Dual Flame Rod Detection for Variable-Output Burner Abnormal Combustion
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Solution Overview
Problem
Conventional safety devices for gas burners cannot distinguish between the extension of flames due to increased output and abnormal combustion, making it difficult to detect abnormal combustion when the burner has variable output.
Innovation Solution
A combustion apparatus with a first flame rod and a second flame rod, where the positions and configurations allow the controller to differentiate between normal and abnormal combustion states by detecting contact with the flames, and includes a heat exchanger with specific sidewall arrangements to optimize flame rod placement and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single detection element is used to detect flame extension, then the device structure is simple, but it cannot distinguish between flame extension due to output increase and abnormal combustion
Solution Approach 1:
The detection function is segmented into two separate flame rods: the first flame rod detects flame extension at a first height, while the second flame rod detects flame extension at a second height. This segmentation allows the system to distinguish between normal flame extension (affecting only the first rod) and abnormal combustion (affecting both rods), resolving the contradiction between simple structure and accurate detection.
2Adaptability or versatility
If the burner output is variable, then the burner is more versatile, but it becomes impossible to distinguish between flame extension due to output changes and abnormal combustion
Solution Approach 1:
The system dynamically adapts to different burner output levels by using two flame rods positioned at different heights. The controller dynamically determines the combustion state based on which flame rod(s) are activated, allowing reliable abnormal combustion detection regardless of whether the burner is operating at high or low output, thus maintaining safety reliability across variable operating conditions.
3Measurement precision
If the second flame rod is positioned to detect abnormal combustion, then abnormal combustion can be detected, but the flame rod may be exposed to high temperatures during normal high-output operation
Solution Approach 1:
The second flame rod is positioned at a second height above the burner that is specifically optimized for detecting abnormal combustion while minimizing exposure to normal high-temperature flames. This localized positioning ensures the flame rod can detect abnormal combustion conditions (where flames extend to the second height) without being continuously exposed to high temperatures during normal operation, thus maintaining both detection capability and operational safety.
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
Enables accurate detection of abnormal combustion even with variable burner output, distinguishing between flame extensions caused by output increases and actual abnormal combustion, thereby improving safety and control.
Implementation Method 1
The first flame rod is arranged at a position where it makes contact with the flames produced at the burner in a normal combustion state... The second flame rod is arranged at a position where it makes contact with the flames produced at the burner in the normal combustion state when the burner is being controlled to be in the first output state, and does not make contact with the flames produced at the burner in the normal combustion state when the burner is being controlled to be in the second output state.
Data Source
AI summary
A combustion apparatus includes a burner configured to produce flames, a first flame rod and a second flame rod, and a controller. The burner is configured to be controlled, by the controller, to be in a first output state, and a second output state in which output is smaller than in the first output state. The first flame rod makes contact with the flames produced at the burner in a normal combustion state. The second flame rod makes contact with the flames produced at the burner in the normal combustion state when the burner is being controlled to be in the first output state, and does not make contact with the flames produced at the burner in the normal combustion state when the burner is being controlled to be in the second output state.