Flame Sensor Window Contamination Detection
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Solution Overview
Problem
In combustion systems, such as gas turbines, it is challenging to determine if a flame is extinguished due to contamination on the flame sensor window, which can mimic a malfunction or a true flame-out condition, leading to potential damage from inappropriate fuel ignition.
Innovation Solution
A flame sensor system that includes a photodetector and a light source, where the light source emits electromagnetic radiation that passes through or reflects off the window, allowing the sensor to differentiate between contamination and a genuine flame-out condition by varying the radiation pattern, enabling the detection of contamination and maintaining accurate flame detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flame sensor with a window is used to detect flame presence, then flame detection capability is improved, but contamination on the window causes sensitivity loss that cannot be distinguished from actual flame-out conditions
Solution Approach 1:
The system performs preliminary contamination detection by measuring light transmission through the window before making flame presence determinations. A light source emits light through the window to a photodetector, and the system monitors transmission levels to detect contamination buildup, allowing proactive maintenance scheduling and distinction between contamination-induced sensitivity loss and actual flame-out conditions
Solution Approach 2:
The patent introduces an intermediary light source and photodetector system that measures light transmission through the window independently of flame detection. This intermediary measurement system provides information about window contamination status, which is then used to compensate or adjust the flame detection readings, resolving the ambiguity between contamination and actual flame conditions
2Reliability
If the flame sensor operates in a noisy combustion environment, then flame detection capability is maintained, but it becomes difficult to distinguish between contamination effects and actual flame-out conditions
Solution Approach 1:
The system segments the detection function into two independent parts: flame detection (using the flame-sensitive photodetector) and contamination detection (using the light source and photodetector in transmission mode). By separating these functions, the system preserves diagnostic information about window condition while maintaining flame detection capability, preventing information loss in the noisy combustion environment
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 contamination and a genuine flame-out condition, ensuring timely fuel shutdown and preventing damage by accurately indicating the presence or absence of a flame, even in the presence of contaminants like ash or dust.
Implementation Method 1
The photodetector is configured to generate an electrical signal proportional to an intensity of electromagnetic radiation
Implementation Method 2
at least some of the electromagnetic radiation emitted by the source reflects back toward the photodetector when contamination is present on the window
Data Source
AI summary
A flame sensor detects the presence of a flame in a combustion system in which the flame emits light. The flame sensor includes a body connectable with the combustion system. A photodetector is supported in the body. The photodetector responds to light emitted by the flame and generates an electrical signal proportional to an intensity of the light. A window is supported in the body and located between the combustion system and photodetector. The window is susceptible to contamination from the combustion system and the contamination may decrease sensitivity of the photodetector. A light source is supported in the body. The light source emits light so that a predetermined amount of the light emitted by the light source reflects into the photodetector when contamination is present on the window and the photodetector generates a signal indicative of contamination on the window.