Labyrinth Seal Wear Protection via Laser Cladding
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Solution Overview
Problem
Labyrinth seals in gas turbines face wear issues due to thermal expansion and friction, leading to reduced sealing effectiveness and the need for costly and time-consuming repair methods, which do not adequately protect against future wear.
Innovation Solution
Sealing rings with a wear protection ring segment made of a metal matrix embedded with wear protection particles, built up layer-by-layer using a laser beam on truncated sealing rings, providing enhanced wear resistance and controlled distribution of particles for optimal protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealing rings are made from standard materials and machined with conventional tolerances, then manufacturing is simpler and less costly, but wear resistance is insufficient and sealing effectiveness deteriorates over time
Solution Approach 1:
The sealing ring is constructed as a composite structure consisting of a base sealing ring made from standard materials and a wear protection ring segment built up on its friction contact surface. The wear protection ring segment contains a metal matrix with embedded wear protection particles (such as ceramic particles), combining the advantages of standard materials with enhanced wear resistance properties.
Solution Approach 2:
The wear protection ring segment is applied selectively only to the friction contact surface of the sealing ring where wear occurs, rather than treating the entire sealing ring. This localized approach provides enhanced wear resistance precisely where needed while keeping the rest of the sealing ring simple and cost-effective to manufacture.
2Reliability
If wear protection layers are applied through galvanic or electrolytic methods, then wear protection is provided, but the process is time-consuming and cost-intensive
Solution Approach 1:
The patent replaces time-consuming galvanic or electrolytic coating processes with a laser-based build-up welding process. The wear protection ring segment is built up layer-by-layer directly on the sealing ring using laser melting of powder material, which is significantly faster and more cost-effective while providing superior wear protection with embedded particles.
Solution Approach 2:
The manufacturing process transitions from chemical/electrochemical methods (galvanic/electrolytic coating) to thermal processing (laser build-up welding). This parameter change enables faster processing speeds, reduced manufacturing time, and the ability to embed wear protection particles within the matrix structure rather than just coating the surface.
3Reliability
If plasma spraying is used to apply wear protection material, then wear protection is achieved, but access limitations prevent uniform coating and sufficient wear protection
Solution Approach 1:
The patent replaces plasma spraying with laser build-up welding, which offers superior access to complex geometries and friction contact surfaces. The laser beam can precisely melt and fuse powder material directly onto the sealing ring surface even in hard-to-reach areas, ensuring uniform application of the wear protection ring segment with embedded particles throughout the entire friction contact region.
4Ease of repair
If sealing rings are rebuilt by cutting off and laser build-up welding without wear protection particles, then repair is achieved, but future wear is not protected against
Solution Approach 1:
The repair process is enhanced by incorporating wear protection particles (such as ceramic particles) into the metal matrix of the wear protection ring segment during the laser build-up welding process. This creates a composite structure that not only restores the sealing ring geometry but also provides superior wear resistance for future operation, preventing the recurrence of wear problems.
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 solution ensures superior wear protection and maintains a high sealing effect over time, while being more cost-efficient and applicable for repair, with improved resistance to wear in contact regions.
Implementation Method 1
a mixture of a metal powder and wear protection particles is supplied to the truncated seals and fused thereon layer-by-layer by a laser beam
Data Source
AI summary
In sealing rings for a labyrinth seal that are arranged on a rotationally symmetrical component and in frictional contact with a stationary run-in layer, a part of the sealing ring (8) that contacts the run-in layer is in the form of a wear protection ring segment (15) that is built up on a truncated sealing ring (14) and which includes a metal matrix (16) with wear protection particles (13) embedded therein. The manufacture of the wear protection ring segment is carried out by laser build-up welding, wherein the proportion of wear protection particles contained in the metal powder flow supplied to the laser beam can be controlled and increased in an edge or tip region of the sealing ring.