Coriolis Mass Flowmeter Density Accuracy via Multi-Frequency Oscillation
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Solution Overview
Problem
Conventional Coriolis-type mass flowmeters face inaccuracies in density measurements of flowing media due to reliance on natural frequency, which is influenced by thermal and mechanical factors, leading to unreliable results.
Innovation Solution
A method that evaluates oscillations of the measuring tube at multiple frequencies and modes using a physical-mathematical model, incorporating the dynamics of the measuring tube and additional components, to determine medium density, accounting for elasticity changes and process conditions like temperature and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If density is determined using natural frequency of the measuring tube, then the measurement can be obtained, but the accuracy is insufficient due to thermal and mechanical factor influences
Solution Approach 1:
The patent segments the density determination process into multiple independent measurement components: natural frequency measurement, thermal variable measurement (temperature, voltage), and mathematical modeling. By separating these measurements and processing them independently through a physical-mathematical model, the system eliminates the harmful influence of thermal and mechanical factors on the final density accuracy.
Solution Approach 2:
The patent introduces a physical-mathematical model as an intermediary between the raw measurement data (natural frequency, temperature, voltage) and the final density value. This model acts as a mediator that processes the measurements while compensating for thermal and mechanical effects, thereby improving both accuracy and reliability of density determination.
2Measurement precision
If the physical-mathematical model includes additional components like support pipe and suspension, then the representation of the mass flowmeter system becomes more complete, but the processing effort increases
Solution Approach 1:
The patent applies partial action by selectively including only those additional components (support pipe, suspension) that have significant influence on the oscillation characteristics. The physical-mathematical model incorporates these components to the extent necessary for accurate density measurement, avoiding unnecessary complexity while maintaining measurement precision.
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 enhances the accuracy of density measurements by decoupling the effective elastic rigidity from the density calculation, providing a more comprehensive representation of the mass flowmeter system and improving measurement reliability.
Implementation Method 1
a mass flowmeter that employs the Coriolis principle and encompasses a measuring tube through which flows a medium, whereby the measuring tube is energized to oscillate at a minimum of two mutually different frequencies and/or in at least two mutually different natural oscillating modes
Implementation Method 2
by means of the recorded oscillatory response pattern of the measuring tube, the characteristic values of the mass flowmeter such as its zero point and its sensitivity are determined
Implementation Method 3
determine the density of the flowing medium by way of the natural frequency in the first oscillating mode of the vibrating measuring tube
Data Source
AI summary
A method for operating a mass flowmeter that employs the Coriolis principle and through which flows a medium, wherein the mass flowmeter incorporates a measuring tube that can be stimulated to oscillate, the measuring tube is stimulated to oscillate at a minimum of two mutually different frequencies and/or in at least two mutually different natural oscillating modes, and the resulting oscillations of the measuring tube are recorded. The density of the medium flowing through the measuring tube is determined by evaluating the acquired oscillations of the measuring tube on the basis of a physical-mathematical model for the dynamics of the mass flowmeter. In this fashion, highly accurate measurements are obtained for determining the density of the medium flowing through the measuring tube.