Heat Exchanger Sealing Layer for Tube-Fin Contact Faults
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mechanical type heat exchangers experience contact faults between tubes and fins due to springback effects and material thinning, leading to air passages that reduce heat exchanger performance, with existing solutions being complex and expensive.
Innovation Solution
Applying a thin layer of sealing material with a melting temperature below 300°C on the tubes or fins, which is activated by heating to fill contact defects between the tubes and fins, eliminating air passages without altering the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If tubes are made thinner to reduce weight and save material, then weight is reduced, but contact faults and interstices between tubes and fins increase due to springback effects
Solution Approach 1:
A sealing material layer is introduced as an intermediary substance between the tube and fin. This sealing layer compensates for contact faults and interstices that occur during crimping, especially when tubes are thin-walled and prone to springback. The sealing material fills gaps and ensures reliable thermal contact without requiring thicker tubes or more complex crimping processes.
Solution Approach 2:
The sealing material undergoes a phase change from solid to liquid when heated above its melting point (below 300°C). This parameter change allows the sealing material to flow into interstices and contact faults, then solidify to create a reliable seal. The low melting point enables this transformation using simple heating methods without affecting the aluminum alloy tube and fin structure.
2Productivity
If sealing material layer is applied and heated to fill interstices, then heat exchanger performance is improved, but manufacturing process complexity increases
Solution Approach 1:
The sealing material is designed with a low melting point (below 300°C) that allows it to be activated by simple heating methods such as hot air or induction heating. This parameter choice enables the sealing process to be integrated into existing manufacturing lines without requiring complex high-temperature furnaces or specialized equipment, thus maintaining manufacturing simplicity while achieving improved sealing.
Solution Approach 2:
The sealing process replaces complex mechanical alignment and tight-tolerance crimping operations with a thermal process. Instead of relying solely on precise mechanical positioning and high-force crimping to eliminate all gaps, the sealing material is applied and then heated to melt and fill remaining interstices. This substitution of mechanical precision requirements with a thermal sealing process simplifies the overall manufacturing system.
3Reliability
If high heating temperature is used to melt sealing material, then sealing effectiveness is improved, but mechanical integrity of aluminum alloy tube and fin is compromised
Solution Approach 1:
The sealing material is specifically selected with a melting point below 300°C, which is significantly lower than the melting point of aluminum alloy (above 600°C). This parameter differentiation allows the sealing material to melt and flow for effective sealing while the aluminum alloy tube and fin remain solid and maintain their mechanical integrity. The large temperature gap between the sealing material transition and the structural material transition enables independent control of sealing and structural properties.
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 solution effectively seals contact faults, improving heat exchanger performance by up to 15% in high fluid flow scenarios without increasing manufacturing complexity or cost, and does not compromise the mechanical integrity of the heat exchanger.
Implementation Method 1
the sealing material is heated so as to cause it to melt and to seal any fault in contact between the tube and each collar
Implementation Method 2
during the radial expansion of the tubes, the latter, by deforming, tend to widen the necks delimiting the passage holes of the tubes in the fins
Implementation Method 3
the radial expansion of the tubes is followed by a slight elastic return of the tubes in the opposite direction to the expansion. This springback effect
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a heat exchanger comprising at least one tube (12) and at least one fin (14), the tube (12) being connected to the fin (14) by crimping said tube in a collar (16) made in the fin (14). The tube (12) or the fin (14) is coated with a layer of a material (22) different from those of the tube and the fin. Said layer forms a reserve of material (22) for sealing a potential gap between the tube (12) and the collar (16). Said sealing material (22) can be activated by melting.