Elastomeric Corrosion Plug for Turbomachine Stator Blade Fixing Holes

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Solution Overview

Problem

Corrosion at the fixing holes of stator blade roots in turbomachines due to stagnant water, with existing solutions either weakening the blade root or increasing assembly and maintenance times, and previous solutions either requiring modifications or being prone to water infiltration.

Innovation Solution

A plug made of elastically deformable material with a cylindrical shape and blind holes to prevent water infiltration and eliminate beads, allowing easy installation and removal without modifying the orifice or cup, ensuring secure fit and longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the upper parts of fixing holes are filled with RTV silicone compound, then corrosion is prevented, but assembly duration and dismantling time increase significantly

Engineering Contradiction:
Improvecorrosion preventionVSAvoidassembly and dismantling time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent employs a disposable plug made of elastomeric material that is inserted into the fixing hole to prevent corrosion. The plug is designed to be easily removable and replaceable, eliminating the time-consuming process of removing and cleaning silicone compound while maintaining effective corrosion protection throughout the service life of the blade.

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

2Reliability

If shutters with plugs and cups are used to fill fixing holes, then corrosion is prevented, but the structure becomes complex and water infiltration may occur

Engineering Contradiction:
Improvecorrosion preventionVSAvoidshutter structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of corrosion prevention from the complex shutter-cup-plug assembly and implements it through a single, simple elastomeric plug inserted directly into the fixing hole. This eliminates the need for cups, pins, slots, and other components, significantly reducing structural complexity while maintaining effective water infiltration prevention.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses an elastomeric plug with flexible material properties that can deform to fit the fixing hole geometry and create an effective seal. The flexibility of the elastomeric material allows the plug to conform to the hole shape and prevent water infiltration without requiring the rigid, complex shutter structure of previous solutions.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If fixing holes are reform ed and sockets fitted, then corrosion is temporarily prevented, but blade root strength decreases and service life is reduced

Engineering Contradiction:
Improvecorrosion preventionVSAvoidblade root strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies a protective coating to the fixing holes during manufacturing before assembly, and inserts corrosion prevention plugs during normal maintenance rather than requiring blade removal and rework. This preliminary protection and proactive maintenance approach prevents corrosion before it weakens the blade root, eliminating the need for strength-reducing reforms and socket fittings.

Inventive Principle:
Principle #10Preliminary action

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

Prevents corrosion by completely obstructing the fixing orifice, is easy to install and remove, and does not disengage during turbomachine operation, thus extending the life of the screwing means and the blade root.

Implementation Method 1

The plug (50) is made of an elastically deformable material, and has a diameter at rest and an elasticity allowing it to obstruct and to be held in the fixing orifice by elastic deformation

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3253951B1Corrosion protection plug for filling an attachment opening, and system including said plug
Publication Date: 2020.10.21 SAFRAN AIRCRAFT ENGINES SAS
  • EP3253951B1 patent drawingFigure 1
  • EP3253951B1 patent drawingFigure 2a~2b
  • EP3253951B1 patent drawingFigure 3

AI summary

The invention relates to a plug (50) for preventing corrosion of an attachment opening (22). Said plug comprises: - a bottom surface (51) including an opening (60) for receiving a head (27) of a tightening means (23); - a top surface (52); and - a substantially cylindrical side wall (53) extending between the bottom surface (51) and the top surface (52). Said side wall (53) includes a first side area (66) characterized in that: - the plug (50) is formed of a elastically deformable material and has a diameter (Db) at rest and resiliency enabling said plug to block, and be held in, a top portion (22b) of the attachment opening (22) via resilient change in shape; and - the top surface (52) comprises at least one first blind hole (64, 94), the shape of which is such that, when the plug (50) is subjected to an elastic deformation that causes a ridge to appear between the top surface (52) and the first side area (66) of the plug (50), said ridge is removed by elastic deformation of said blind hole (64, 94).