Stainless Steel Heat Transfer Fin Layout for Corrosion and Overheating
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Solution Overview
Problem
Conventional heat exchangers in combustion devices face issues with thermal efficiency due to corrosion from acid drains and partial overheating of stainless steel-based heat transfer fins, leading to decreased conductivity and increased hot water outlet temperatures during restarts.
Innovation Solution
The heat transfer fins are designed with elliptical tube insertion holes and cut portions that guide combustion exhaust gas effectively, preventing overheating and corrosion, while the elliptical shape and staggered arrangement of heat-transfer tubes enhance heat recovery and reduce post-boiling phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If heat transfer fins are made of copper-based metal for high heat conductivity, then thermal efficiency is improved, but corrosion resistance to acid drain deteriorates
Solution Approach 1:
The patent uses stainless steel-based metal for heat transfer fins that combines adequate heat conductivity with superior corrosion resistance to acid drain, resolving the contradiction between thermal efficiency and corrosion resistance by selecting a material that balances both properties rather than using pure copper or pure stainless steel
2Reliability
If heat transfer fins are made of stainless steel-based metal for corrosion resistance, then reliability is improved, but heat conductivity deteriorates causing partial overheating
Solution Approach 1:
The patent applies local quality by creating cut portions at specific locations (upper ends and lower ends) of the heat transfer fins to reduce heat retention in those areas, while maintaining the stainless steel material properties in other regions for corrosion resistance and adequate heat conduction
3Loss of energy
If heat transfer fins have high heat conductivity, then thermal efficiency is improved, but residual heat after operation stop increases causing post-boiling phenomenon
Solution Approach 1:
The patent applies local quality by creating cut portions at specific locations (upper ends and lower ends) of the heat transfer fins to reduce heat retention in those areas, while maintaining the stainless steel material properties in other regions for corrosion resistance and adequate heat conduction
4Reliability
If drain adheres to lower ends of heat transfer fins, then corrosion resistance is challenged, but flow of combustion exhaust gas is obstructed
Solution Approach 1:
The patent applies local quality by creating cut portions at the lower ends of the heat transfer fins to prevent drain accumulation in those areas, thereby maintaining gas flow pathways while the stainless steel material provides corrosion resistance where drain contact occurs
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 design improves thermal efficiency by preventing deformation and corrosion, ensuring smooth gas flow and uniform heat recovery, and reduces the risk of high hot water outlet temperatures during restarts by minimizing heat retention in the fins.
Implementation Method 1
the heat transfer fins and the heat-transfer tubes are both made of copper-based metal having high heat conductivity for increasing thermal efficiency
Implementation Method 2
steam contained in the combustion exhaust gas condenses on the surfaces of the heat transfer fins into drain
Data Source
AI summary
A heat transfer fin (31) made of stainless steel-based metal for a heat exchanger, has a plurality of upper stage heat-transfer-tube insertion holes (611), a plurality of lower stage heat-transfer-tube insertion holes formed (612), upper end cut portions (651) formed between the adjacent upper stage heat-transfer-tube insertion holes (611), and lower end cut portions (652) formed between the adjacent lower stage heat-transfer-tube insertion holes (612), wherein the upper end cut portions (651) are formed so as to extend from a fin upper end portion (311) beyond lower ends of the upper stage heat-transfer-tube insertion holes (611) to positions in the vicinity of upper ends of the lower stage heat-transfer-tube insertion holes (612), and the lower end cut portions (652) are formed so as to extend from a fin lower end portion (312) to positions above the lower ends of the lower stage heat-transfer-tube insertion holes (612).