Flat-Tube Heat Exchanger Bonding Without Fin Coating Melt
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Solution Overview
Problem
Heat exchangers face challenges in bonding fins to flat tubes without melting hydrophilic and antifouling coatings, which are essential for preventing dew scattering and contamination, especially in indoor units where high temperatures during brazing processes can cause coating materials to melt.
Innovation Solution
The bonding of fins to flat tubes is achieved using an epoxy-based adhesive applied between the anticorrosive layer and the fin, with a heat treatment at a lower temperature (approximately 200°C) to prevent the coating material from melting, ensuring the hydrophilic and antifouling properties are maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fin tube heat exchanger is disassembled into a fin tube and a tube sheet for replacement, then the tube can be replaced, but the fin is damaged and cannot be reused
Solution Approach 1:
The heat exchanger is divided into modular units: a tube assembly (with tube and tube sheet) and a fin assembly, which can be independently replaced. This allows the tube to be replaced without damaging the fin, resolving the contradiction between ease of replacement and fin reusability
Solution Approach 2:
The tube is nested within the tube sheet, and the tube assembly is nested within the fin assembly. This hierarchical nesting allows the inner tube to be replaced independently while preserving the outer fin structure, enabling easy tube replacement without fin damage
2Reliability
If the entire heat exchanger is replaced when the tube deteriorates, then a new heat exchanger is available, but resource waste occurs
Solution Approach 1:
The deteriorated tube is extracted from the heat exchanger assembly and replaced with a new tube, while the functional fin and tube sheet are retained. This extraction approach restores heat exchanger performance without wasting the still-functional components, resolving the contradiction between reliability and resource waste
3Strength
If the tube is welded to the tube sheet, then a strong connection is achieved, but the tube cannot be replaced without damaging the tube sheet
Solution Approach 1:
The connection between tube and tube sheet transitions from a permanent static weld to a dynamic, replaceable insertion fit. The tube can be inserted and removed from the tube sheet multiple times while maintaining adequate connection strength, resolving the contradiction between connection strength and ease of replacement
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 effectively prevents the scattering of water droplets and contamination by maintaining the hydrophilic and antifouling properties of the fin surface, enhancing the bonding strength and reducing production costs while ensuring efficient heat exchange operations.
Implementation Method 1
a heat exchanger comprising a refrigerant passage forming unit configured to form a refrigerant passage in which a refrigerant flows
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
There are provided a heat exchanger having a flat tube and a fin bonded together, without causing melting of a coating material covering the fin, and a method of manufacturing thereof. A heat exchanger (1) includes: a flat tube (3) having a flat cross-sectional shape and covered with an anticorrosive layer (11); and a fin (21) bonded to the flat tube with a bonding agent (41) on a first surface of the anticorrosive layer interposed therebetween, and covered with a coating material (27), the first surface of the anticorrosive layer having been roughened, and the bonding agent being fixed to the roughened first surface.