Flexural Vibrator Filling Quality Detection via Viscosity-Damping Correlation

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Solution Overview

Problem

Existing flexural vibrators face challenges in detecting gas bubbles during fluid filling, which can lead to incorrect measurement results due to changes in resonant frequency and oscillation quality, and existing methods lack effective means to ensure accurate filling quality assessment.

Innovation Solution

A method and device utilizing an adjustment curve or table that relates dynamic viscosity to damping parameters of the oscillating tube, allowing for the determination of filling quality by comparing measured viscosity and damping values, with a focus on detecting deviations indicative of filling errors through a z-score analysis and tolerance bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If gas bubbles are present in the sample liquid during filling, then the resonance frequency changes, but the measurement accuracy deteriorates due to incorrect results

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidgas bubbles
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by performing a filling quality check before the actual density measurement. The method evaluates the filling state by analyzing the relationship between damping and quality factor during the filling process, allowing bubbles to be detected and the filling to be corrected before measurement begins, thus preventing measurement errors caused by bubbles

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring the relationship between damping and quality factor during filling, comparing it against reference values or ranges. When deviations indicating bubble presence are detected, the system provides feedback to stop filling or alert the operator, enabling real-time correction to maintain measurement accuracy

Inventive Principle:
Principle #23Feedback

2Reliability

If the filling quality is not monitored, then the device complexity is reduced, but the reliability of measurement results deteriorates

Engineering Contradiction:
Improvefilling qualityVSAvoidmonitoring system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by using the existing oscillating system to serve multiple functions: both density measurement and filling quality monitoring. The same oscillation parameters (quality factor and damping) used for density measurement are also utilized to assess filling quality, eliminating the need for separate monitoring hardware and reducing overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements self-service by enabling the oscillating system to automatically monitor its own filling quality through analysis of its inherent oscillation characteristics. The system uses its own quality factor and damping measurements to detect bubbles and assess filling state without requiring external monitoring equipment, thereby maintaining reliability while minimizing added complexity

Inventive Principle:
Principle #25Self-service

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 simplifies bubble detection, reduces error, and enables online monitoring of filling quality by correlating dynamic viscosity with damping parameters, ensuring accurate density measurements and prompt identification of filling errors.

Implementation Method 1

The natural frequency of the U-shaped oscillator tube is influenced only by that part of the sample that actually participates in the vibration

Methodology Applied
Scientific EffectNatural frequency vibration: Harmonic Oscillator

Implementation Method 2

the legs of the U-shaped tube can be excited against each other. This results in specific resonant frequencies for the oscillator, at which the system preferentially oscillates

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

gas bubbles in the sample liquid not only cause a change in the resonance frequency, but also a change in the quality factor of the vibration system

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 4

a change in the quality factor of the vibration system

Methodology Applied
Scientific EffectQuality factor: Damping

Data Source

PatentEP3006916B1Method and device for determining the filling quality of an oscillator
Publication Date: 2023.05.24 ANTON PAAR GMBH
  • EP3006916B1 patent drawingFigure 1
  • EP3006916B1 patent drawingFigure 2~3
  • EP3006916B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for determining the filling quality of a flexural vibrator, the vibrator tube of which is permeated by the measuring fluid. According to the invention, the relationship between the viscosity-dependent density of the measuring fluid and the quality and/or damping of the vibrator tube, preferably the amplitude and/or phase of a natural frequency, is determined by ascertaining the relationship between the dynamic viscosity and the damping and/or quality of the measuring fluid and creating an adjustment curve or table with these values, which represents the functional relationship between a parameter relevant for the quality and/or damping of the flexural vibrator and the viscosity of the measuring fluid. Furthermore, during the measurement of the measuring fluid with the flexural vibrator, an independent, additional, or...with an additional measuring device, at least one measured value for the dynamic viscosity of the measuring fluid is determined; in the course of measuring the measuring fluid with the oscillating bending device, at least one measured value for the relevant parameter, preferably the density of the measuring fluid, is determined; the function value determined or caused by the obtained measured value for viscosity on the adjustment curve or in the adjustment table corresponds to the function value determined or caused by the obtained measured value for quality and/or damping on the adjustment curve or table; and the result of this comparison is evaluated with regard to the possible presence of a filling error or is used to determine a possible filling error of the oscillating bending device.