Impulse Line Blockage Detection via Pressure Fluctuation Correlation
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Solution Overview
Problem
Existing methods for detecting blockages in impulse lines coupled to differential pressure transmitters are inefficient, particularly in distinguishing between blockages in higher and lower pressure impulse lines and are influenced by fluid flow rates, making it difficult to set accurate thresholds for detection.
Innovation Solution
An apparatus and method that include units for detecting and calculating fluctuations and square sums of static and differential pressures, correlation coefficients, and a blockage rate calculation to determine the presence of blockages in impulse lines, allowing for independent detection from fluid flow rates and convenient threshold setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fluctuation variance methods are used to detect blockages, then blockage detection can be performed, but the detection is influenced by fluid flow rates making it difficult to set accurate thresholds
Solution Approach 1:
The patent segments the differential pressure fluctuation into two distinct components: higher pressure impulse line fluctuation and lower pressure impulse line fluctuation. By calculating fluctuation variances separately for each impulse line and comparing their ratio to a threshold, the method can identify which specific line is blocked without being influenced by overall fluid flow rate changes. This segmentation resolves the contradiction by making blockage detection independent from fluid flow rate while maintaining high accuracy.
2Reliability
If differential pressure fluctuations are used for blockage detection, then blockage can be detected, but it is difficult to distinguish between blockages in higher and lower pressure impulse lines
Solution Approach 1:
The patent divides the differential pressure fluctuation into two separate fluctuation components corresponding to the higher pressure impulse line and the lower pressure impulse line. By calculating the fluctuation variance for each component separately and comparing their ratio, the method not only detects whether a blockage exists but also identifies which specific impulse line is blocked. This segmentation approach simultaneously achieves reliable blockage detection and preserves blockage location information.
Solution Approach 2:
The patent uses feedback by comparing the ratio of higher pressure fluctuation variance to lower pressure fluctuation variance against a predetermined threshold. This feedback mechanism provides clear diagnostic information: when the ratio exceeds the threshold, it indicates a blockage in the lower pressure impulse line; when the ratio is below the threshold, it indicates a blockage in the higher pressure impulse line. This feedback approach enhances both detection reliability and location identification.
Data Source
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AI summary
A detecting apparatus includes the following units. A pressure detecting unit detects in time series higher and lower static pressures and a differential pressure. Fluctuation calculating units calculate time series data sets of a differential pressure fluctuation, a higher static pressure fluctuation, and a lower static pressure fluctuation. Square sum calculating units calculate the square sum of the time series data sets of the differential pressure fluctuation, the square sum of the time series data sets of the higher static pressure fluctuation, and the square sum of the time series data sets of the lower static pressure fluctuation. A correlation coefficient calculating unit calculates first and second correlation coefficients. An intermediate variable calculating unit calculates an intermediate variable. A blockage rate calculating unit calculates a blockage rate. A determination unit determines a blockage of higher and lower pressure impulse lines with reference to the blockage rate.