Self-Calibrating Turbine Blade Clearance Sensor System
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Solution Overview
Problem
Current clearance sensing systems face challenges in maintaining measurement accuracy over time due to temperature effects and long-term drifts, requiring frequent lab calibration and lacking self-correction mechanisms for channel mismatch errors.
Innovation Solution
A self-calibration system for multiple channel clearance sensors that uses capacitive, microwave, or eddy current sensors to dynamically adjust and correct channel responses through ratiometric techniques, phase detection, and automatic gain control, enabling continuous monitoring and correction of sensor signals without human intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequent lab calibration is performed to maintain measurement accuracy, then measurement precision is improved, but loss of time and productivity deteriorate due to system shutdown and human intervention requirements
Solution Approach 1:
The patent implements self-calibration capability where the sensor system automatically detects and corrects its own channel mismatches using test signals and processing circuitry, eliminating the need for manual lab calibration and human intervention while maintaining measurement accuracy over time
Solution Approach 2:
The system performs preliminary calibration actions by incorporating test signals and self-diagnostic circuitry that continuously monitor and correct channel mismatches before they affect measurement accuracy, enabling proactive maintenance without system shutdown
2Stability of the object's composition
If temperature compensated components and low drift components are used to reduce variation, then stability is improved, but device complexity increases and no provision is made for detecting and correcting drifts over time
Solution Approach 1:
The patent implements feedback mechanisms where the processing circuitry continuously monitors the output signals from multiple sensing channels, detects mismatches caused by temperature effects or drift, and automatically adjusts gain or offset to maintain channel matching, providing active correction rather than passive component selection
Solution Approach 2:
The patent replaces reliance on mechanically selected temperature compensated or low drift components with an electronic/digital solution using processing circuitry that automatically detects and corrects channel mismatches through signal processing algorithms
3Measurement precision
If manual calibration is performed to correct channel mismatch errors, then measurement precision is improved, but ease of operation deteriorates due to required human intervention and system disassembly
Solution Approach 1:
The patent implements self-calibration capability where the sensor system automatically detects and corrects its own channel mismatches using test signals and processing circuitry, eliminating the need for manual lab calibration and human intervention while maintaining measurement accuracy over time
Data Source
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AI summary
Self-calibration of a multiple channel clearance sensor system (110), which in one embodiment includes at least one sensor (40) for measuring at least one clearance parameter signal between a stationary object and a rotating object of a rotating machine. The sensor output is processed as a clearance parameter by an offset correction section (137) configured to determine an offset error in the clearance parameter signal, which is used by a level shifter (120). The level shifter is also switchably coupled to the clearance parameter signal wherein the output of the level shifter, which may be amplified and digitally converted, is processed by a signal level analyzer (154) to determine a channel gain signal.