configured to turn an airflow leaking through the seal interface radially inwardly toward the central axis

Methodology Applied
Scientific EffectFluid deflection:

Implementation Method 2

a plurality of circumferentially spaced teeth configured to diffuse a tangential component of the airflow

Methodology Applied
Scientific EffectFlow diffusion:

Implementation Method 3

the plurality of circumferentially spaced teeth trap foreign object particles from the airflow between adjacent teeth of the circumferentially spaced teeth

Methodology Applied
Scientific EffectParticle trapping:

Data Source

PatentEP3992467A1Erosion mitigating two piece labyrinth seal mating ring
Publication Date: 2022.05.04 HAMILTON SUNDSTRAND CORP
  • EP3992467A1 patent drawingFigure 1
  • EP3992467A1 patent drawingFigure 2
  • EP3992467A1 patent drawingFigure 3

AI summary

A compressor assembly includes an impeller (14) rotatable about a central axis, and a seal assembly. The seal assembly includes a labyrinth seal (32) defining a seal interface (52) with a sealing element of the impeller, and a seal support ring into which the labyrinth seal is installed. The seal support includes a deflector ramp (54) fluidly downstream of the seal interface. The deflector ramp is configured to turn an airflow leaking through the seal interface radially inwardly toward the central axis.