Coriolis Flow Meter Multi-Phase Error Compensation
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Solution Overview
Problem
Existing inline measuring devices, particularly Coriolis mass flow meters, face significant measurement errors when dealing with two-phase or multi-phase media due to fluctuations in oscillation measurement signals, which are not accurately compensated by conventional methods like the 'bubble theory, leading to inaccuracies in mass flow and density measurements.
Innovation Solution
The method involves tracking and exciting specific eigenmodes of the measuring tube that are not excited by the exciter arrangement but are dominantly excited by the moving mixture, allowing for the detection of two- or multi-phase mixtures and the design of compensation algorithms based on eigenmode parameters to correct measurement errors, including those not explained by the classical bubble theory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods (bubble theory) are used to compensate for two-phase mixture errors, then the device complexity remains low, but measurement precision deteriorates due to inaccurate compensation of density and mass flow errors
Solution Approach 1:
The patent applies dynamics by making the measurement system adaptive to changing two-phase flow conditions. The evaluation algorithm dynamically adjusts compensation based on detected eigenmode parameters, allowing the system to adapt to varying mixture compositions and flow regimes rather than using fixed compensation values.
Solution Approach 2:
The patent changes physical parameters by utilizing eigenmode frequencies and damping ratios as diagnostic parameters for two-phase flow detection. By monitoring changes in these vibrational parameters, the system identifies the presence and characteristics of two-phase mixtures, enabling dynamic compensation adjustments.
2Measurement precision
If eigenmode tracking and excitation methods are implemented to detect two-phase mixtures, then measurement precision improves through accurate error compensation, but device complexity increases due to additional signal processing requirements
Solution Approach 1:
The patent utilizes mechanical vibration by exciting the measuring tube at its eigenfrequencies and analyzing the vibrational response. The system deliberately induces vibrations and monitors eigenmode parameters (frequency, damping, phase) to detect two-phase flow conditions and compensate for measurement errors in density and mass flow.
Solution Approach 2:
The patent implements feedback by using the detected eigenmode parameters to continuously adjust and refine the compensation algorithm. The system monitors vibrational characteristics, compares them against reference values, and dynamically modifies compensation factors to maintain accurate measurements under varying two-phase flow conditions.
3Measurement precision
If classical bubble theory compensation is used, then the ease of operation remains high with simple calculation rules, but measurement precision deteriorates due to inability to account for dynamic mixture characteristics
Solution Approach 1:
The patent replaces the mechanical/bubble theory-based compensation approach with a vibrational analysis approach. Instead of relying on bubble distribution models, the system substitutes mechanical vibration analysis and eigenmode parameter monitoring to detect and compensate for two-phase flow effects, providing more accurate dynamic characterization.
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 improves measurement accuracy by accounting for the dynamic characteristics of the mixture volume within the vibrating measuring tube, enabling precise correction of density and mass flow errors in two-phase mixtures, such as liquids with entrained gas, with reproducible correction values and simplified calculation rules, and reduces the complexity of signal processing requirements.
Implementation Method 1
The at least one measuring tube is caused to vibrate within at least a first one of a plurality of natural eigenmodes
Implementation Method 2
The oscillation measurement signals comprise at least a first oscillation measurement signal component corresponding to said first natural eigenmode
Implementation Method 3
the measurement of the mass flow rate of a medium flowing in a pipeline rests, for example, on having the medium flow through the measuring tube inserted into the pipeline and oscillating during operation laterally to a measuring tube axis, whereby Coriolis forces are induced in the medium
Implementation Method 4
a sensor arrangement for sensing vibrations of the at least one measuring tube and for delivering oscillation measurement signals representing oscillations of the measuring tube
Data Source
AI summary
The measuring device comprises, for measuring multi phase mixture, a vibratory-type transducer and a measuring device electronics electrically coupled with the vibratory-type transducer. The transducer includes at least one measuring tube inserted into the course of the pipeline. An exciter arrangement acts on the measuring tube for causing the at least one measuring tube to vibrate. A sensor arrangement senses vibrations of the at least one measuring tube and delivers at least one oscillation measurement signal representing oscillations of the measuring tube. Further, the measuring device electronics delivers an excitation current driving the exciter arrangement. The measuring device is adapted to compensating measurement errors, induced due to the presence of multi phase mixture, based on a movin resonator model (MRM).