Flexural Oscillator Density Measurement with Vibration Damping Correction
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Solution Overview
Problem
Existing methods for determining the density of liquids using flexural oscillators are affected by inhomogeneities such as air or gas inclusions, leading to inaccurate measurements, which require manual visual inspection and increased effort.
Innovation Solution
The method employs the relative difference between the fundamental and harmonic vibrations, along with vibration damping values, to automatically detect and correct for inhomogeneities, ensuring accurate density measurements by analyzing the functional dependence of these variables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual visual inspection is used to detect inhomogeneities, then measurement accuracy can be maintained, but work effort and expense increase
Solution Approach 1:
The system performs self-diagnosis by automatically detecting inhomogeneities through vibration analysis. The flexural oscillator itself generates the vibrations and the evaluation unit analyzes the vibration characteristics to detect gas inclusions, eliminating the need for external manual visual inspection while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces manual visual inspection with an automated mechanical vibration-based detection system. Instead of visually examining the liquid sample, the system uses vibration analysis of the flexural oscillator to detect inhomogeneities, substituting mechanical vibration measurement for manual optical inspection.
2Measurement precision
If flexural oscillator is filled with liquid sample at least up to clamping points, then constant volume participates in vibration, but overfilling beyond clamping points is irrelevant for measurement
Solution Approach 1:
The system extracts only the relevant vibration information from the flexural oscillator by analyzing vibrations at specific locations or modes that are sensitive to liquid density but insensitive to filling level variations. This allows the system to ignore overfilling conditions while maintaining measurement precision.
Solution Approach 2:
The patent uses changes in vibration parameters (frequency, amplitude, damping) of the flexural oscillator to detect inhomogeneities. By monitoring how these parameters change during vibration, the system can detect gas inclusions without needing to precisely control or monitor the filling level beyond the clamping points.
3Measurement precision
If viscosity correction is applied to compensate for sample viscosity, then density measurement accuracy improves, but measurement complexity increases
Solution Approach 1:
The system incorporates feedback by continuously monitoring vibration characteristics and comparing them against expected values. The evaluation unit analyzes the vibration data in real-time to detect inhomogeneities and can trigger warnings or reject measurements, providing feedback control that maintains accuracy without requiring complex manual intervention.
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 enables precise and automated detection of invalid density values caused by inhomogeneities, improving measurement accuracy and reducing manual inspection requirements.
Implementation Method 1
the sample is placed in a hollow, U-shaped tube that forms the flexural oscillator, which is electronically excited to subject it to undamped vibration. The natural frequency of the flexural oscillator depends on the mass of the sample.
Implementation Method 2
The two legs of the U-shaped oscillator tube form spring elements of the flexural oscillator.
Implementation Method 3
along with vibration damping values, to automatically detect and correct for inhomogeneities
Data Source
AI summary
The actual density of liquids is determined with a flexural oscillator that is excited at two different natural vibrations. The presence of air/gas inclusions or other inhomogeneities in a liquid is detected and their influence can be eliminated. In an initial step, the periods of the inherent vibrations and of at least one vibration damping value of the natural vibrations are determined for liquids having different densities ρ and viscosities. Liquid densities as well as the difference between them and between the vibration damping values are determined from this. An inclusion-free curve (KB) which reflects the functional dependence F(ρδ) between the relative density differences and the vibration damping differences is calculated and the exact function determined; i.e. the gas/air inclusion-free curve (KB) is expanded by introducing a deviation bandwidth (ab) to form an inclusion-free curve area (KF), which is stored. The functional value F(ρδ) of the liquid to be tested is determined and a check is performed to ascertain whether it is within the inclusion-free curve area and whether the resulting value of the density ρ is or is not applicable to the liquid being tested.