Surface Combustion Burner Deflectors for Flame Stability
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Solution Overview
Problem
Conventional surface combustion gas burners face limitations in flame-holding performance, power variation range, and pollutant emissions, with high costs associated with stainless steel fiber coatings, leading to restricted power settings and increased emissions of NOx and CO.
Innovation Solution
A surface combustion gas burner design featuring a metal or refractory combustor grid with integral deflectors and micro-tubes, allowing for efficient gas flow guidance and ejection, which maintains flame adherence at varying power levels while reducing temperature and emissions, and is cost-effective.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stainless steel sheet perforated with small holes and slits is used as a combustion surface, then flame-holding performance is improved, but the power variation range is limited to 1 to 3
Solution Approach 1:
The combustion surface is divided into multiple zones with different hole sizes and geometries. Small holes provide stable flame holding at low power, while larger holes enable operation at high power. This local differentiation of geometric properties allows the burner to adapt to a wide power range while maintaining reliable flame attachment across all settings.
2Power
If the burner operates at low power with a conventional design, then power setting is reduced, but the combustion surface temperature increases significantly causing flashbacks
Solution Approach 1:
Different regions of the combustion surface have optimized hole geometries that control local flame characteristics. At low power settings, the flame interacts primarily with zones designed for stable attachment, preventing excessive temperature rise and flashback while maintaining adequate power output.
Solution Approach 2:
The combustion surface acts as an intermediary between the gas mixture and the flame, with its specific hole geometry mediating the interaction to prevent direct flame contact with the sheet at low power, thereby reducing temperature and preventing flashback.
3Power
If the burner operates at high power with a conventional design, then power output is increased, but the flame separates from the surface causing increased pollutant emissions
Solution Approach 1:
The combustion surface incorporates larger holes in specific zones that maintain adequate gas velocity and turbulence even at high power settings. This ensures the flame remains attached to the combustion surface, preventing flame lift-off and the associated increase in NOx and CO emissions.
4Reliability
If a layer of stainless steel fibers is added to the perforated sheet, then flame-holding performance and thermal insulation are improved, but the cost of the burner increases significantly
Solution Approach 1:
The invention replaces the expensive stainless steel fiber layer with a simple perforated sheet design that achieves equivalent flame-holding performance through optimized hole geometry. This substitution dramatically reduces material costs while maintaining the necessary flame attachment characteristics.
Solution Approach 2:
The stainless steel fiber layer, which adds significant cost, is completely removed from the design. The essential flame-holding function is extracted and achieved instead through the geometric configuration of the holes in the perforated sheet itself, eliminating the need for the expensive fiber material.
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 burner achieves high flame-holding performance across a wide power range, reduces pollutant emissions, and extends operational longevity with improved combustion efficiency and reduced NOx and CO emissions, suitable for diverse applications including water heaters.
Implementation Method 1
each deflector includes a gas flow guiding part and a part connecting it to the sheet, said guiding part being spaced away from the sheet so as to form with it at least one lateral gas ejection opening
Implementation Method 2
combustion takes place on a combustion surface or combustion grid, through which the gas-air mixture is routed under pressure
Data Source
AI summary
The invention concerns a surface-combustion gas burner comprising a combustion grate consisting of a metal sheet pierced with a series of slots. This burner is remarkable in that said metal sheet comprises a series of deflectors made in one piece with said metal sheet and protruding on the outer face of same, each deflector extending longitudinally and laterally above the entire surface of a slot, and in that each deflector comprises a guide portion for guiding the gas flow and a junction portion joining to the metal sheet, said guide portion being spaced from the metal sheet in such a way as to provide therewith at least one lateral gas ejection port, said deflectors being disposed in pairs in such a way that the lateral gas ejection ports of same face each other.