Vibrating Meter Q Calculation for Stable Viscosity Measurement
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Solution Overview
Problem
Existing vibrating meters face inaccuracies in viscosity measurements due to fluid density changes, as the measurement of 3 dB bandwidth points at different times leads to oscillating Q values, which are highly sensitive to frequency or time period changes.
Innovation Solution
The method involves measuring and calculating viscosity and density using a vibrating meter that aligns the leading and trailing 3 dB bandwidth measurement points to the same moment in time, either through interpolation or extrapolation, ensuring accurate Q measurements even with fluid density changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the leading and trailing 3 dB bandwidth measurement points are measured at different times, then the measurement process is simpler, but the Q values oscillate due to frequency changes causing measurement inaccuracies
Solution Approach 1:
The patent applies preliminary action by measuring the leading 3 dB bandwidth point first, then using that measurement to determine when to measure the trailing 3 dB bandwidth point. This ensures both measurements are taken at the same moment in time, eliminating oscillations caused by frequency changes while maintaining a systematic measurement process.
Solution Approach 2:
The patent uses feedback by continuously monitoring the vibrational response and using the leading 3 dB bandwidth measurement to dynamically determine the timing of the trailing 3 dB bandwidth measurement. This feedback mechanism ensures both measurements correspond to the same moment in time, stabilizing the Q value calculation against frequency drift.
2Device complexity
If the Q value is calculated using measurements taken at different time points, then the calculation is more straightforward, but frequency or time period changes cause erroneous Q measurements
Solution Approach 1:
The patent performs preliminary measurement of the leading 3 dB bandwidth point, then uses this result to determine the exact moment for measuring the trailing 3 dB bandwidth point. This preliminary action ensures both measurements are synchronized to the same moment in time, eliminating errors from frequency changes while keeping the calculation process manageable.
Solution Approach 2:
The patent implements feedback by using the leading 3 dB bandwidth measurement to dynamically set the timing for the trailing 3 dB bandwidth measurement. This feedback loop ensures both measurements are taken at the same moment in time, significantly improving Q measurement reliability without substantially increasing calculation complexity.
3Measurement precision
If measurements are taken continuously to capture frequency changes, then measurement precision is improved, but the time required for measurement increases
Solution Approach 1:
The patent uses preliminary measurement of the leading 3 dB bandwidth point to determine the optimal timing for the trailing 3 dB bandwidth measurement. This approach captures frequency changes at the critical moment without requiring continuous measurement, achieving high precision while minimizing measurement time.
Solution Approach 2:
The patent employs periodic action by taking measurements at specific intervals determined by the vibrational period. The leading 3 dB bandwidth measurement is taken at one point in the cycle, and the trailing 3 dB bandwidth measurement is taken at the corresponding point in the same cycle, achieving precise Q value measurement without continuous monitoring.
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 stabilizes Q measurements, reducing errors caused by fluid density fluctuations, thereby enhancing the accuracy of viscosity and density calculations.
Implementation Method 1
Vibrating meters may comprise a vibrating element, such as a fork, a cylinder, or a planar resonator, etc. that is exposed to a fluid under test. The member can be vibrated at resonance and the resonant response frequency can be measured.
Implementation Method 2
The resonant frequency of the vibrating element will vary inversely with the density of the fluid that contacts the conduit.
Implementation Method 3
Q is a dimensionless parameter that describes how underdamped an oscillator or resonator is. Viscosity is determined by measuring the quality factor (Q) of the resonance and hence damping of the resonator.
Implementation Method 4
Viscosity is a fluid characteristic that describes flow resistance. A common definition of viscosity is a measure of the internal friction of a fluid.
Data Source
AI summary
A vibrating meter (100) is provided being operable to determine at least one of a viscosity and a density of a fluid therein. The vibrating meter (100) comprises a driver (112), a vibrating element (104) vibratable by the driver (112), and operable to be in contact with the fluid. A vibrating sensor (114) is configured to detect a vibrational response of the vibrating element (104). Meter electronics (118) is configured to send an excitation signal to the driver (112) and to receive the vibrational response and is further configured to measure a first vibrational response point and a second vibrational response point of the vibrational response. The second vibrational response point is one of interpolated and extrapolated from other measured response points. The meter electronics (118) is further configured to calculate a Q of the vibrating element (104) using the first vibrational response point and the second vibrational response point.