Charging Device for Densifying Frustoconical Preforms
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Solution Overview
Problem
Current chemical vapor infiltration methods are inefficient for densifying large, frustoconical-shaped porous preforms due to low loading capacity and high manufacturing costs, leading to increased production time and economic penalties.
Innovation Solution
A loading device with a stack of lower and upper crowns, each with injection and evacuation orifices, allows for optimal nesting of preforms and independent gas supply to minimize densification gradients, enabling higher loading capacity and homogenous densification within a reaction chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If preforms are loaded densely in the reaction chamber, then productivity increases, but gas circulation is insufficient leading to poor densification quality
Solution Approach 1:
The reaction chamber is segmented into multiple independent gas circulation zones using partition walls. Each zone can independently supply reactive gas to preforms through dedicated injection orifices, allowing dense loading while maintaining uniform gas distribution and densification quality across all preforms
Solution Approach 2:
Partition walls act as intermediaries that separate gas flow paths while still allowing thermal radiation and heat transfer between zones. These walls with integrated orifices enable independent gas circulation control for each preform position, resolving the conflict between high loading density and uniform gas supply
2Manufacturing precision
If large spaces are left between preforms for gas circulation, then densification quality improves, but loading capacity decreases
Solution Approach 1:
The reaction chamber is divided into multiple independent circulation zones using partition walls with injection orifices. This segmentation allows gas to be delivered directly to each preform position without requiring large inter-preform spaces, thereby increasing loading capacity while maintaining uniform gas distribution and densification quality
Solution Approach 2:
Gas circulation is transitioned from relying on lateral spaces between preforms to a vertical/direct delivery system through partition walls with orifices. This dimensional change in gas flow path enables dense preform arrangement while ensuring adequate gas supply to each position
3Productivity
If multiple preforms are loaded simultaneously, then productivity increases, but gas distribution becomes uneven causing densification gradients
Solution Approach 1:
Multiple preforms are processed simultaneously in separate circulation zones defined by partition walls. Each zone has independent gas injection through orifices in the partition walls, ensuring uniform gas distribution to all preforms while maintaining high processing throughput
Solution Approach 2:
Each circulation zone is equipped with locally optimized gas injection through orifices positioned in partition walls adjacent to each preform. This local quality approach ensures that each preform receives appropriate gas supply regardless of overall chamber loading, eliminating densification gradients while maintaining high productivity
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 significantly increases the loading volume and homogeneity of densification, reduces production downtime, and enhances the productivity of the densification process by ensuring uniform gas flow and circulation around each preform, minimizing pressure drops and densification gradients.
Implementation Method 1
The preheating of the reactant gas is usually carried out by passing the gas through a preheating zone located in the reaction chamber
Implementation Method 2
The densification of porous preforms by chemical vapor infiltration consists in placing the substrates in a reaction chamber of an infiltration installation by means of support equipment and in admitting into the chamber a reactive gas
Implementation Method 3
a first stack of a plurality of lower crowns arranged on the support plate, each lower crown comprising a plurality of injection orifices... a second stack of a plurality of upper crowns, each upper crown comprising a plurality of evacuation orifices
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
Charging device (100) for densifying porous preforms (160-163) of stackable shape in a reaction chamber of an infiltration furnace by controlled flow chemical vapour infiltration, the device comprising: - a support plate (110), - a first stack of a plurality of lower rings (140-144) placed on the support plate (110) and comprising a plurality of injection orifices extending between the outer periphery and the inner periphery of each ring, - a second stack of a plurality of upper rings (150-154) comprising a plurality of discharge orifices extending between the outer periphery and the inner periphery of each ring, - a first non-porous wall (130) of a shape and size identical to those of the porous preforms (160-163) that are to be densified and arranged on the support plate (110) inside the lower rings (140-144) of the first stack, said first non-porous wall extending between the support plate and the upper ring situated at the base of the second stack, - a second non-porous wall (170) of a shape and size identical to those of the porous preforms (160-163) that are to be densified, said second non-porous wall extending between the lower ring (143) situated at the top of the first stack and the upper ring (154) situated at the top of the second stack.