Gas Blower Burner Flame Ionization Feedback Control
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Solution Overview
Problem
Air ratio-controlled forced-air gas burners are highly susceptible to disturbances in flow resistances within the air, fuel gas-air mixture, heating gas, and exhaust gas paths, limiting their operational stability and efficiency across a wide output modulation range.
Innovation Solution
The method involves temporarily enriching the fuel gas-air mixture during selected operating states and analyzing the resulting flame ionization signal swing to adjust the lower permissible fan speed, thereby compensating for changes in flow resistances and maintaining a stable air ratio across the modulation range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If air ratio control is used to optimize combustion efficiency, then pollutant emissions are reduced and firing efficiency is improved, but the burner operation becomes highly susceptible to disturbances in flow resistance
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the flame ionization signal and comparing it with a target value. When deviations are detected due to flow resistance changes, the system automatically adjusts the air-to-fuel ratio to restore optimal combustion, thereby maintaining both low emissions and operational stability.
Solution Approach 2:
The system dynamically changes the air-to-fuel ratio parameter in response to detected flow resistance disturbances. By adjusting this critical parameter based on real-time ionization signal feedback, the burner maintains stable combustion and efficient operation despite varying flow conditions in the exhaust path.
2Productivity
If the lower modulation limit is set to enable low-load operation, then the burner can operate at lower fan speeds, but flow resistance disturbances cause unstable flame behavior and potential safety hazards
Solution Approach 1:
The feedback control system continuously monitors the flame ionization signal and makes real-time adjustments to the air-to-fuel ratio. This ensures that even at low modulation limits and reduced fan speeds, the flame remains stable and safe by compensating for flow resistance disturbances that would otherwise cause instability.
Solution Approach 2:
The system performs preliminary detection of flow resistance changes through the ionization signal and proactively adjusts the air-to-fuel ratio before unstable flame behavior occurs. This preventive approach allows the burner to maintain safe operation at lower modulation limits by anticipating and compensating for potential instability.
3Use of energy by stationary object
If the fan speed is reduced to operate at lower load, then energy consumption is reduced, but the ionization signal intensity decreases making air ratio control unreliable
Solution Approach 1:
The system compensates for the reduced ionization signal intensity at lower fan speeds by dynamically adjusting the air-to-fuel ratio parameter. This ensures that the ionization signal remains sufficiently strong and reliable for accurate air ratio control, even when operating at lower energy consumption levels.
Solution Approach 2:
The feedback control mechanism continuously adapts to the changing ionization signal characteristics at different fan speeds. By adjusting control parameters based on real-time signal feedback, the system maintains reliable air ratio control across the entire modulation range, including low-speed operation where signal intensity is reduced.
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 stabilizes the burner operation by preventing flame lift-off or flashback, ensuring stable combustion and reduced pollutant emissions, while expanding the accessible power modulation range and maintaining efficient heat delivery.
Implementation Method 1
An ionization electrode detects an actual flame ionization signal I in the combustion zone, which arises as a result of a voltage applied to a burner flame
Data Source
Figure 1~2
Figure 3~4
AI summary
The method according to the invention for stabilizing an operating behavior of a power-modulating, air ratio-controlled gas blower burner, compensates for disturbances accompanying changed flow resistance in a combustion air path, burnable gas-air mixed path, heating gas path and/or waste gas path by adjusting the power modulation range. In selected operating states of the gas blower burner and in deviation from normal control operation, the burnable gas-air mixture is temporarily and briefly enriched with burnable gas and the actual flame ionization signal is observed. When a flame ionization stroke observed during enriching is smaller than a first tolerance amount, a lower permissible blower rotational speed is increased. Thereafter, the burner control returns to the normal control operation.