Dual-Screen Oil Filtration With Pressure-Triggered Bypass

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Solution Overview

Problem

Existing oil filtration systems in gas turbine engines may experience clogging of last chance screens, leading to potential bearing starvation and failure due to severe upstream debris, which limits or cuts off oil flow to the bearing.

Innovation Solution

An oil filtration system with a dual screen arrangement and a bypass valve that allows oil to divert around a clogged first screen with finer mesh to a second screen with coarser mesh, ensuring continued oil supply to the bearing by opening a bypass when the first chamber volume reaches a threshold pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bypass valve is added to allow oil to divert around a clogged screen, then oil flow continuity is improved, but device complexity increases

Engineering Contradiction:
Improveoil flow continuityVSAvoidfiltration system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bypass valve is designed to operate automatically based on pressure differential without external control. When the first screen clogs and pressure increases, the valve self-activates to open the bypass pathway, eliminating the need for complex control systems while maintaining flow continuity.

Inventive Principle:
Principle #25Self-service

2Reliability

If dual screen arrangement with different mesh coarseness is used, then system reliability is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvesystem reliabilityVSAvoidscreen assembly complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The first screen and second screen are arranged in a nested configuration where the first screen is positioned within the second screen. This nesting approach simplifies assembly compared to separate mounting locations, as the screens can be installed together in a single operation while maintaining different mesh coarseness for reliable filtration.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

This configuration ensures continued operation of the system by maintaining oil flow to the bearing even when the first screen clogs, enhancing system reliability and safety by diverting oil through the second screen, thus preventing bearing starvation.

Implementation Method 1

the bypass valve disposed in a second position during a second pressure condition within the first chamber volume, the second position opening the bypass opening

Methodology Applied
Scientific EffectPressure: Pressure Increase

Data Source

PatentEP3412878B1Oil filtration system
Publication Date: 2023.07.26 RTX CORP
  • EP3412878B1 patent drawingFigure 1
  • EP3412878B1 patent drawingFigure 2
  • EP3412878B1 patent drawingFigure 3

AI summary

An oil filtration system (100) includes an oil chamber inlet (108). Also included is a first screen (114) defining a first chamber volume (112) that receives an oil flow (106) from the oil chamber inlet (108), the first screen (114) having a first mesh coarseness. Further included is a second screen (120) surrounding the first screen (114) to define a second chamber volume (121) surrounding the first chamber volume (112), the second screen (120) having a second mesh coarseness that is greater than the first mesh coarseness. Yet further included is at least one exit nozzle (110) having an exit cross-sectional area that is greater than or equal to a cross-sectional area of apertures of the second screen (120). Also included is a bypass valve (128) disposed in a first position during a first pressure condition within the first chamber volume (112) and in a second position during a second pressure condition within the first chamber volume (112).