Fluid Density Measurement Device Using Oscillation Distribution
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Solution Overview
Problem
Existing devices for measuring fluid density, particularly in heterogeneous mixtures like water-oil emulsions and fluids with occluded gas, face accuracy issues due to resonance frequency variations caused by the surrounding medium properties.
Innovation Solution
A device comprising a mechanical resonator, a driver/receiver unit, and an evaluation unit that determines an oscillation distribution from the resonator's response to actuation, allowing for a resonance frequency estimate and subsequent fluid density calculation, even in complex fluid compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical resonator is used to measure fluid density, then the measurement can be performed continuously in situ, but the resonance frequency varies due to medium properties causing measurement uncertainty
Solution Approach 1:
The patent applies dynamics by transitioning from a static single frequency measurement to a dynamic frequency sweep approach. The system continuously varies the excitation frequency and measures the resonator's response across a range of frequencies, allowing adaptation to changing medium conditions while maintaining measurement accuracy
Solution Approach 2:
The patent uses partial action by measuring the resonator response at multiple frequency points rather than relying on a single resonance frequency measurement. This excessive sampling approach (measuring at more points than the minimum single frequency) provides redundant information that improves reliability in heterogeneous media
2Measurement precision
If a tuning fork resonator is used to prevent oscillation transfer, then the influence of surrounding metal parts is excluded, but the device cannot accurately measure fluids with occluded gas
Solution Approach 1:
The patent achieves universality by designing a measurement system that can accurately measure both homogeneous fluids and heterogeneous fluids (including those with occluded gas). The frequency sweep method with statistical evaluation makes the device adaptable to multiple fluid types without requiring different sensor designs
Solution Approach 2:
The patent applies parameter changes by varying the excitation frequency across a range and using statistical parameters (mean, standard deviation) to characterize the resonator response. This allows the system to accommodate variations in medium properties including the presence of gas bubbles without compromising measurement capability
3Measurement precision
If resonance frequency measurement is performed in heterogeneous mixtures, then density can be determined, but variation in resonance characteristic causes uncertainty in measurement
Solution Approach 1:
The patent implements feedback by using the measured resonator response at each frequency point to inform subsequent measurements. The system builds up a complete frequency response profile and uses statistical evaluation of this data to determine the resonant frequency, providing feedback-based correction for heterogeneous medium effects
Solution Approach 2:
The patent applies preliminary action by performing a complete frequency sweep and statistical evaluation before finalizing the density measurement. The system collects excessive data points across the frequency spectrum and performs preliminary statistical analysis (calculating mean and standard deviation) to identify and compensate for variations caused by heterogeneous media
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 measurement accuracy for fluids with immiscible components and occluded gas by analyzing the oscillation distribution, providing a statistically valid density determination.
Implementation Method 1
the resonance frequency of the mechanical resonator changes
Implementation Method 2
Due to the influence of the added mass of a medium (e.g. a fluid), the resonance frequency of the mechanical resonator changes
Implementation Method 3
sense a response of the mechanical resonator to the actuation
Data Source
Figure 1~2
Figure 3a~3b
AI summary
A device for determining a density of a fluid is described. The devices comprises a mechanical resonator, a driver/receiver unit arranged to provide an actuation to the mechanical resonator, sense a response of the mechanical resonator to the actuation, and provide an output signal representing the response; and an evaluation unit. The evaluation unit of the device is arranged to i. determine an oscillation distribution from the output signal, ii. determine a resonance frequency estimate from the oscillation distribution, and iii. determine the density of the fluid based upon the resonance frequency estimate. The device according to the invention enables a more accurate determination of the fluid density for fluids comprising immiscible components (thus forming a heterogeneous mixture), like a water-oil emulsion, or a fluid with occluded gas.