Annular Substrate CVI Loading Modules for Uniform Densification
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Solution Overview
Problem
Existing methods for densifying porous annular substrates by chemical vapor infiltration are inefficient due to complex and lengthy loading processes, sealing issues, and suboptimal use of furnace volume, which hinder uniformity and efficiency, especially when dealing with large numbers of substrates.
Innovation Solution
The method involves using unit modules with a support tray and injection tube to stack porous annular substrates in a densification furnace, allowing for simpler and automated formation of stacks, improved compactness, and reduced need for intermediate support trays, enabling better sealing and preheating, and facilitating semi-forced flow CVI methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional loading with intermediate support trays and vertical pins is used, then substrates can be supported in the furnace enclosure, but the loading becomes long and complex to make, and sealing between support trays and stack sections is difficult to guarantee
Solution Approach 1:
The loading structure is divided into independent unit modules, each comprising a support tray with integrated injection tube. This segmentation eliminates the need for complex intermediate support trays and vertical pins, while improving sealing reliability through self-contained modules that can be independently assembled and sealed.
Solution Approach 2:
The support tray and injection tube are merged into a single integrated unit module. This combination simplifies the overall loading structure by eliminating separate intermediate support components, reduces assembly complexity, and improves sealing reliability through fewer interface points between components.
2Productivity
If traditional thick support trays are used, then substrates can be supported, but the volume occupied in the furnace enclosure is not optimized, and the loading rate is reduced
Solution Approach 1:
The support tray thickness parameter is optimized by transitioning to thinner, more efficient unit module designs. This parameter change increases the number of unit modules that can be stacked within the furnace enclosure volume, thereby improving loading rate and volume utilization without compromising substrate support functionality.
Solution Approach 2:
The loading structure transitions from a two-dimensional tray-based support system to a three-dimensional stacked unit module configuration. This dimensional change maximizes vertical space utilization in the furnace enclosure, increasing loading capacity and productivity while maintaining adequate support functionality.
3Adaptability or versatility
If traditional loading structures are used, then substrates can be densified, but sealing problems make it difficult to implement semi-forced flow CVI methods, and densification uniformity is compromised
Solution Approach 1:
The unit module is designed as a self-contained unit with integrated gas distribution capabilities through the injection tube. This self-service design eliminates dependence on complex external sealing arrangements between multiple components, enabling reliable implementation of semi-forced flow CVI methods and ensuring uniform densification across all substrates in the stack.
Solution Approach 2:
The problematic intermediate support trays and their associated sealing interfaces are extracted from the system. By removing these complex sealing requirements, the invention enables more versatile CVI method implementation while improving densification uniformity through simpler, more reliable unit module stacking with fewer potential leak paths.
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 approach simplifies the densification process, enhances sealing, increases loading efficiency, and achieves more uniform substrate densification by eliminating the need for complex intermediate support structures and improving gas circulation, allowing for more effective implementation of CVI technologies.
Implementation Method 1
a gas phase comprising a matrix material precursor is introduced inside the stacks of substrates so as to form the matrix in the porosity of the substrates
Implementation Method 2
The injection tube of each unit module also plays the role of thermal mass ensuring a gas preheating function
Data Source
AI summary
A method for densifying porous annular substrates by chemical vapor infiltration, includes providing a plurality of unit modules including a support tray on which substrates are stacked, the support tray including a gas intake opening extended by an injection tube disposed in an internal volume formed by the central passages of the stacked substrates, the injection tube including gas injection orifices opening into the internal volume, forming stacks of unit modules in the enclosure of a densification furnace and injecting, into the stacks of unit modules, a gas phase including a gas precursor of a matrix material to be deposited within the porosity of the substrates.