Brazed Spherical Closure Element for Irregular Internal Passages
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Solution Overview
Problem
Standard-sized metallic balls often fail to seat properly in internal passages of components due to dimensional or shape irregularities, requiring non-standard balls that are costly and time-consuming to obtain, especially when aluminide coatings need removal or defects are present, leading to delays in manufacturing.
Innovation Solution
A closure element with a spherical body made of a superalloy and a plurality of extensions made of a different material, which are inserted into the passage and bonded using a braze material during a thermal cycle to form a metallurgical seal, even in irregularly shaped or oversized closure sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard-sized metallic balls are used to close internal passages, then manufacturing simplicity is maintained, but sealing reliability fails when closure site dimensions are out of tolerance
Solution Approach 1:
The closure element incorporates extensions with different materials and properties at specific locations on the spherical body. These extensions are made of materials with different coefficients of thermal expansion or brazeability to locally adapt to irregular closure site geometries and achieve reliable sealing where standard balls fail.
Solution Approach 2:
The closure element uses composite construction with a spherical body made of one material and extensions made of different materials. This composite structure allows the closure element to simultaneously provide structural integrity and adapt to varying closure site conditions through material selection optimized for each functional requirement.
2Reliability
If non-standard metallic balls are obtained to seal irregular closure sites, then sealing reliability is improved, but manufacturing time and cost increase significantly
Solution Approach 1:
The closure element design allows standard spherical bodies to be used with modified parameters through the addition of extensions. Rather than obtaining custom-sized balls, the solution changes the geometric parameters of the closure element by adding extensions that can be brazed to the spherical body, maintaining standard ball inventories while achieving custom-fit sealing capability.
Solution Approach 2:
The extensions are pre-formed and then brazed to the spherical body in a preliminary action before insertion into the closure site. This preliminary preparation allows the closure elements to be manufactured in advance using standard balls, and the extensions are added to adapt to specific closure site requirements, avoiding delays during final assembly.
3Ease of manufacture
If aluminide coating is removed manually to clean closure sites, then coating interference is eliminated, but dimensional accuracy deteriorates creating oversized closure sites
Solution Approach 1:
The extensions are designed to locally compensate for the dimensional changes caused by manual coating removal. By positioning extensions at specific locations on the spherical body, the design accommodates the oversized closure site dimensions created by aggressive coating removal methods, ensuring proper sealing despite the loss of dimensional accuracy.
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 effectively seals internal passages in components with irregular dimensions or defects, reducing manufacturing delays and costs by using a customizable closure element that forms a reliable bond with the passage walls, ensuring proper sealing and flow patterns.
Implementation Method 1
applying a braze material at the closure site; and subjecting the component to at least one thermal cycle such that the braze material forms a metallurgical bond with the spherical body, the plurality of extensions and the passage wall to seal the internal passage
Data Source
AI summary
A closure element for an internal passage in a component, and a related method and turbine blade or nozzle are disclosed. The closure element includes a spherical body made of a first superalloy, and a plurality of extensions extending from a surface of the spherical body. The plurality of extensions made of the same, similar or different material other than the first superalloy. Subjecting the component to at least one thermal cycle causes a braze material to form a metallurgical bond with the spherical body, the plurality of extensions and the passage wall to seal the internal passage.