Vibrating Tube Viscosity Measurement Across Multiple Shear Rates
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Solution Overview
Problem
Existing devices for measuring fluid viscosity fail to determine shear rate-dependent viscosities and cannot distinguish between Newtonian and non-Newtonian fluids, nor quantify shear rate dependence of viscosity.
Innovation Solution
A device that measures viscosity based on at least two viscosity measurements at different shear rates, determines a viscosity profile, and identifies whether a fluid is Newtonian, shear-thinning, or shear-thickening by comparing measurements with reference values and calibration data, using excitation of multiple vibration modes to analyze damping and frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single vibration mode is used for viscosity measurement, then the measurement is simple, but the ability to determine shear rate-dependent viscosity and distinguish fluid types is lost
Solution Approach 1:
The patent divides the viscosity measurement into multiple discrete shear rate measurements by exciting different vibration modes (e.g., first, second, and third modes corresponding to different frequencies). Each mode provides a viscosity measurement at a specific shear rate, allowing the construction of a complete viscosity-shear rate profile that reveals fluid type and shear rate dependence.
Solution Approach 2:
The patent transitions from single-point viscosity measurement to multi-dimensional viscosity characterization by adding the shear rate dimension. By measuring viscosity at multiple shear rates through different vibration modes, the system creates a viscosity profile that provides comprehensive fluid rheological information beyond what a single measurement can deliver.
2Measurement precision
If multiple vibration modes are excited to determine shear rate-dependent viscosity, then viscosity profile accuracy improves, but device complexity and measurement time increase
Solution Approach 1:
The patent makes the single measuring tube serve multiple functions by exciting it in different vibration modes. The same physical tube can be excited in first, second, third, or higher modes to obtain viscosity measurements at different shear rates, eliminating the need for multiple separate measurement devices or complex probe configurations.
Solution Approach 2:
The patent changes the operational parameters of the measuring tube by varying the excitation frequency and vibration mode. By controlling the tube to vibrate at different frequencies (corresponding to different modes), the system varies the effective shear rate experienced by the fluid, enabling multi-point viscosity characterization without changing the physical measurement geometry.
3Measurement precision
If multiple vibration modes are used to measure viscosity at different shear rates, then fluid type identification improves, but measurement time increases
Solution Approach 1:
The patent employs periodic excitation of different vibration modes in a systematic sequence. The measuring tube is excited in the first mode, then the second mode, then the third mode, with each excitation being a periodic vibration event. This structured periodic measurement approach efficiently collects multiple viscosity data points in a time-organized manner, enabling rapid fluid type identification.
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
Enables accurate determination of shear rate-dependent viscosities, differentiation between fluid types, and detection of viscosity deviations, with enhanced measurement accuracy and correction for density and mass flow errors.
Implementation Method 1
a pipe section (7) of a measuring tube (5) through which the fluid flows is excited to vibrations of a useful vibration mode and the viscosity of the fluid flowing through it is determined on the basis of the damping of the resulting vibration
Implementation Method 2
the viscosity of the fluid is determined on the basis of the damping of the resulting vibration which depends on the viscosity
Implementation Method 3
exciting the pipe at a first frequency to vibrate a first bending-displacement mode, exciting the pipe at a second frequency to vibrate the first bending-displacement mode
Implementation Method 4
DE 10 2004 021 690 A1 describes a Coriolis mass flow meter designed for use in applications where parameters of inhomogeneous fluids
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An apparatus for measuring viscosities of fluids is described, having a measuring system (1) with at least one measuring tube (5) which, during the measuring operation, is filled with a fluid or is flowed through by the fluid and which has at least one tube portion (4, 7) which is excited to perform vibrations, having an exciter device (3) for exciting at least two useful vibration modes having different frequencies, at each of which at least one of the tube portions (4, 7) is excited to perform vibrations, in particular resonance vibrations, of the respective useful vibration mode, having a measuring device (9) which is designed such that, for each of the useful vibration modes excited during the measuring operation, said measuring device determines a frequency and an attenuation, in particular a frequency, an amplitude and an attenuation, of the resultant vibration of at least one pipe portion (4, 7) excited to perform vibrations in the respective useful vibration mode, and having an evaluating device (15) which is designed such that, on the basis of calibration data stored in a memory (17), the evaluating device determines a measured shear rate value and a measured viscosity value for the individual useful vibration modes excited during the measuring operation on the basis of the frequency determined during the excitation thereof and the attenuation, in particular the frequency, the amplitude and the attenuation, of the resultant vibration, wherein the measured viscosity value corresponds to the dynamic viscosity of the fluid at a steady shear rate corresponding to the shear rate value.