Microchannel Heat Exchanger Brazing for Precise Channel Formation

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Solution Overview

Problem

Existing methods for manufacturing micro channels in heat exchangers, such as machining or chemical etching, are costly and hazardous, and do not efficiently produce micro channels without material removal.

Innovation Solution

A method involving the application of brazing material with a specific composition and melting range to form micro channels between plates by heating and allowing them to cool, without completely melting the brazing material, to create a bonded heat exchanger resistant to corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If machining or chemical etching is used to manufacture micro channels, then micro channels can be produced, but the manufacturing cost increases and hazardous chemicals are required

Engineering Contradiction:
Improvemicro channel formationVSAvoidmanufacturing cost and safety
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention changes the manufacturing approach from material removal (machining, etching) to material addition and phase transformation. By controlling the brazing material's melting temperature parameter and applying partial melting followed by controlled cooling, micro channels are formed without hazardous chemicals or high-cost machining processes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces mechanical machining and chemical etching processes with a thermal-brazing process. Instead of using mechanical tools or hazardous chemicals, the method uses controlled heating to partially melt brazing material, which then forms micro channels through phase change and subsequent cooling, eliminating the need for dangerous substances

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If brazing material is completely melted, then good bonding is achieved, but micro channel structure is lost

Engineering Contradiction:
Improvebonding strengthVSAvoidmicro channel structure
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The invention applies partial melting instead of complete melting of the brazing material. By heating to a temperature that melts only a portion of the brazing material (below the complete melting point), the method achieves sufficient bonding while preserving the micro channel structure defined by the pattern on the plates

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The invention utilizes controlled phase transition of the brazing material from solid to partially liquid and back to solid. By heating below the complete melting point, partial phase change occurs creating a semi-liquid state that provides bonding while maintaining structural definition, then cooling solidifies the material while preserving micro channel geometry

Inventive Principle:
Principle #36Phase transitions

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 method allows for the cost-effective production of micro channels without hazardous chemicals, achieving efficient heat transfer and improved heat exchange capabilities while maintaining structural integrity.

Implementation Method 1

Heating the plates and the applied brazing material to a temperature exceeding an initial melting point of the applied brazing material while being lower than a temperature at which the brazing material is completely melted

Methodology Applied
Scientific EffectPartial melting: Melting

Implementation Method 2

Applying brazing material having a melting range in a pattern corresponding to the desired flow channel pattern on either or both of plates to be provided with micro channels

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP3247521B1A heat exchanger comprising micro channels and manufacturing thereof
Publication Date: 2021.08.18 SWEP INT AB
  • EP3247521B1 patent drawingFigure 1
  • EP3247521B1 patent drawingFigure 2
  • EP3247521B1 patent drawing

AI summary

A method for forming flow channels (MC) between two neighboring plates (P), comprises the steps of: Applying brazing material (B) having a melting point range in a pattern corresponding to the desired flow channel pattern on either or both of the plates (P), the height of the pattern exceeding the height of the desired flow channel; Arranging the plates on a distance from one another corresponding to the desired height of the flow channel (MC); Heating the plates and the applied brazing material to a temperature exceeding an initial melting point of the applied brazing material while being lower than a temperature at which the brazing material is completely melted; and Allowing the plates and the brazing material to cool down.