Diffusion-Bonded Heat Exchanger Compression Using a Vacuum Capsule
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing diffusion bonding methods for manufacturing channelled devices face challenges in maintaining high vacuum and ensuring uniform compression, leading to nonuniformity and structural issues, particularly in larger products, due to the complexity of sealing and isostatic pressure.
Innovation Solution
A method involving a semi-finished product enclosed in a capsule, pressurized with inert gas, and subjected to mechanical pressing by mobile equipment, allowing for controlled, directional compression and reduced vacuum requirements, thereby simplifying the oven design and reducing the risk of structural collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high vacuum is maintained in the oven, then degassing of materials is improved, but the plant size must be large and sealing complexity increases
Solution Approach 1:
The system divides the vacuum environment into two separate zones: the oven chamber and the capsule interior. The capsule acts as an independent vacuum-sealed container that can be evacuated separately from the oven, allowing the oven to operate at atmospheric pressure while the capsule maintains high vacuum for degassing. This segmentation eliminates the need for complex oven sealing while achieving reliable degassing.
Solution Approach 2:
The capsule serves as an intermediary device between the atmospheric-pressure oven environment and the high-vacuum degassing requirement. By placing the semi-finished product inside the capsule and evacuating the capsule separately, the system achieves effective degassing without requiring the entire oven to be vacuum-sealed, thus reducing sealing complexity while maintaining degassing quality.
2Manufacturing precision
If isostatic pressure is applied through pressurized gas, then uniform compression is improved, but the oven must withstand high pressures and temperatures increasing complexity
Solution Approach 1:
The compression function is segmented from the oven system and transferred to the capsule. The capsule is designed to collapse under external atmospheric pressure applied by a press, creating isostatic compression of the product inside. This eliminates the need for the oven to withstand high pressures and temperatures simultaneously, reducing oven complexity while maintaining compression uniformity.
Solution Approach 2:
The capsule acts as an intermediary that transfers the compression force from the external press to the semi-finished product. By using the capsule as the pressure-containing element rather than the oven, the system achieves uniform isostatic compression without requiring the oven to be designed for high-pressure and high-temperature withstand capability, thus reducing overall system complexity.
3Manufacturing precision
If capsule collapse is used for compression, then isostatic pressure is achieved, but the capsule may yield allowing gas penetration and losing pressing effectiveness
Solution Approach 1:
The capsule is designed with differentiated structural properties: the walls are made sufficiently thin and flexible to allow controlled collapse and isostatic pressure application, yet sufficiently strong to maintain integrity during the pressing process. This local optimization of wall thickness and material properties ensures the capsule yields just enough to provide uniform pressure without complete failure that would allow gas penetration and loss of pressing effectiveness.
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
Enables efficient and economical manufacturing of larger channelled devices with improved uniformity and reduced risk of structural defects, by using inert gas pressurization and controlled mechanical pressing, facilitating degassing and reducing the need for complex vacuum sealing.
Implementation Method 1
The capsule is inserted into an oven, arranged between a support plate and at least one piston, and is subjected to vacuum.
Implementation Method 2
The semi-finished product is pressed together with the capsule, according to a packing direction, by means of at least one piston and simultaneous heating of the oven.
Implementation Method 3
The semi-finished product is pressed together with the capsule, according to a packing direction, by means of at least one piston and simultaneous heating of the oven.
Data Source
Figure 1
Figure 2
AI summary
Method for manufacturing a heat exchanger according to the diffusion bonding technique, comprising the following steps in succession (Step 1) preparation of a plurality of etched plates (SL) and (Step 2) packing of the etched plates so as to define a semi-finished product (MF) of the heat exchanger, (Step 3) insertion of the semi-finished product inside a metal capsule (C), (Step 4) insertion of the capsule inside a oven (H), weakly pressurized with inert gas, (Step 5) application of a pressing according to a packing direction (X) by means of at least one piston (P1, P2, P3...Pn) and simultaneous heating of the oven, (Step 6) removal of the capsule.