Coriolis Mass Flow Meter Nonlinear Disturbance Detection

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Solution Overview

Problem

Existing Coriolis mass flowmeters struggle to detect nonlinear disturbances, such as misalignment or mechanical detachment of vibration components, which affect the vibration behavior and are not easily detectable using existing methods.

Innovation Solution

The method involves determining expected values of amplitude and phase at specific evaluation frequencies corresponding to the excitation frequency and its harmonics, comparing these with actual measurement signals, and triggering alerts if deviations exceed predefined limits, while analyzing the comparison measurement signal within well-defined frequency ranges to detect non-linear disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing vibration monitoring methods are used in Coriolis mass flowmeters, then the device can operate normally, but nonlinear disturbances such as misalignment or mechanical detachment of vibration components cannot be detected

Engineering Contradiction:

Improvedetection capabilityVSAvoidnonlinear disturbance detection

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent determines expected values of amplitude and phase at evaluation frequencies (including harmonics) before comparing them with actual measurement signals. This preliminary establishment of reference values enables the detection of nonlinear disturbances by identifying deviations from expected behavior, allowing the system to proactively detect misalignment or mechanical detachment issues.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extends the analysis from only the fundamental excitation frequency to include harmonic frequencies (multiples of the excitation frequency). By evaluating the signal at multiple frequency dimensions (fundamental frequency and its harmonics), the system can detect nonlinear disturbances that manifest as harmonic components, thereby adding a frequency dimensionality to the detection capability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If the measuring tube is excited in the fundamental resonance mode, then the mass flow measurement can be performed, but nonlinear disturbances affect the vibration behavior and cannot be easily detected

Engineering Contradiction:

Improvemass flow measurementVSAvoidvibration behavior monitoring

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent continuously compares the actual vibration signal characteristics (amplitude and phase at fundamental and harmonic frequencies) with pre-determined expected values. This feedback mechanism allows the system to monitor the vibration behavior of the measuring tube and detect deviations caused by nonlinear disturbances, ensuring reliable operation while maintaining productive mass flow measurement.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent monitors changes in vibration parameters (amplitude and phase) at both the fundamental excitation frequency and its harmonics. By tracking these parameter variations and comparing them against expected values, the system can detect nonlinear disturbances that alter the vibration behavior of the measuring tube during mass flow measurement operations.

Inventive Principle:

Principle #35Parameter changes

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 allows for easy monitoring of the Coriolis mass flowmeter's state and timely detection of faults, ensuring reliable operation by identifying non-linear disturbances that may not be detectable with existing methods.

Implementation Method 1

the vibration generator causes the measuring tube to oscillate harmonically with the excitation frequency f0 and the excitation amplitude A0

Methodology Applied

Scientific EffectHarmonic oscillation: Harmonic Oscillator

Implementation Method 2

If a medium flows through the measuring tube, the Coriolis acceleration acts on the medium, which ultimately results in a phase difference between the vibrations on the inlet and outlet sides of the measuring tube

Methodology Applied

Scientific EffectCoriolis force: Coriolis Force

Implementation Method 3

the first and the second vibration sensor detecting the vibration of the measuring tube

Methodology Applied

Scientific EffectVibration detection: Vibration

Data Source

PatentEP3327406B1Method for operating a coriolis mass flow meter and coriolis mass flow meter

Publication Date: 2020.06.17 KROHNE MESSTECHNICK GMBH & CO KG

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AI summary

A method (1) for operating a Coriolis mass flow meter (2) is described and illustrated, wherein the Coriolis mass flow meter (2) comprises at least one measuring tube (3), at least one vibration generator (4), at least two vibration sensors (5), and at least one control and evaluation unit (6), wherein the vibration generator (4) and the vibration sensors (5) are arranged on the measuring tube (3), wherein the measuring tube (3) is permeable to a medium, wherein the vibration generator (4) sets the measuring tube (3) into a harmonic oscillation with the excitation frequency f0 and the excitation amplitude A0, wherein the first and the second vibration sensors (5) detect the oscillation of the measuring tube (3).wherein the first vibration sensor (5) transmits the vibration as the first measurement signal to the control and evaluation unit (6) and wherein the second vibration sensor (5) transmits the vibration as the second measurement signal to the control and evaluation unit (6) and wherein at least one comparison measurement signal (10) is determined from the first measurement signal and/or the second measurement signal.