Multi-Circuit Heat Exchanger Assembly With Staged Diffusion Welding
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Solution Overview
Problem
Current methods for producing heat exchangers by diffusion welding face challenges in achieving compactness with complex geometry channels, maintaining mechanical strength, controlling interface quality, and managing manufacturing costs, especially for exchangers with small dimensions and complex shapes.
Innovation Solution
A method involving the production of heat exchanger modules with at least two fluid circuits, where each circuit is formed by stacking and diffusion-welding grooved metal plates, allowing independent welding of each circuit to optimize welding force and temperature, enabling complex channel geometries and reduced deformation, and incorporating a hot isostatic compression (CIC) process for high-quality joint formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If diffusion welding is used to assemble heat exchanger plates, then mechanical strength of joints is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The method applies preliminary action by performing low-pressure CIC welding first to assemble plates while channels are still open, then later applying high-pressure CIC welding after channels are sealed. This staged approach simplifies the manufacturing process by breaking down the complex diffusion welding operation into manageable steps, each optimized for specific requirements.
Solution Approach 2:
The welding process is segmented into two distinct phases: first low-pressure CIC welding to join plates with open channels, then high-pressure CIC welding after channel sealing. This segmentation allows each welding stage to be optimized independently, reducing overall manufacturing complexity while maintaining joint strength.
2Manufacturing precision
If high pressure is applied during diffusion welding, then joint quality is improved, but channel deformation increases
Solution Approach 1:
The method performs the low-pressure welding action first while channels remain open and structurally supported, then seals channels and applies high pressure in a second stage. This preliminary action at low pressure prevents channel deformation that would occur if high pressure were applied from the beginning.
Solution Approach 2:
The welding process uses periodic action by applying pressure in two distinct stages: first low pressure to establish joints, then high pressure after channel sealing. This periodic application of varying pressure levels achieves high-quality interfaces without deforming the channel geometry.
3Force
If channels are sealed before diffusion welding, then welding force can be increased, but non-destructive testing becomes difficult
Solution Approach 1:
The method performs preliminary welding at low pressure while channels are open and accessible, allowing non-destructive testing to be conducted easily. After verification, channels are sealed and high-pressure welding is applied to achieve final joint quality, optimizing both inspectability and welding force.
4Volume of stationary object
If heat exchanger size is reduced for compactness, then volume is decreased, but manufacturing precision requirements increase
Solution Approach 1:
The method replaces traditional mechanical diffusion welding with CIC (Cold Isostatic Compression) welding, which uses fluid pressure transmission instead of direct mechanical contact. This substitution enables precise control of welding parameters even in compact heat exchangers, maintaining high interface quality control despite reduced size and volume.
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 results in compact heat exchangers with improved mechanical strength, reduced deformation, and enhanced interface quality, while allowing non-destructive testing and cost-effective production, suitable for complex geometries and small dimensions.
Implementation Method 1
assembly by diffusion welding of the stacked metal plates of each element
Implementation Method 2
incorporating a hot isostatic compression (CIC) process for high-quality joint formation
Implementation Method 3
Diffusion welding consists of obtaining a solid-state assembly by applying a hot force to the parts to be joined for a given time
Implementation Method 4
The force applied has a double function: it allows the docking, that is to say the bringing into contact of the surfaces to be welded, and it facilitates the elimination by creep-diffusion of the residual porosity in the joints
Data Source
Figure 1~1B
Figure 2~2A
Figure 3~3A
AI summary
The invention concerns a method for producing heat exchangers having at least two fluid circuits each comprising channels, comprising the following steps: a/ producing one or a plurality of elements of a first fluid circuit, each element of the first circuit comprising at least two metal plates, at least one of which comprises first grooves; b/ stacking the at least two metal plates of each element in such a way that the first grooves form the channels of the first circuit; c/ assembling each element of the first circuit by diffusion welding between the two stacked metal plates; d/ producing one or a plurality of elements of at least one second fluid circuit, each element of the second circuit comprising at least a portion of the channels of the second circuit; e/ assembling, either by diffusion welding, or by brazing, or by diffusion brazing between the element or elements of the first circuit and the element or elements of the second circuit.