Nuclear Magnetic Flow Meter Adaptive Impedance Matching
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Solution Overview
Problem
Nuclear magnetic flowmeters face challenges in accurately measuring slug flow in media with varying liquid and gas distributions due to complex impedance matching requirements, leading to inefficient power transfer and poor signal-to-noise ratios, especially in media with high salt content.
Innovation Solution
The method involves determining and setting specific 'tuning' and 'matching' parameters for surge and film areas based on reflected power, allowing for precise differentiation and optimized measurement settings, reducing the need for complex data analysis algorithms and improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional impedance matching is used for surge flow measurement, then the RF circuit can operate with standard settings, but power transfer efficiency deteriorates and signal-to-noise ratio becomes poor
Solution Approach 1:
The patent applies dynamics by making the matching network adjustable and adaptive to different flow conditions. The matching network can be dynamically reconfigured to match the RF coil impedance for different liquid volume ratios, ensuring optimal power transfer whether measuring surge flow or film flow conditions.
Solution Approach 2:
The patent changes the electrical parameters of the matching network to optimize power transfer. By adjusting the matching network parameters (such as capacitor values or inductor values) based on the detected flow regime, the system achieves optimal impedance matching and maximizes power transfer efficiency to the RF coil.
2Measurement precision
If sophisticated data analysis algorithms are used to differentiate surge and film areas, then measurement capability is improved, but device complexity and data processing time increase
Solution Approach 1:
The patent replaces complex software-based data analysis algorithms with a hardware-based electrical measurement approach. Instead of using sophisticated algorithms to analyze flow patterns, the system uses electrical measurements (impedance, power consumption) of the RF circuit to directly detect and differentiate between surge and film flow regimes, significantly simplifying the system.
Solution Approach 2:
The system uses the RF circuit's own electrical characteristics (impedance, power consumption) as the measurement signal to detect flow regime changes. The RF circuit essentially measures itself, providing direct feedback about the flow conditions without requiring external complex sensing or analysis systems.
3Measurement precision
If tuning and matching are adjusted before each measurement, then measurement accuracy is improved, but measurement time and operational complexity increase
Solution Approach 1:
The patent performs preliminary detection of the flow regime using electrical measurements of the RF circuit before the actual flow rate measurement. By detecting whether surge flow or film flow conditions exist beforehand, the system can pre-configure the matching network parameters to match the detected flow regime, avoiding time-consuming adjustments during the measurement process.
Solution Approach 2:
The system continuously monitors the electrical characteristics (power consumption, impedance) of the RF circuit and uses this feedback to automatically detect flow regime changes. When a change in flow regime is detected, the system automatically adjusts the matching network parameters to maintain optimal power transfer, eliminating the need for manual retuning.
4Power
If the medium is considered as additional load in RF resonant circuit, then power transfer optimization is enabled, but matching settings become dependent on medium characteristics
Solution Approach 1:
The patent makes the matching network dynamic and adaptable to different medium conditions. Rather than being fixed for a specific medium type, the matching network can be reconfigured based on the actual flow regime and medium characteristics, allowing optimal power transfer across different operating conditions while maintaining versatility.
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 approach enables accurate and efficient measurement of flow rates and phase proportions in slug flow by optimizing power transfer and signal detection, reducing errors and data processing complexity.
Implementation Method 1
an RF circuit with external electronics and with at least one RF coil designed to generate excitation signals stimulating the medium and/or to detect measurement signals emitted by the medium
Implementation Method 2
The medium flowing through the RF coil must be considered an additional load in this RF resonant circuit
Data Source
AI summary
Described is a method for operating a nuclear magnetic flow meter for determining the flow rate of a medium with low or no salinity flowing through a measuring tube with surge flow, with a measuring device, wherein the measuring device comprises an RF circuit with external electronics and with at least one RF coil designed to generate excitation signals stimulating the medium and/or to detect measurement signals emitted by the medium, wherein a surge region of the surge flow is characterized by a surge of liquid medium and the liquid medium fills the entire measuring tube cross-section, and a film region of the surge flow consists of a large gas bubble occupying a dominant part of the measuring tube cross-section and a liquid film filling the remaining measuring tube cross-section.According to the invention, the disadvantages of known methods are minimized and data handling is simplified by setting the "tuning" and "matching" parameters for a surge range or for a film range, wherein "tuning" allows the frequency of the RF circuit to be adjusted to achieve resonance, and "matching" allows the impedance of the RF coil to be adapted to that of the external electronics, by performing a nuclear magnetic measurement, by determining, based on signal amplitudes, whether a surge range or a film range is located in the RF coil, and by determining, using the signal amplitudes, the water-liquid ratio and/or the gas-volume fraction in the surge range and in the film range.