Transfer Tube Sealing Assembly for Leakage and Thermal Deflection

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Solution Overview

Problem

Bleed air systems in gas turbine engines face challenges in minimizing fluid leakage and accommodating thermal and mechanical deformations, which affect the reliability and longevity of fluid transfer tubing.

Innovation Solution

A transfer tube assembly with a metallic base member and attachment ring, featuring a wear sleeve and thermal insulation sleeve, along with split rings and O-rings, is designed to reduce leakage and allow for thermal and vibratory movement, ensuring secure attachment and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid sealing structure is used to prevent fluid leakage, then sealing effectiveness is improved, but the structure cannot accommodate thermal and mechanical deformations, leading to material fatigue and reduced reliability

Engineering Contradiction:
Improvesealing effectivenessVSAvoidaccommodation of thermal and mechanical deformations
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The sealing assembly incorporates a flexible membrane that can dynamically deform to accommodate thermal expansion and mechanical vibrations while maintaining the seal. The membrane's flexibility allows it to adapt to dimensional changes in the transfer tube and casing, preventing material fatigue from rigid constraints.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A flexible membrane forms the core sealing element, providing both sealing effectiveness and adaptability. The thin film structure can elastically deform with thermal and mechanical changes while maintaining contact with sealing surfaces, resolving the contradiction between rigid sealing and flexible accommodation.

Inventive Principle:
Principle #30Flexible shells and thin films

2Adaptability or versatility

If a flexible sealing structure is used to accommodate thermal and mechanical deformations, then adaptability is improved, but fluid leakage increases due to compromised sealing effectiveness

Engineering Contradiction:
Improveaccommodation of thermal and mechanical deformationsVSAvoidsealing effectiveness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The flexible membrane provides adaptability while maintaining sealing through its continuous, elastic nature. The membrane deforms with thermal and mechanical changes but maintains contact with sealing surfaces, preventing fluid leakage despite the flexibility.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sealing assembly combines the flexible membrane with rigid support structures (base member and attachment ring). This composite structure provides both the flexibility needed for deformation accommodation and the rigidity required for effective sealing, resolving the contradiction between adaptability and sealing effectiveness.

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If the transfer tube is rigidly fixed to the casing, then structural stability is improved, but thermal expansion and vibratory movements cause material fatigue and reduced longevity

Engineering Contradiction:
Improvestructural stabilityVSAvoidlongevity of fluid transfer tubing
Core Design Contradiction:
Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The sealing assembly allows the transfer tube to dynamically move relative to the casing through elastic deformation of the membrane and controlled movement within the sealing chamber. This dynamic capability accommodates thermal expansion and vibrations without compromising structural stability, preventing material fatigue and extending component longevity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sealing assembly acts as an intermediary between the rigid transfer tube and casing, absorbing thermal and vibratory movements. This intermediate layer protects both components from direct stress transmission, maintaining structural stability while extending the duration of action through fatigue reduction.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Duration of action of stationary object

If the transfer tube is allowed to move freely to accommodate deformations, then longevity is improved, but structural stability and secure attachment are compromised

Engineering Contradiction:
Improvelongevity of fluid transfer tubingVSAvoidstructural stability
Core Design Contradiction:
Duration of action of stationary objectVSStability of the object's composition

Solution Approach 1:

The sealing assembly provides controlled movement rather than free movement. The membrane and sealing chamber allow necessary deformations while constraining the transfer tube within defined limits, maintaining both longevity through fatigue reduction and structural stability through controlled positioning.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sealing assembly serves as an intermediary that secures the transfer tube to the casing while accommodating movements. This intermediate structure provides stable attachment points while allowing the tube to deform within the sealing chamber, balancing longevity and structural stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 assembly effectively minimizes fluid leakage and accommodates thermal and mechanical deformations, enhancing the reliability and longevity of fluid transfer components by allowing for axial, radial, and circumferential deflections without material fatigue.

Implementation Method 1

a thermal insulation sleeve is positioned between the fluid transfer tube and the annular ring

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

a wear sleeve is configured to surround the portion of the fluid transfer tube

Methodology Applied
Scientific EffectWear: Wear

Implementation Method 3

a wear sleeve is positioned between the thermal insulation sleeve and the annular ring

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3597869B1Sealing configuration for a transfer tube assembly to reduce air leakage
Publication Date: 2021.11.10 RTX CORP
  • EP3597869B1 patent drawingFigure 1A~1B
  • EP3597869B1 patent drawingFigure 2A
  • EP3597869B1 patent drawingFigure 2B

AI summary

A seal assembly (230) for a fluid transfer tube (250) in a gas turbine engine (100) includes a base member (232) having a first side configured to mate with a casing (224) and a second side opposite the first side, an annular ring (260, 262) configured to mate with the second side of the base member (232) and to surround a portion of the fluid transfer tube (250), a first O-ring disposed between the annular ring (260, 262) and the fluid transfer tube (250), a second O-ring disposed between the base member (232) and the annular ring (260, 262), and an attachment ring (236) configured to secure the annular ring (260, 262) and the base member (232) to the casing (224).