Coriolis Flowmeter Density Sensitivity Rate Monitoring
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Solution Overview
Problem
Existing methods for operating Coriolis mass flowmeters do not effectively detect changes in system behavior, such as wear or deposits, which can affect the accuracy of density measurements and dynamic behavior, especially due to temperature variations.
Innovation Solution
A method that calculates the rate of change of density sensitivity by comparing the current density sensitivity with the calibration sensitivity, using a prediction algorithm that does not depend on detected vibrations, to generate a deviation signal indicating changes in the Coriolis mass flowmeter's behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If density sensitivity is determined using detected vibrations of the measuring tube, then measurement information is obtained, but system behavior changes such as wear or deposits cannot be detected
Solution Approach 1:
The patent segments the density sensitivity determination into two independent components: (1) calibration density sensitivity determined from vibrations at a first temperature, and (2) current density sensitivity determined from vibrations at a second temperature. This segmentation allows separate evaluation of measurement data and system state, enabling detection of system behavior changes while maintaining measurement precision.
Solution Approach 2:
The patent introduces temperature as an intermediary parameter to distinguish between legitimate density variations (due to temperature changes) and illegitimate system changes (due to wear or deposits). By comparing density sensitivities at different temperatures and analyzing the rate of change, the system can identify when changes are due to normal thermal effects versus when they indicate problematic system behavior.
2Ease of manufacture
If calibration is performed at a single temperature, then calibration is simple, but temperature variations cause inaccuracies in density measurements
Solution Approach 1:
The patent performs preliminary calibration at a first temperature to establish calibration density sensitivity, then uses this calibration to correct measurements taken at different temperatures. The system calculates the rate of change of density sensitivity with temperature and uses this information to compensate for temperature variations, maintaining measurement precision without requiring recalibration at every temperature.
Solution Approach 2:
The patent explicitly accounts for parameter changes (temperature variations) by determining density sensitivity at multiple temperatures and calculating the rate of change. This allows the system to adapt to temperature changes while maintaining calibration accuracy, avoiding the need for complex multi-temperature calibration procedures.
3Reliability
If multiple density sensitivity measurements are taken at different temperatures, then system behavior can be monitored, but measurement complexity increases
Solution Approach 1:
The patent extracts the essential information needed for system behavior monitoring by focusing on the rate of change of density sensitivity with temperature. Rather than analyzing all possible measurement parameters, the system specifically extracts the temperature coefficient of density sensitivity, which serves as a reliable indicator of system behavior while keeping the measurement procedure manageable.
Solution Approach 2:
The system uses its own measurement capabilities to perform self-diagnosis by monitoring changes in density sensitivity characteristics. The Coriolis flow meter uses its vibration detection system to measure density sensitivity at different temperatures and automatically determines whether system behavior has changed, eliminating the need for external monitoring equipment or complex manual testing procedures.
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 the detection of changes in the Coriolis mass flowmeter's behavior by determining the measurement rate of change and prediction rate of change in density sensitivity, enabling early detection of structural changes or wear, thus ensuring accurate operation and maintaining measurement quality.
Implementation Method 1
a Coriolis mass flowmeter (2) having at least one measuring tube (3) through which a medium flows, the measuring tube (3) being excited to oscillate in at least one frequency and/or in at least one natural mode
Implementation Method 2
the resulting oscillations of the measuring tube (3) being recorded and the density d of the medium is determined by evaluating the recorded vibrations
Data Source
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AI summary
A method (1) for operating a Coriolis mass flow meter (2) is presented and described, wherein the Coriolis mass flow meter has at least one measuring tube (3) through which a medium flows, the measuring tube (3) is excited to oscillate at at least one frequency and/or at least one mode shape, the resulting oscillations of the measuring tube (3) are detected, and the density d of the medium is determined by evaluating the detected oscillations. Detection of the state and changes of state of the Coriolis mass flow meter is achieved by determining a calibration density sensitivity Ed,k(Tk) of the Coriolis mass flow meter (2) at a calibration temperature Tk using the detected oscillations of the measuring tube (3) (100).by determining a density sensitivity Ed(T) of the Coriolis mass flow meter (2) at a temperature T that differs from the calibration temperature Tk using the detected vibrations of the measuring tube (3) (110), by determining a measurement rate of change rm of the density sensitivity Ed from the calibration density sensitivity Ed,k(Tk) determined using the detected vibrations and the density sensitivity Ed(T) at temperature T (120), by calculating a prediction rate of change rp of the density sensitivity using a prediction algorithm (130) that depends on the temperature T that differs from the calibration temperature Tk, but does not depend on the detected vibrations of the measuring tube (3), and by generating a deviation signal when the measurement rate of change rm deviates from the prediction rate of change rp by a predetermined amount (140).