Impulse Line Clogging Detection via Variance Ratio Normalization
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Solution Overview
Problem
Existing methods for detecting impulse line clogging in differential pressure transmitters are influenced by fluid flow rates, leading to increased operator workload and costs due to the need for adjusting threshold values and experimental standard fluctuation variance.
Innovation Solution
An impulse line-clogging detecting apparatus that includes a differential pressure detecting unit, fluctuation calculating unit, variance ratio calculating unit, and variance ratio correcting unit to determine clogging by calculating a correction value for flow rate changes, allowing precise detection without flow rate influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the standard fluctuation variance is obtained experimentally under fixed flow rate conditions, then the clogging detection can be performed, but the operator workload increases and apparatus costs increase when flow rate changes require adjustment of threshold values or setting values
Solution Approach 1:
The invention changes the parameter used for clogging detection from absolute fluctuation variance to a normalized variance ratio. By dividing the measured fluctuation variance by the standard fluctuation variance obtained under fixed flow rate conditions, the system creates a dimensionless ratio that automatically adapts to different flow rates, eliminating the need for operator intervention when flow conditions change
Solution Approach 2:
The standard fluctuation variance obtained under fixed flow rate conditions is made universally applicable across different operating conditions. Instead of requiring separate calibration for each flow rate, the normalized variance ratio allows the same standard value to serve as a reference for clogging detection across a wide range of flow rates, reducing both operator workload and apparatus complexity
2Measurement precision
If the threshold value or setting value is adjusted depending on the flow rate, then the clogging detection accuracy is maintained, but the apparatus costs increase when automation is required
Solution Approach 1:
The invention transforms the detection parameter from absolute variance (which requires flow-rate-dependent calibration) to a normalized variance ratio. This parameter transformation enables the system to maintain detection accuracy across different flow rates without requiring complex automated adjustment mechanisms, thereby reducing apparatus costs while preserving measurement precision
Solution Approach 2:
The normalized variance ratio enables the system to self-adjust to different flow conditions automatically. The ratio inherently compensates for flow rate variations without requiring external control systems or automated calibration mechanisms, allowing the apparatus to maintain accuracy through its own internal normalization process rather than requiring additional expensive automation equipment
Data Source
AI summary
An impulse line-clogging detecting apparatus. The apparatus is provide with: a differential pressure detecting unit that detects a differential pressure of a fluid, and outputs time-series data of the differential pressure. Fluctuations are determined by a differential pressure fluctuation calculating unit that calculates a differential pressure fluctuation, and a fluctuation variance calculating unit that calculates a variance of the differential pressure fluctuation. Based upon the calculated variance, a variance ratio calculating unit calculates a variance ratio of the differential pressure fluctuation variance to a differential pressure fluctuation variance obtained in advance in a normal state of the high and low pressure side impulse lines. A variance ratio correcting unit calculates a correction value for suppressing a change of the variance ratio. Finally; a clogging determining unit determines whether the high and low pressure side impulse lines are clogged, based on the variance ratio corrected by the variance ratio correcting unit.