Turbomachine Combustion Chamber Guide Device Weld Segmentation

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Solution Overview

Problem

Current guiding devices for spark plugs and fuel injectors in turbomachine combustion chambers face issues with weld overflows into the annular guide groove, leading to reduced movement and risk of jamming or breaking, and oversizing the device to compensate increases mass and obstructs ventilation.

Innovation Solution

The guiding device features two coaxial annular parts of the sleeve fixed by welding or brazing in areas outside the preferred movement path of the ring, allowing for reduced diameter and mass while preventing weld overflows from obstructing movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the two annular parts of the sleeve are fixed by weld beads extending over the entire circumference, then the structural strength and rigidity are improved, but the weld beads overflow into the annular guide groove and block the movement of the ring

Engineering Contradiction:
Improvestructural strengthVSAvoidmovement of the ring
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The continuous circumferential weld bead is segmented into discrete welding areas distributed around the circumference. This segmentation prevents weld overflow from blocking the entire guide groove, while still providing sufficient structural strength through multiple distributed weld points that collectively secure the annular parts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of uniform welding around the entire circumference, welding is applied locally at specific distributed areas. This local quality approach concentrates welding strength where structurally necessary while leaving other areas clear for ring movement, resolving the conflict between strength and operational freedom.

Inventive Principle:
Principle #3Local quality

2Reliability

If the sleeve is oversized to accommodate weld overflow and maintain clearance, then the risk of jamming is reduced, but the mass of the device increases and ventilation is obstructed

Engineering Contradiction:
Improverisk of jammingVSAvoidmass of the device
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

By segmenting the weld into discrete areas rather than a continuous bead, the weld overflow is confined to localized regions that do not compromise the guide groove clearance. This allows the sleeve to maintain its optimal dimensions without needing to be oversized, thus avoiding increased mass while still preventing jamming.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The welding is applied partially (only at discrete areas) rather than excessively (continuous circumferential weld). This partial action provides sufficient structural strength and prevents jamming without requiring the sleeve to be oversized, thereby avoiding unnecessary mass increase and ventilation obstruction.

Inventive Principle:
Principle #16Partial or excessive action

3Weight of moving object

If the diameter of the sleeve is reduced to decrease mass, then the ventilation is improved, but the clearance for ring movement is reduced and jamming risk increases

Engineering Contradiction:
Improvemass of the deviceVSAvoidjamming risk
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

Segmenting the weld into discrete areas prevents weld material from overflowing into the guide groove and consuming clearance space. This allows the sleeve diameter to be reduced for lower mass and improved ventilation while maintaining sufficient clearance for reliable ring movement, as the segmented weld does not encroach on the movement path.

Inventive Principle:
Principle #1Segmentation

4Ease of manufacture

If continuous circumferential welding is used, then the manufacturing process is simplified, but the welding operation is difficult to control and overflow cannot be prevented

Engineering Contradiction:
Improvewelding process simplicityVSAvoidweld overflow control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The welding process is segmented into discrete areas around the circumference rather than a continuous operation. This segmentation makes the welding operation easier to control, as each discrete area can be independently managed, and overflow is naturally limited to local regions that do not affect the entire guide groove.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Welding is applied with local quality at specific distributed areas rather than uniformly around the circumference. This approach improves manufacturing precision by allowing better control of weld parameters at each location and preventing overflow from propagating along the entire circumference, while still maintaining structural integrity.

Inventive Principle:
Principle #3Local quality

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 solution ensures smooth transverse movement of the ring without weld obstruction, reducing the risk of jamming and maintaining optimal ventilation, with a diameter reduction of approximately 2 mm compared to prior art.

Implementation Method 1

the two parts of the sleeve are fixed to one another by areas of welding or soldering

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

the two parts of the sleeve are fixed to one another by areas of welding or soldering

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP2071241B1Device for guiding an element in an orifice of a wall of a turbomachine combustion chamber
Publication Date: 2018.12.05 SAFRAN AIRCRAFT ENGINES SAS
  • EP2071241B1 patent drawingFigure 1
  • EP2071241B1 patent drawingFigure 2~4

AI summary

The device has a ring (150) and a bush (152) mounted coaxially one inside the other. The bush is fixed on an edge of an orifice of an external wall of a combustion chamber. The bush has annular parts i.e. annular piece (164) and a square shaped washer (166) fixed one on another by brazing or welding, where the parts define an annular groove. The ring is moved in a transverse direction. The annular parts are fixed together via welding or brazing zones (180), where the zones are outside a trajectory of edge of the ring when the zones are placed relative to the bush in the direction.