Multi-Flame Rod Combustion Control for Misfire Detection
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Solution Overview
Problem
Conventional combustion apparatuses face inaccuracies in monitoring combustion due to misfire detection issues, particularly when a flame rod breaks or strong winds cause false flame detection, leading to raw gas emission.
Innovation Solution
A combustion apparatus employing at least two flame detecting means, including current detection, to determine misfires and control fuel supply, with a determination unit assessing results from multiple detectors and executing re-ignition processes as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single flame rod is used for combustion monitoring, then the device complexity is low, but the reliability of combustion detection deteriorates when the flame rod breaks or fails
Solution Approach 1:
The flame detection function is segmented into multiple independent flame rods (first flame rod and second flame rod) that operate in parallel. Each flame rod independently monitors combustion, and the system compares their outputs to detect failures. This segmentation ensures that if one flame rod fails, the other can still provide detection capability, thereby improving reliability without requiring a completely redundant complex system.
Solution Approach 2:
The system implements feedback by continuously comparing the detection results from multiple flame rods. When a discrepancy is detected (one flame rod indicates flame present while another indicates absent), the control unit receives feedback about the potential failure and adjusts operation accordingly - either shutting down the burner or switching to alternative detection methods, thus maintaining reliable combustion monitoring.
2Measurement precision
If multiple flame detecting means are used to improve detection accuracy, then the reliability of combustion monitoring is enhanced, but the device complexity increases
Solution Approach 1:
The detection system is divided into multiple independent detection channels (first flame rod channel and second flame rod channel), each processing signals separately. This segmentation allows the system to compare results from different detection paths, improving measurement precision by identifying inconsistencies that indicate either actual combustion changes or detector failures.
Solution Approach 2:
The system changes the detection parameter by using different types of flame rods or positioning them at different locations around the burner. This diversification of detection parameters (spatial distribution, detection methodology) enhances measurement precision by providing multiple perspectives on combustion status, while the parameter differences themselves help identify when a specific detector may be failing.
3Object-affected harmful factors
If the system shuts down immediately when flame detection fails, then safety is improved by preventing raw gas emission, but productivity decreases due to unnecessary shutdowns from false detections
Solution Approach 1:
The system performs preliminary verification by cross-checking multiple flame rod detections before concluding that combustion has actually failed. When one flame rod indicates failure, the system first checks whether other flame rods also indicate failure or detect actual combustion conditions. This preliminary action distinguishes between genuine combustion failure and false detector signals, preventing unnecessary shutdowns while maintaining safety.
Solution Approach 2:
The control unit receives continuous feedback from multiple flame rods and uses this feedback to make informed decisions. When feedback from multiple detectors agrees on combustion status, the system acts confidently; when feedback diverges, the system investigates further before taking action. This feedback mechanism reduces false shutdowns while maintaining rapid response to actual combustion failures, balancing safety with productivity.
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
Enhances monitoring accuracy and safety by preventing raw gas emission through precise misfire detection and fuel control, even if one detector fails during operation.
Implementation Method 1
at least one of the flame detecting means may include a current detecting means detecting a value of current which passes through a flame
Data Source
AI summary
A combustion apparatus (water heater) includes a combustion unit (burner) combusting fuel, at least two flame detector (flame rods) detecting whether there is a flame or not in the combustion unit, a determination unit (control device) determining whether or not there is a misfire, based on detected results of the flame detectors, and a control unit (control device) stopping supply of the fuel to the combustion unit in response to a determined result of the determination unit.