Coriolis Frequency Tracking via Beat Signal Interference
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Solution Overview
Problem
Coriolis-type mass flowmeters face challenges in accurately determining the frequency of vibrations in a conduit, which affects the measurement of fluid properties like density and mass flowrate, due to interference between major and minor modes of vibration, leading to noise and precision issues.
Innovation Solution
The technique involves inducing motion in a conduit to create a beat signal by interfering major and minor modes of vibration, determining the frequency of this beat signal, and using sensor signals from motion sensors to filter and interpolate data to accurately calculate the Coriolis mode frequency, thereby enhancing the measurement of fluid properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion is induced in a conduit to create vibrations in major and minor modes, then the measurement of fluid properties (density and mass flowrate) is enabled, but interference between the modes causes noise and reduces measurement precision
Solution Approach 1:
The patent applies mechanical vibration by inducing controlled oscillations in the conduit at a driven frequency. The system deliberately creates vibrations in both major and minor modes, then uses signal processing to extract the Coriolis frequency from the resulting beat signal. This approach transforms the harmful vibration interference into a useful measurement mechanism, where the beat frequency between modes provides information about the Coriolis effect caused by fluid flow.
Solution Approach 2:
The patent changes the operating parameters by driving the conduit at a frequency that intentionally creates interference between major and minor vibration modes. By adjusting the driven frequency and analyzing the resulting beat signal frequency, the system can determine the Coriolis mode frequency. This parameter change strategy converts the interference problem into a solution, as the beat frequency contains the Coriolis frequency information needed for accurate fluid measurement.
2Measurement precision
If conventional methods are used to determine vibration frequency, then the process is simple, but the Coriolis mode frequency cannot be accurately isolated from noise without intensive computing
Solution Approach 1:
The patent replaces complex computational methods (such as FFT analysis) with a simpler mechanical signal processing approach. Instead of using intensive computing algorithms to extract the Coriolis frequency from noisy vibration signals, the system uses analog signal manipulation to create a beat signal whose frequency directly reveals the Coriolis mode frequency. This substitution reduces computational complexity while maintaining or improving measurement accuracy.
Solution Approach 2:
The patent introduces an intermediary beat signal as a mediator between the complex vibration interference and the final frequency measurement. By creating a difference signal that manifests as a beat pattern, the system provides a simplified intermediate representation from which the Coriolis frequency can be easily extracted. This intermediary approach avoids the need for direct complex spectral analysis of the original multi-mode vibration signal.
3Measurement precision
If the conduit is driven at a single frequency, then the system is easy to control, but the Coriolis mode frequency determination is affected by noise from mode interference
Solution Approach 1:
The patent employs periodic action by driving the conduit with a sinusoidal signal at a specific driven frequency. This periodic excitation creates consistent, repeatable vibration patterns that generate a predictable beat signal. The regular periodic nature of the driving signal ensures that the interference pattern between modes is stable and can be reliably analyzed to extract the Coriolis frequency, maintaining ease of control while improving 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 method improves the precision and accuracy of fluid property measurements by effectively isolating the Coriolis mode frequency from noise, allowing for precise determination of density and mass flowrate without requiring intensive computing or FFT calculations.
Implementation Method 1
motion is induced in a conduit such that the conduit vibrates in a major mode of vibration having a major amplitude and a minor mode of vibration having a minor amplitude
Implementation Method 2
the minor mode of vibration interferes with the major mode of vibration to cause a beat signal having a frequency related to the first frequency of vibration and the second frequency of vibration
Implementation Method 3
the minor mode of vibration interferes with the major mode of vibration to cause a beat signal
Implementation Method 4
receiving a first sensor signal from a first motion sensor and a second sensor signal from a second motion sensor, the first and second motion sensors configured to sense a motion of the conduit
Implementation Method 5
Coriolis-type mass flowmeters are based on the Coriolis effect, in which material flowing through a rotating conduit is affected by a Coriolis force and therefore experiences an acceleration
Implementation Method 6
the Coriolis reaction force experienced by the traveling fluid mass is transferred to the conduit itself and is manifested as a deflection or offset of the conduit in the direction of the Coriolis force vector
Data Source
AI summary
Motion is induced in a conduit such that the conduit vibrates in a major mode of vibration having a major amplitude and a minor mode of vibration having a minor amplitude. The major amplitude is larger than the minor amplitude, the major mode of vibration has a first frequency of vibration and the minor mode of vibration has a second frequency of vibration, and the minor mode of vibration interferes with the major mode of vibration to cause a beat signal having a frequency related to the first frequency of vibration and the second frequency of vibration. The frequency of the beat signal is determined, and the second frequency of vibration is determined based on the determined frequency of the beat signal.