Acoustic Flow Meter Liquid Detection via Chordal Pathways
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Solution Overview
Problem
Ultrasonic flow meters face challenges in accurately measuring natural gas flow due to liquid accumulations, which reduce the cross-sectional area and result in measurement errors, and existing liquid detection methods increase costs and complexity.
Innovation Solution
The system determines liquid accumulation by analyzing parameters of acoustic energy sent through transducer pairs without intersecting the liquid, using multiple chordal pathways and calculating parameters such as flow velocity profile fluctuations and cross-flow to detect liquid presence indirectly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated transducer pair is added to detect liquid by intersecting acoustic signals with the liquid surface, then liquid detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the existing transducer pairs serve dual functions: both measuring gas flow velocity and detecting liquid accumulation. By analyzing changes in acoustic signal parameters (transit time, amplitude) from the existing transducers, the system detects liquid without adding dedicated detection transducers, thus avoiding increased device complexity while maintaining detection capability
Solution Approach 2:
The existing acoustic measurement system serves itself by using the same transducer pairs that measure gas flow to also detect liquid presence. The system leverages the natural variations in acoustic signal characteristics caused by liquid accumulation to enable self-detection without requiring separate detection hardware
2Measurement precision
If acoustic signals traverse the flow meter horizontally to measure gas flow, then gas flow measurement is achieved, but liquid accumulation detection becomes difficult without additional transducers
Solution Approach 1:
The system continuously monitors acoustic signal parameters (transit time, amplitude) from the existing transducer pairs and uses feedback analysis to detect liquid accumulation. By comparing acoustic signal characteristics against expected values for gas-only flow, the system identifies liquid presence through parameter deviations, enabling detection without changing the horizontal measurement approach
3Productivity
If liquid accumulation is not detected, then flow measurement continues uninterrupted, but measurement errors increase due to reduced cross-sectional area
Solution Approach 1:
The system provides continuous feedback by monitoring acoustic signal parameters to detect liquid accumulation, enabling real-time identification of measurement error conditions. When liquid is detected through parameter changes, the system can alert operators or adjust measurements, maintaining continuous operation while preserving measurement accuracy through timely detection
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 allows for accurate detection of liquid accumulations without dedicated transducer pairs, reducing costs and complexity, and enables precise measurement of natural gas flow by accounting for changes in flow velocity profiles and cross-flow patterns.
Implementation Method 1
acoustic signals are sent back and forth across the gas stream to be measured. Based on parameters of received acoustic signals, the gas flow velocity at several distinct elevations in the flow meter is determined
Implementation Method 2
when liquid is present, the acoustic signal intersects and reflects from the surface of the liquid, rather than the lower-most portion of the meter, and thus the path length for the acoustic signal changes
Data Source
Figure 1A~1B
Figure 1C~5E
Figure 2
AI summary
Detecting liquid in an acoustic flow meter. At least some of the illustrative embodiments are methods comprising flowing a gaseous substance through a central passage of a meter body, sending acoustic signals along respective chordal pathways across the central passage (none of the chordal pathways intersect a lower portion of the central passage where liquid, if present during flow of the gaseous substance, accumulates), calculating a flow velocity of the gaseous substance proximate to each chordal pathway based on transit times of the acoustic signals along the respective chordal pathways, and determining the presence of a liquid accumulated in the lower portion based on the flow velocity proximate to each chordal pathway.