Single Seal Tube Assembly for Vane Pump Leakage Control

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Solution Overview

Problem

Labyrinth seals in aircraft pump systems are prone to leakage and efficiency loss due to thermal growth, misalignment, and contamination, leading to seizure and reduced pump performance.

Innovation Solution

A single seal tube assembly with internal O-rings and backup rings is introduced, replacing the labyrinth seals, which is made of leaded bronze and securely coupled to the vane pumps to inhibit fluid flow and maintain axial pressure balance, allowing for increased robustness and extended service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If tight clearance is used in labyrinth seals to limit leakage, then leakage is reduced, but the seals become prone to seizure due to thermal growth, misalignment, and contamination

Engineering Contradiction:

ImproveleakageVSAvoidseal seizure

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The seal assembly is divided into multiple functional components: a seal tube with O-rings for primary sealing, backup rings for support, and labyrinth seals for secondary sealing. This segmentation allows each component to perform its specific function without the others suffering from the drawbacks of tight clearances

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The seal tube with O-rings acts as an intermediary element between the high-pressure and low-pressure regions, providing a reliable seal that prevents the direct contact and thermal growth issues experienced by traditional labyrinth seals with tight clearances

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of energy

If tight clearance is used in labyrinth seals to limit leakage, then leakage is reduced, but misalignment and axial movement cause the seals to touch and gall

Engineering Contradiction:

ImproveleakageVSAvoidmisalignment tolerance

Core Design Contradiction:

Loss of energyVSEase of operation

Solution Approach 1:

The invention changes the clearance parameter from tight (in labyrinth seals) to loose (in the seal tube assembly), allowing misalignment and axial movement without galling. The O-rings maintain sealing effectiveness despite parameter variations

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If tight clearance is used in labyrinth seals to limit leakage, then leakage is reduced, but contamination particles cause parts to touch and gall

Engineering Contradiction:

ImproveleakageVSAvoidcontamination sensitivity

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The O-rings in the seal tube assembly act as flexible sealing elements that can deform to accommodate contamination particles without causing galling, unlike the rigid tight-clearance labyrinth seals

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentEP3343041B1Vane pump seal

Publication Date: 2022.02.09 HAMILTON SUNDSTRAND CORP

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AI summary

A seal tube assembly of a pump system is provided. The seal tube assembly includes a single seal tube (41) having a first axial end (410) sealably coupled to a first vane pump (12) and a second axial end (411) sealably coupled to a second vane pump (13). The single seal tube includes transverse contact surfaces (412, 413) at the first axial end and transverse contact surfaces (414, 415) at the second axial end. The single seal tube is formed to define a first seal tube cavity (417) at the first axial end and a second seal tube cavity at the second axial end.