Passive Filter Assembly Centrifugal Separation for Gearbox

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Solution Overview

Problem

Conventional gearbox and engine filters fail to effectively manage larger particulates such as coked fuel/oil, leading to increased pressure drop and reduced filter life.

Innovation Solution

A passive filter assembly design that utilizes a filter bowl with a fluid inlet configured to induce swirl, a centrifuge mechanism to separate denser components, and a filter cap to collect and drain coked fluid, allowing cleaner fluid to pass through the filter element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional filters are used to filter small particulate, then filtering performance is maintained, but larger particulate causes backup within the filters leading to increased pressure drop and shortened filter life

Engineering Contradiction:
Improvefilter lifeVSAvoidpressure drop
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The filter system is segmented into two distinct functional zones: a centrifugal separation section for removing larger denser particulate before filtration, and a traditional filtration section for small particulate. This segmentation allows each zone to handle specific particle sizes, preventing backup and extending filter life.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The centrifugal separation performs preliminary action by removing larger denser particulate (coked fuel/oil) from the fluid stream before it enters the filter element. This pre-cleaning action prevents these larger particles from causing backup within the filter, thereby maintaining pressure differential and extending filter life.

Inventive Principle:
Principle #10Preliminary action

2Duration of action of moving object

If filter life is extended through centrifugal separation, then maintenance intervals are reduced, but device complexity increases due to additional components

Engineering Contradiction:
Improvefilter lifeVSAvoidfilter assembly structure
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The centrifugal separation functionality is merged with the filter housing structure. The bowl-shaped filter assembly integrates the centrifugal chamber, filter element support, and drainage system into a single unified component, avoiding the need for separate external centrifugal separators and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The filter assembly serves multiple functions simultaneously: it performs centrifugal separation of denser particulate, filters small particulate through the filter element, and collects drained fluid in the bowl. This multi-functionality eliminates the need for separate devices, reducing complexity while extending filter life.

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

3Reliability

If denser fluid components are collected in the filter cap, then filter performance is maintained, but drainage system complexity increases

Engineering Contradiction:
Improvefilter performanceVSAvoiddrainage system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The filter cap is positioned at the lowest point of the filter assembly, creating a gravitational equipotential zone where denser fluid components naturally accumulate. This gravitational positioning eliminates the need for complex pumping or forced drainage systems, as drainage occurs passively through gravity alone.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The drainage system is designed to be self-service through gravity-driven flow. The bowl shape and cap positioning automatically guide denser fluid components to the drainage point, requiring no external power source or complex control mechanisms, thus maintaining simplicity while ensuring continuous filter performance.

Inventive Principle:
Principle #25Self-service

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

Extends filter life, reduces maintenance intervals, minimizes down time, and maintains circuit pressure, thereby reducing costs and ensuring engine performance.

Implementation Method 1

The fluid inlet can be configured to cause the bulk fluid entering through the fluid inlet to swirl within the filter bowl to be centrifuged to separate one or more denser fluid components from the bulk fluid

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

The filter bowl can be shaped to allow the bulk fluid to swirl therein

Methodology Applied
Scientific EffectSwirl flow: Vortex Ring

Implementation Method 3

a filter cap disposed gravitationally below the filter bowl and configured to receive denser fluid components separated from a bulk fluid when the denser fluid components fall into the filter cap

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4574228A1Filter assembly
Publication Date: 2025.06.25 HAMILTON SUNDSTRAND CORP
  • EP4574228A1 patent drawingFigure 1
  • EP4574228A1 patent drawingFigure 2~3
  • EP4574228A1 patent drawingFigure 4~5

AI summary

A passive filter assembly (100) can include a filter bowl (102) configured to enclose a filter element (104) therein, a fluid inlet (106) in fluid communication with the filter bowl, a fluid outlet (108) in fluid communication with the filter bowl downstream of the fluid inlet, and a filter cap (110) disposed gravitationally below the filter bowl and configured to receive denser fluid components separated from a bulk fluid when the denser fluid components fall into the filter cap. The filter bowl can be shaped to allow the bulk fluid to swirl therein. The fluid inlet can be configured to cause the bulk fluid entering through the fluid inlet to swirl within the filter bowl to be centrifuged to separate one or more denser fluid components from the bulk fluid. The fluid outlet can be configured to receive a filtered flow downstream of a filter element.