Flame Rod Analysis System for Contamination Detection
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Solution Overview
Problem
Existing flame monitoring systems using flame rectification cannot distinguish between a high-resistance flame and a contaminated flame rod, leading to unnecessary burner shut-downs due to corrosion and contamination.
Innovation Solution
A system comprising energy storage, a pulsed source, a buffer, and a processor that analyzes the flame rod by providing voltage or current pulses and determining buffered voltages to differentiate between a flame short, no flame, and a contaminated flame rod, using a reference resistor to measure resistance and produce flags for each condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flame rectification is used to sense flame presence, then the system can detect whether a flame is present, but it cannot distinguish between a high-resistance flame and a contaminated flame rod, leading to false flame-out detections
Solution Approach 1:
The patent segments the flame detection process into multiple measurement phases: a first measurement taken during a voltage pulse to detect flame shorts, and a second measurement taken after the pulse to detect flame presence. This temporal segmentation allows the system to distinguish between different failure modes (contaminated rod vs. actual flame out) that would otherwise appear identical in continuous measurement systems.
Solution Approach 2:
The system employs periodic voltage pulses applied to the flame rod rather than continuous monitoring. By periodically interrupting the measurement with voltage pulses and comparing readings before and after pulses, the system can identify contamination conditions versus true flame-out conditions, resolving the ambiguity inherent in continuous flame rectification monitoring.
2Productivity
If flame rods are exposed to flames continuously, then they can monitor flame presence, but they accumulate corrosion and contamination over time that increases resistance and triggers false flame-out events
Solution Approach 1:
The system performs preliminary diagnostic measurements by applying voltage pulses and comparing pre-pulse and post-pulse readings. This preliminary action allows the system to detect contamination conditions before they cause false flame-out shutdowns, enabling early warning and maintenance scheduling while maintaining continuous monitoring operations.
Solution Approach 2:
The system uses feedback from comparative measurements (pre-pulse versus post-pulse voltage readings) to determine flame rod condition. When the difference between measurements exceeds a threshold, the system generates a contamination warning without triggering a false flame-out shutdown, allowing operators to service the rod on schedule rather than causing unnecessary burner interruptions.
3Device complexity
If the system uses a single DC voltage threshold for flame detection, then the circuit is simple, but it cannot differentiate between no flame, flame short, and high-resistance flame conditions
Solution Approach 1:
The patent transforms the static single-threshold detection system into a dynamic multi-phase measurement system. By taking measurements at different times (before and after voltage pulses) and comparing the changes, the system achieves sophisticated flame condition differentiation using relatively simple circuitry that only needs to capture and compare voltage levels at different moments.
Solution Approach 2:
The system uses periodic voltage pulses to create distinct measurement opportunities. The first measurement during the pulse detects flame shorts, while the second measurement after the pulse detects flame presence and contamination conditions. This periodic measurement approach enables multiple diagnostic capabilities without requiring complex continuous monitoring circuitry.
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 system effectively distinguishes between a high-resistance flame, a contaminated flame rod, and a true flame-out, preventing unnecessary shut-downs by accurately monitoring the flame rod's condition and resistance, thereby improving burner reliability.
Implementation Method 1
Many burners rely on flame rectification to sense the presence of a flame. In flame rectification an AC signal is sent to two electrodes contacted by the flame. Because the current from one half of the AC cycle is preferentially conducted through the flame, the AC signal is rectified to produce a noisy DC voltage.
Implementation Method 2
The capacitor has a first terminal and a second terminal, wherein the first terminal is connectable to a flame rod and the second terminal connectable to ground
Implementation Method 3
The operational amplifier has a positive terminal, a negative terminal, and an output. The positive terminal is connected to the first terminal, the negative terminal is connected to the output
Data Source
AI summary
A flame rod analysis system, methods for determining a condition of a flame and a flame rod, and circuits for determining a condition of a flame and a flame rod. The flame rod analysis system comprises energy storage connectable to a flame rod, a pulsed source connected to the energy storage and providing a voltage pulse or a current pulse, and a buffer to allow a processor to measure a buffered voltage at various time points. Flame rod analysis systems can distinguish between various flame conditions (no flame, low flame, etc.) while simultaneously characterizing the condition of the flame rod (shorted to ground, contaminated, etc.). Some flame rod analysis systems can directly measure the resistance of the flame rod.