Coriolis Flow Meter Gas Fraction Detection via Density Segmentation

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Solution Overview

Problem

Coriolis mass flowmeters face challenges in accurately measuring gas content in multi-phase flows, leading to reduced measurement accuracy and potential operational disruptions due to gas inclusions, which existing methods struggle to quantify reliably.

Innovation Solution

A method involving a control and evaluation unit that determines the density of gasless and gas-containing media, calculating the gas volume fraction using the difference in densities, and outputting this information for further processing or display, allowing for continuous monitoring of gas presence and quantity in the medium flowing through the Coriolis mass flowmeter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If gas inclusions are present in the medium flowing through the Coriolis mass flow meter, then the measurement accuracy is reduced and operational reliability deteriorates, but the ability to handle multi-phase flows is improved

Engineering Contradiction:
Improveability to handle multi-phase flowsVSAvoidmeasurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The invention segments the measurement process into distinct phases: first determining the density of the gas-free medium, then measuring the density of the actual medium flowing through the tube, and finally calculating the gas volume fraction by comparing these values. This segmentation allows the system to handle multi-phase flows by separately characterizing the gas and liquid components, thereby maintaining measurement accuracy while improving adaptability to varying flow conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention utilizes changes in density as a key parameter to detect and quantify gas inclusions. By monitoring the density of the medium flowing through the Coriolis mass flow meter and comparing it to the known density of the gas-free medium, the system can calculate the gas volume fraction. This parameter-based approach enables accurate measurement in multi-phase flows by focusing on the physical property that changes most significantly with gas content.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If existing two-phase flow detection methods are used, then gas presence can be detected, but quantitative information on gas fraction cannot be reliably obtained

Engineering Contradiction:
Improvereliability of gas detectionVSAvoidquantitative gas fraction information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The invention implements a feedback mechanism where the measured density of the flowing medium is continuously compared to the predetermined density of the gas-free medium. This comparison provides feedback that is used to calculate the gas volume fraction, thereby converting qualitative detection of gas presence into quantitative measurement of gas fraction. The feedback loop ensures reliable detection while capturing the exact amount of gas in the flow.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention performs preliminary determination of the gas-free medium density before actual measurement begins. This preliminary action establishes a reference value that enables subsequent quantitative calculation of gas fraction. By preparing this reference information in advance, the system can reliably detect gas presence and simultaneously provide accurate quantitative information about the gas fraction without loss of measurement data.

Inventive Principle:
Principle #10Preliminary action

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 provides quantitative information on the gas fraction in the medium, enabling improved measurement accuracy and operational reliability by distinguishing between gas-free and gas-containing flows, thus addressing the limitations of existing two-phase flow detection methods.

Implementation Method 1

The operation of Coriolis mass flow meters is based on the fact that the mass of the medium acts back on the wall of the measuring tube due to the Coriolis inertial force caused by two orthogonal movements – that of the flow and that of the measuring tube.

Methodology Applied
Scientific EffectCoriolis effect: Coriolis Force

Implementation Method 2

at least one measuring tube through which a medium flows is excited to oscillate by a vibration generator

Methodology Applied
Scientific EffectOscillation: Vibration

Implementation Method 3

at least two vibration sensors... By detecting these characteristics of the oscillations of the Coriolis measuring tube when the medium is flowing through it (phase shift between the inlet and outlet oscillations), the mass flow rate through the measuring tube can be determined with high accuracy.

Methodology Applied
Scientific EffectVibration detection: Vibration

Implementation Method 4

In such an electromagnetic drive, an electric current flows through a coil as the electrical excitation signal, and this coil current, in conjunction with the coil, directly exerts a force on the measuring tube.

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP3628983B1Method for determining the gas content in a medium flowing through a coriolis mass flow meter and coriolis mass flow meter
Publication Date: 2023.03.22 KROHNE MESSTECHNICK GMBH & CO KG
  • EP3628983B1 patent drawingFigure 1
  • EP3628983B1 patent drawingFigure 2a~3
  • EP3628983B1 patent drawingFigure 4~5

AI summary

A method (1) for determining the gas fraction in the medium (3) flowing through a Coriolis mass flow meter (2) is presented and described, wherein the Coriolis mass flow meter (2) comprises at least one measuring tube (4), at least one vibration generator (5), at least two vibration sensors (6), and at least one control and evaluation unit (7), wherein the method is characterized in that in a ρ100 step (8) the density value ρ100 of the gas-free medium is determined, that in a ρmess step (9) the density value ρmess of the medium (3) flowing through the measuring tube (4) is measured, that in a GVQ step (10) a measure GVQ for the gas fraction of the medium (3) flowing through the measuring tube (4) is calculated using the density value ρ100 and the density value ρmess, and that the measure GVQ for the gas fraction of the medium (3) flowing through the measuring tube (4) is determined by the The flowing medium (3) is discharged from the measuring tube (4).