Metal Loss Measurement Using Reference Element Noise Filtering
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Solution Overview
Problem
Existing methods for measuring metal loss in process equipment, such as erosion and corrosion, often produce false alarms due to temperature variations and noise, leading to unreliable metal loss detection and potential damage to equipment.
Innovation Solution
A method that calculates a confidence measure of resistivity changes using a reference element and a measurement element, filtering out noise by comparing stability and temperature changes, and applying this confidence measure to provide a trustworthy value for real metal loss, thereby suppressing false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical resistance measurement is used to detect metal loss, then erosion and corrosion can be monitored, but temperature variations cause false alarms and reduce measurement reliability
Solution Approach 1:
The patent introduces a reference element as an intermediary that is not exposed to process flow but experiences the same temperature variations. This reference element serves as a mediator to compensate for temperature effects on the measurement element's resistance, allowing differentiation between temperature-induced resistance changes and those caused by actual metal loss.
Solution Approach 2:
The patent changes the measurement parameter from absolute resistance values to a ratio between reference element resistance and measurement element resistance. This parameter transformation eliminates the temperature dependency while preserving the sensitivity to metal loss, as temperature variations affect both elements equally and cancel out in the ratio calculation.
2Measurement precision
If reference element is used for temperature compensation, then temperature effects are reduced, but the reference element cannot follow accurate temperature variations and produces false metal loss or gain readings
Solution Approach 1:
The patent implements a feedback mechanism where the resistance ratio between reference and measurement elements is continuously monitored. When the ratio indicates metal loss or gain beyond expected thresholds, the system triggers alarms or adjusts measurements, providing feedback to distinguish true metal loss from false readings caused by temperature lag.
Solution Approach 2:
The patent makes the measurement system dynamic by continuously monitoring resistance changes over time and comparing them against expected behavior patterns. The system adapts to changing conditions by using the time-varying ratio of resistances, allowing it to distinguish between transient temperature effects and genuine metal loss trends.
3Loss of information
If sand probes and corrosion probes are deployed, then erosion and corrosion detection is enabled, but false alarms increase and hide real alarm signals
Solution Approach 1:
The patent applies preliminary action by establishing baseline resistance ratios and expected variation patterns before deployment. The system pre-configures alarm thresholds based on normal operating conditions, allowing it to distinguish between routine temperature-induced variations and genuine metal loss events that warrant alarm signals.
Solution Approach 2:
The patent transforms the alarm detection parameter from absolute resistance changes to ratio-based metal loss calculations. This parameter change reduces false alarms by eliminating temperature-dependent resistance variations, allowing the system to focus alarm triggers on genuine metal loss events while maintaining sensitivity to real threats.
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
This method effectively reduces false alarms by up to 99% while retaining 100% of true alarms, ensuring accurate detection of metal loss and preventing equipment damage.
Implementation Method 1
measuring electrical resistance Re across said one or more measurement element, measuring electrical resistance Rr across the reference element
Data Source
AI summary
Method of measuring metal loss from equipment in process systems. Probes installed for monitoring one or both of erosion and corrosion (metal loss) in process equipment use results from resistivity measurements in a measurement element and a reference element to produce a measurement of metal loss in the measurement element exposed to process flow and may trigger an alarm when measured metal loss exceeds a threshold level. Prior art methods produce numerous false alarms hiding true alarms. The present method ignores these false alarms that are common in known methods by calculating confidence measures that are included in the metal loss calculations to attenuate noise that otherwise would produce false alarms or misinterpretation of the corrosion or erosion state in the process equipment being monitored.