Double-Layer Heat-Exchange Wall With Iron Interphase Bonding
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Solution Overview
Problem
Existing double-layer heat-exchange walls in heat exchangers suffer from reduced thermal conductivity due to mechanical clearances between layers, which also fail to effectively respond to simultaneous piercing of both layers, compromising integrity and safety, especially in chemically reactive environments.
Innovation Solution
A method involving interposing a pure iron leaf between two metal sheets, followed by mechanical pressing, welding, and hot isostatic pressing to create a dense ductile interphase that fills the gap, ensuring uniform mechanical junction and enhanced thermal conductivity, while preventing fluid leakage and crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical clearance or gap is left between the two layers of the double-layer heat-exchange wall, then the safety and detection capability are improved, but the thermal conductivity is deteriorated
Solution Approach 1:
The patent introduces an intermediary substance (metal powder or brazing material) to fill the gap between the inner and outer layers. This intermediary serves dual purposes: it maintains the safety function by allowing gap connection to detection systems while simultaneously improving thermal conductivity by replacing the insulating gas/air in the gap with a thermally conductive material.
Solution Approach 2:
The patent changes the physical and thermal parameters of the gap by filling it with metal powder or brazing material. This transforms the gap from a low thermal conductivity space to a high thermal conductivity region, while the gap itself remains present for safety detection purposes.
2Temperature
If the gap between layers is filled to improve thermal conductivity, then the thermal conductivity is improved, but the ability to detect fluid leakage is reduced
Solution Approach 1:
The patent uses an intermediary substance (metal powder or brazing material) that fills the gap thermally while allowing the gap space to remain connected to detection systems. The intermediary improves thermal contact without sealing off the detection pathway for fluid leakage monitoring.
3Manufacturing precision
If cold machining is performed to reduce thickness and improve thermal contact, then the manufacturing precision is improved, but the mechanical strength is reduced
Solution Approach 1:
The patent replaces mechanical cold machining with a thermal process (brazing or metal powder filling). Instead of mechanically removing material to improve contact, the invention uses thermal energy to create metallurgical bonds or fill gaps, achieving superior thermal contact without compromising mechanical strength through material removal.
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 method achieves thermal conductivity exceeding 80% of an equivalent solid wall, significantly extending service life by deflecting fatigue cracks and maintaining integrity, with improved resistance to fluid pressure and thermal stress.
Implementation Method 1
The method achieves thermal conductivity exceeding 80% of an equivalent solid wall
Implementation Method 2
hot isostatic pressing conducted at a temperature of between 800°C and 1200°C, at a pressure of between 108 Pa and 2.108 Pa
Data Source
AI summary
A method for manufacturing a double-layer heat-exchange wall including first and second metal layers includes the following successive steps: (i) providing a first metal sheet forming the first layer, a second metal sheet forming the second layer, and a leaf of iron Fe0 having a thickness of between 10 μm and 100 μm; (ii) assembling the first and second metal sheets and the leaf of iron Fe0, the leaf interposed between the first and second metal sheets; (iii) mechanical pressing of the assembly at a minimum pressure of 1 MPa; (iv) peripheral welding of the pressed assembly; and (v) heat treatment of the welded assembly, the heat treatment being implemented by hot isostatic pressing conducted at a temperature of between 800° C. and 1200° C., at a pressure of between 108 Pa and 2.108 Pa, for a period of between 1 hour and 3 hours.