Coriolis Meter Electronics for Liquid Fraction in Gas
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Solution Overview
Problem
Existing Coriolis mass flow meters struggle to accurately and quickly determine the liquid flow fraction in gas flows, especially during two-phase flows, due to fluctuations in frequency and phase measurements, leading to errors in mass and volume flow rate calculations.
Innovation Solution
The implementation of meter electronics that receive sensor signals from a Coriolis flow meter, process them to generate a 90-degree phase shift, compute frequency responses, and determine instantaneous flow stream density, allowing for precise calculation of liquid flow fraction by comparing it to predetermined gas and liquid densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional notch filter methods are used to determine pickoff signal frequency, then the system works well under quiescent conditions with uniform flow material, but the frequency and phase measurements become inaccurate during two-phase flows where frequency fluctuates rapidly
Solution Approach 1:
The patent applies dynamics by making the filter bandwidth adaptive rather than fixed. The notch filter dynamically adjusts its bandwidth based on the detected frequency fluctuations, allowing it to track rapid frequency changes during two-phase flows while maintaining accuracy under quiescent conditions. This dynamic adaptation resolves the contradiction between reliability under stable conditions and adaptability during transient two-phase flow states.
Solution Approach 2:
The patent changes the parameter of filter bandwidth from a static value to a dynamically variable parameter. By monitoring frequency fluctuations and adjusting the bandwidth accordingly, the system maintains accurate frequency and phase measurements across varying flow conditions, including rapid frequency transitions during two-phase flows where traditional fixed-bandwidth filters fail.
2Measurement precision
If the notch filter bandwidth is kept narrow to improve frequency resolution, then frequency measurements are more precise under stable conditions, but the filter cannot track rapidly changing frequencies during two-phase flows
Solution Approach 1:
The patent makes the filter bandwidth dynamic, allowing it to be narrow under stable conditions for high precision measurements and wide during rapid frequency transitions for fast tracking. This dynamic adjustment of the bandwidth parameter resolves the contradiction between measurement precision and tracking speed by adapting the filter characteristics to the current flow state.
Solution Approach 2:
The system uses feedback by continuously monitoring the pickoff signal frequency and using this information to adjust the notch filter bandwidth in real-time. This feedback mechanism enables the filter to maintain optimal performance across varying conditions, achieving both high precision under stable conditions and fast tracking during frequency transitions.
3Ease of operation
If Demodulation is performed at a fixed frequency, then the process is simple and stable under quiescent conditions, but it fails when the actual frequency deviates due to rapid frequency transitions
Solution Approach 1:
The patent transitions from fixed-frequency demodulation to dynamic frequency-tracking demodulation. The system continuously determines the actual pickoff signal frequency and adjusts the demodulation frequency accordingly, maintaining measurement accuracy during rapid frequency transitions while preserving the simplicity of the demodulation process through automated frequency adaptation.
Solution Approach 2:
The system performs self-service by automatically tracking its own frequency and adjusting its demodulation process without external intervention. The notch filter and demodulation system self-adjust to the actual frequency conditions, maintaining accuracy during frequency transitions while keeping the operation simple through automated frequency determination and adaptation.
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 faster and more accurate determination of liquid flow fraction, reducing errors and providing real-time measurements, even during fluctuating conditions, thereby improving the accuracy of mass and volume flow rate calculations.
Implementation Method 1
a driver applies a force to the flow tube. The force causes the flow tube to oscillate
Implementation Method 2
As a material begins to flow through the flow tube, Coriolis accelerations cause each point along the flow tube to have a different phase with respect to other points along the flow tube
Data Source
AI summary
Meter electronics (20) for determining a liquid flow fraction in a gas flow material flowing through a flow meter (5) is provided according to an embodiment of the invention. The meter electronics (20) includes an interface (201) for receiving a first sensor signal and a second sensor signal from the flow meter (5) and a processing system (203) in communication with the interface (201). The processing system (203) is configured to receive the first and second sensor signals from the interface (201), determine a substantially instantaneous flow stream density of the gas flow material using the first sensor signal and the second sensor signal, compare the substantially instantaneous flow stream density to at least one of a predetermined gas density that is representative of a gas flow fraction of the gas flow material and a predetermined liquid density that is representative of a liquid flow fraction, and determine the liquid flow fraction from the comparison.