Heat Exchanger Collar Design for Brazing Defect Reduction
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Solution Overview
Problem
Conventional heat exchanger manufacturing processes are complex and prone to defects, particularly due to the tube expanding process and the use of torch brazing, which increases the defect rate and poses health risks from excess flux.
Innovation Solution
The heat exchanger design features an aluminum coolant tube and fin coupled without a tube expanding process, using a collar with elastic deformation and furnace brazing to simplify manufacturing and reduce defects, with a connecting material infiltrating between the collar and tube for secure bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If torch brazing is used for connecting coolant tubes, then individual brazing connection can be achieved, but the defect rate increases and health risks from excess flux occur
Solution Approach 1:
The patent replaces torch brazing with induction heating technology. The induction heating device generates an electromagnetic field that induces eddy currents in the coolant tube, heating it rapidly and uniformly without direct flame contact. This eliminates the harmful effects of torch brazing (excess flux, high defect rate) while achieving reliable brazing connections through controlled electromagnetic heating.
2Strength
If tube expanding process is used to assemble fin with coolant tube, then tight contact can be achieved, but the manufacturing process becomes more complex and defect rate increases
Solution Approach 1:
The patent incorporates the fin collar design with predetermined geometric parameters (inner diameter, outer diameter, thickness) during the fin manufacturing stage. The collar is pre-formed with dimensions that enable direct insertion and brazing of the coolant tube without requiring subsequent tube expanding operations. This preliminary structuring eliminates the need for complex tube expanding equipment and processes while ensuring adequate contact tightness for reliable assembly.
3Ease of manufacture
If collar inner diameter is made larger than tube outer diameter for easy assembly, then assembly becomes simpler, but contact tightness and bonding strength are reduced
Solution Approach 1:
The patent optimizes the collar dimensional parameters within specific ranges: inner diameter 0.95-1.05 times the tube outer diameter, outer diameter 1.2-1.5 times the tube outer diameter, and thickness 0.5-1.5 times the tube wall thickness. These parameter changes enable the collar to provide both easy assembly (slight interference fit) and strong bonding (adequate contact area for brazing) simultaneously, resolving the contradiction between assembly ease and bonding strength.
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 simplifies the manufacturing process, reduces defect rates, and eliminates health hazards from flux, while maintaining effective heat transfer and corrosion resistance.
Implementation Method 1
the collar may include an inner diameter portion and an outer diameter portion, wherein the inner diameter portion may be elastically deformed upon insertion of the coolant tube along the inside thereof
Implementation Method 2
a connecting material may be infiltrated between the collar and the coolant tube
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
According to the present invention, a heat exchanger comprises a coolant tube(2), and a fin (4) having a collar (12) coupled with the coolant tube (2) and projected from a plate part (10), wherein the collar (12) includes a non-contacting part (16) having an inner diameter larger than an outer diameter of the coolant tube (2), the non-contacting part (16) not contacting an outer surface of the coolant tube (2), and a contacting part (14), an inner surface of the contacting part (14) contacting the outer surface of the coolant tube (2) when the coolant tube (2) is inserted, wherein a connecting member is positioned between an inner surface of the non-contacting part (16) and the outer surface of the coolant tube (2). Accordingly, without a tube expanding process for tube expanding the coolant tube, the coolant tube may be brought in tight contact with the fin. Further, a furnace brazing process is performed to minimize the defect rate.