Oscillator Eigenfrequency Normalization for Density Variation Analysis

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing measuring devices face challenges in analyzing density variations of multiphase media, particularly inhomogeneous gas-containing liquids, as they require multiple measurements and complex algorithms to determine free bubble concentrations, making the analysis device-dependent and cumbersome.

Innovation Solution

A measuring device with an oscillator having at least one oscillatable measuring tube, an exciter, and an oscillation sensor, along with an operating-evaluating circuit that registers and normalizes eigenfrequency variations to determine density variations independently of the device type, using functions proportional to eigenfrequency variations and modal stiffness, enabling reliable characterization of medium inhomogeneity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple measurements and complex algorithms are used to determine free bubble concentrations, then measurement precision is improved, but device complexity increases and ease of operation deteriorates

Engineering Contradiction:

Improvedetermination of free bubble concentrationsVSAvoidcomplexity of measurement process

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention changes the evaluation parameter from raw frequency variation to normalized frequency variation (df/f0), which inherently accounts for device-specific characteristics. This parameter transformation allows different device types to produce comparable results without requiring complex device-specific algorithms, thus reducing device complexity while maintaining measurement precision for free bubble concentration determination

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If device-specific algorithms are used for each measuring device type, then measurement precision is improved, but adaptability deteriorates

Engineering Contradiction:

Improvedensity variation analysisVSAvoidindependence from measuring device form

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The invention creates a universal evaluation method based on normalized frequency variation (df/f0) that can be applied across different measuring device types and oscillation modes. The normalization process makes the evaluation independent of device-specific characteristics such as oscillation frequency and mode, enabling the same algorithm to work universally for density variation analysis regardless of the particular form of the measuring device

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If eigenfrequency variations are analyzed without normalization, then ease of operation is improved, but measurement precision deteriorates due to device dependency

Engineering Contradiction:

Improvesimplicity of analysisVSAvoiddensity variation determination

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The invention transforms the evaluation parameter from absolute eigenfrequency variation (df) to relative normalized variation (df/f0). This parameter change maintains operational simplicity by using a straightforward calculation while dramatically improving measurement precision and device independence. The normalization divides the frequency variation by the eigenfrequency itself, creating a dimensionless parameter that eliminates device-specific scaling effects

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

The solution allows for a simpler and more independent analysis of density variations, providing consistent results across different measuring devices by normalizing eigenfrequency variations, effectively characterizing medium inhomogeneity and enabling reliable detection of free bubbles, regardless of the oscillation mode used.

Implementation Method 1

the oscillator has at least one oscillatory mode, whose eigenfrequency depends on density p of the medium

Methodology Applied

Scientific EffectEigenfrequency dependence on density:

Implementation Method 2

an exciter for exciting the oscillatory mode

Methodology Applied

Scientific EffectMechanical vibration: Vibration

Implementation Method 3

at least one oscillation sensor for registering oscillations of the oscillator

Methodology Applied

Scientific EffectVibration detection: Vibration

Data Source

PatentUS20250093189A1Measuring device for determining the density, the mass flow rate and/or the viscosity of a flowable medium, and method for operating same

Publication Date: 2025.03.20 ENDRESS HAUSER FLOWTEC AG

AI summary

A measuring device for determining density, mass flow rate and/or viscosity of a flowable medium includes: an oscillator including at least one oscillatable measuring tube for conveying the medium, and having at least one oscillatory mode, whose eigenfrequency depends on density of the medium; an exciter for exciting the oscillatory mode; at least one oscillation sensor for registering oscillations of the oscillator; and an operating-evaluating circuit, which is adapted to supply the exciter with an excitation signal, to register signals of the oscillation sensor, based on the signals of the oscillation sensor to ascertain current values of the eigenfrequency of the oscillator as well as variations of the eigenfrequency, and to determine a value characterizing density variations of the medium, wherein the value depends on a function, which is proportional to the variation of the eigenfrequency and has an eigenfrequency dependent normalization.