High Temperature Flame Sensor Using Photodiode and Remote Electronics
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Solution Overview
Problem
Conventional flame sensors in high-temperature combustion chambers require water cooling, which can lead to damage due to potential water leakage causing turbine housing contraction, and they are not effectively designed to operate at temperatures above 200°C without cooling.
Innovation Solution
A flame sensor apparatus with a photodiode located within the turbine to sense flame characteristics, using an electric cable assembly to convey the photocurrent to an electrically remote location at a lower temperature, eliminating the need for water cooling and allowing operation at temperatures above 200°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water cooling is used to cool temperature sensitive flame sensing electronics, then the electronics can operate at high temperatures, but water leakage may cause turbine housing contraction and damage
Solution Approach 1:
The patent extracts the temperature-sensitive electronics from the high-temperature combustion chamber environment by using an extended sensor structure. The sensing element reaches into the combustion chamber through an extension tube while the electronics remain outside the combustion chamber, eliminating the need for water cooling and avoiding water leakage damage.
Solution Approach 2:
The extension tube acts as an intermediary structure that allows the sensing element to access the high-temperature combustion chamber environment while maintaining a physical barrier that protects the electronics from direct exposure to extreme temperatures and potential water leakage issues.
2Measurement precision
If flame sensor components are located within the combustion chamber to detect flame, then flame detection is effective, but the components are exposed to high temperatures that exceed their operating limits
Solution Approach 1:
The flame sensor is segmented into distinct functional zones: the sensing element operates within the combustion chamber to detect flame, the extension tube provides thermal isolation, and the electronics are positioned outside the high-temperature zone. This segmentation allows each component to operate within its optimal temperature range.
Solution Approach 2:
The sensor assembly extends in the spatial dimension through the extension tube, allowing the sensing element to reach into the combustion chamber while the electronics remain in a cooler external environment. This dimensional extension resolves the temperature conflict between effective flame detection and component temperature tolerance.
3Productivity
If the flame sensor operates at high temperatures above 200°C, then the sensor can function in the combustion chamber environment, but conventional electronics cannot withstand such temperatures
Solution Approach 1:
The electronics are extracted from the high-temperature combustion chamber environment and positioned outside the combustion chamber. Only the essential sensing element remains inside to detect flame, while the temperature-sensitive electronics operate in a cooler external environment, ensuring their reliability.
Solution Approach 2:
The sensing element acts as a remote proxy or copy that experiences the high-temperature combustion chamber environment and transmits information about flame presence to the electronics, which remain protected in a cooler environment. This allows the system to maintain productivity in high temperature while preserving electronics reliability.
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 reliable flame detection without water cooling, reducing the risk of turbine damage and maintaining sensor functionality in high-temperature environments.
Implementation Method 1
The sensor assembly includes a photodiode, at the first location, for sensing characteristics of a flame within a combustion chamber of the turbine. The photodiode outputs an electrical photocurrent that has an electrical current value that is indicative of the characteristics of the flame.
Data Source
AI summary
A flame sensor apparatus includes a sensor assembly. The sensor assembly includes a photodiode for sensing characteristics of a flame. The photodiode outputs an electrical photocurrent. The sensor assembly includes an electrical assembly that is electrically remote from the sensor assembly. The sensor assembly includes an electric cable assembly extending from the sensor assembly to the electrical assembly. The electric cable assembly includes an electrical cable to electrically convey the photocurrent to the electrical assembly. At least the sensor assembly is configured and constructed to experience and continue to operate at a temperature at or greater than 200° C.