U-Tube Densimeter Viscosity Correction via Frequency Ratio
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Solution Overview
Problem
Existing densimeters fail to accurately measure sample density with high precision, particularly when viscosity is a factor, as they do not account for viscosity in their calculations, leading to inaccurate results and requiring multiple measurements.
Innovation Solution
A method that involves injecting a sample into a densimeter's U-tube, applying a synchronized rectangular excitation signal to maintain resonance signal amplitude, and using a correction factor based on viscosity to calculate the actual sample density, accounting for viscosity in the measurement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the standard density measurement method using resonance frequency is used, then the measurement process is simple and fast, but the measurement precision is insufficient when accuracy greater than e−4 g/ml is required due to not accounting for viscosity damping
Solution Approach 1:
The invention changes the measurement parameters by introducing a correction factor based on the ratio between excitation signal frequency and resonance frequency. This allows the system to account for viscosity effects without fundamentally changing the measurement setup, thereby improving density measurement accuracy while maintaining relatively simple device operation
Solution Approach 2:
The invention implements a feedback mechanism where the system continuously monitors the resonance frequency and excitation frequency, calculates their ratio, and applies this as a correction factor to the density measurement. This feedback loop enables automatic compensation for viscosity effects, improving measurement precision without requiring manual intervention or complex additional hardware
2Measurement precision
If multiple measurements with different algorithms are performed to account for viscosity, then the measurement precision improves, but the productivity decreases due to time-consuming multiple measurements
Solution Approach 1:
The invention performs preliminary calibration measurements with fluids of known density and viscosity characteristics to establish the relationship between frequency ratios and density corrections. This preliminary action creates a calibration curve or lookup table that enables rapid correction factor determination during actual measurements, eliminating the need for multiple time-consuming measurements while maintaining high precision
Solution Approach 2:
The invention transforms the measurement approach by using the frequency ratio as a direct parameter to determine the correction factor. This single-parameter method replaces multiple measurement algorithms, allowing the system to achieve high measurement precision through a single measurement while maintaining fast productivity
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 allows for accurate and simultaneous determination of sample density and viscosity correction, enabling precise density calculations without the need for multiple measurements.
Implementation Method 1
causing the U-tube to vibrate at resonance frequency
Implementation Method 2
an electromagnetic excitation winding mounted in a housing of the enclosure
Implementation Method 3
an insulated conductive reading plate maintained at a difference in potential relative to the U-tube and secured to the stopper in a position facing that tube in order to define a capacitor therewith
Data Source
AI summary
A method for the accurate measurement of the density of a sample using a densimeter equipped with a measurement cell, a sample-containing U-tube including a ferromagnetic member, an insulated conductive reading plate maintained at a different potential relative to the U-tube, and an electromagnetic excitation winding. The method includes the steps of transmitting a synchronised rectangular excitation signal continuously to the U-tube to cause the U-tube to vibrate at resonance frequency, the vibration being represented by a sinusoidal resonance signal; determining the resonance frequency from the variations in the voltage at the terminals of the capacitor and deducing an approximate value of the density of the sample; controlling the pulse width of the rectangular excitation signal to maintain a predefined constant amplitude of the resonance signal; and deducing a correction factor dependent on the viscosity of the sample.