Counter-plate for Turbo Machine Corrosion and Stress

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Solution Overview

Problem

Turbomachines face issues with mechanical stress-induced degradation and galvanic corrosion between flanges, which are exacerbated by the use of multiple parts and complex assembly processes, leading to increased manufacturing and maintenance complexities.

Innovation Solution

A counter-plate with a first external surface made of a material that prevents galvanic corrosion, such as titanium alloy, and a second external surface with support surfaces for fastening means, which separates the flange from the fixing flange, reducing direct contact and corrosion while simplifying assembly and disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple parts (washers, bonded glass plies) are added to prevent galvanic corrosion and mechanical stress degradation, then corrosion protection is improved, but device complexity and manufacturing operations increase

Engineering Contradiction:
Improvecorrosion protectionVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple protective functions (galvanic corrosion prevention and mechanical stress relief) into a single counter-plate component. The counter-plate integrates the functions previously performed by separate washers and bonded glass plies, eliminating the need for multiple parts while maintaining comprehensive protection against both corrosion and mechanical degradation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The counter-plate is made from a composite material or a material with properties that simultaneously provide galvanic corrosion resistance and mechanical stress absorption. This allows a single component to deliver both protective functions without requiring layered structures of multiple materials.

Inventive Principle:
Principle #40Composite materials

2Strength

If the number of screws is increased to increase tightening zones, then mechanical stress distribution is improved, but device complexity and assembly operations increase

Engineering Contradiction:
Improvestress distributionVSAvoidnumber of fastening means
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent extracts the stress distribution function from the screw system and transfers it to the counter-plate structure. The counter-plate's geometry and material properties are designed to distribute mechanical stresses across multiple zones without requiring an increased number of fastening means, thereby maintaining simple assembly while achieving improved stress distribution.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If washers are added to distribute mechanical stresses, then stress distribution is improved, but ease of operation deteriorates due to washers not being held in position during assembly/disassembly

Engineering Contradiction:
Improvestress distributionVSAvoidassembly operations
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent merges the washer's stress distribution function directly into the counter-plate structure. The counter-plate is designed with features that inherently distribute mechanical stresses while being securely retained during assembly and disassembly operations, eliminating the operational difficulties associated with separate washer components.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If bonded glass plies are inserted to fight galvanic corrosion, then corrosion protection is improved, but manufacturing precision requirements increase due to complex bonding operations

Engineering Contradiction:
Improvecorrosion protectionVSAvoidbonding operation precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces complex bonded glass plies with a simpler counter-plate structure that provides equivalent or superior corrosion protection. The solution uses readily available materials and straightforward manufacturing processes, eliminating the need for precision bonding operations while maintaining effective galvanic corrosion protection.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 counter-plate effectively addresses both mechanical stress and galvanic corrosion issues with a single part, reducing manufacturing complexity and maintenance costs by preventing galvanic corrosion and enhancing assembly efficiency.

Implementation Method 1

the first external surface of the counter-plate being made of a material making it possible to prevent the galvanic corrosion likely to be created between the flange and the flange of attachment

Methodology Applied
Scientific EffectGalvanic corrosion prevention:

Implementation Method 2

the first outer surface separating the flange and the attachment flange

Methodology Applied
Scientific EffectPhysical separation:

Data Source

PatentEP2855860B1Turbo machine comprising a counter plate
Publication Date: 2018.11.21 SAFRAN AIRCRAFT ENGINES SAS
  • EP2855860B1 patent drawingFigure 1~2
  • EP2855860B1 patent drawingFigure 3~4
  • EP2855860B1 patent drawingFigure 5~6

AI summary

The invention relates to a counter plate (1) for a turbo machine, characterized in that: -the counter plate (1) comprises a first external surface (4) and a second external surface (5), which are substantially parallel; - the first external surface (4) of the counter plate (1) creates a continuous ring or continuous ring segment and comprises a first series (6) of holes through which fasteners (8) can pass; - the second external surface (5) of the counter plate (1) comprises a plurality of surfaces (51 52, 53 …) for supporting the heads (9) of fasteners, the support surfaces (51 52, 53 …) comprising a second series (7) of holes, positioned facing the first series (6) of holes, so that the fasteners (8) can pass through the holes (6, 7) in the counter plate (1).