Coriolis Flowmeter Magnet Temperature Compensation
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Solution Overview
Problem
Coriolis mass flowmeters face challenges in achieving precise measurement results due to temperature-dependent physical parameters, such as spring stiffness, which are not adequately compensated by existing methods that rely solely on measuring tube temperature.
Innovation Solution
Determining the electrical impedance of the coil and using it to calculate temperature-dependent state variables, which accounts for the temperature influence on permanent magnets, allowing for improved compensation of temperature effects without direct magnet temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only measuring tube temperature is measured for compensation, then the device complexity is low, but the measurement precision deteriorates due to inadequate temperature compensation
Solution Approach 1:
The patent uses the coil's electrical impedance as an intermediary parameter to indirectly determine the permanent magnet temperature. Instead of directly measuring magnet temperature or adding separate temperature sensors, the method measures the coil impedance (which varies with temperature) and uses this as a proxy to determine magnet temperature and compensate for its effects on state variable measurements.
Solution Approach 2:
The patent replaces direct temperature measurement mechanisms with an electrical measurement approach. By measuring the electrical impedance of the coil instead of using temperature sensors to directly measure magnet temperature, the system achieves temperature compensation through electrical properties rather than mechanical/thermal sensing.
2Measurement precision
If direct magnet temperature measurement is implemented, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
The coil's electrical impedance serves as an intermediary that correlates with magnet temperature. The patent establishes that coil impedance varies with temperature in a predictable manner, allowing the impedance measurement to substitute for direct magnet temperature measurement while maintaining compensation accuracy.
Solution Approach 2:
The system uses its own existing components (the coil already present in the vibration generator) to perform the temperature indication function. The coil serves dual purposes: generating vibrational force and indicating temperature through its impedance, eliminating the need for separate temperature sensing components near the magnet.
3Reliability
If temperature-dependent state variables are calculated without coil impedance data, then the ease of operation is high, but the reliability deteriorates due to un compensated magnet temperature effects
Solution Approach 1:
The patent implements a feedback mechanism where the measured coil impedance is continuously used to determine magnet temperature and adjust the calculation of state variables. The evaluation device uses the impedance-derived temperature information to compensate for magnet temperature effects, creating a closed-loop system that maintains reliability.
Solution Approach 2:
The coil impedance acts as an intermediary information source that provides temperature-related data to the evaluation device. This intermediary measurement enables the system to account for magnet temperature effects without requiring direct magnet temperature sensing or complex additional measurements.
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 enhances the accuracy of state variable determination and monitoring of the Coriolis mass flowmeter's condition, enabling better compensation for temperature-related effects and providing a reliable indicator for the magnet temperature, thus improving measurement precision and device monitoring.
Implementation Method 1
the permanent magnet is arranged in the area of influence of the coil in such a way that the magnetic field generated when the coil is energized interacts with the magnetic field of the permanent magnet and corresponding forces act on the coil and permanent magnet
Implementation Method 2
the detected impedance of the coil is a reliable indicator of the temperature of the coil and of the temperature of the permanent magnet provided in the immediate vicinity
Implementation Method 3
The reason for the increasing different vibration components resulting with increasing mass flow on the inlet and outlet side are differently directed Coriolis forces on the flowing medium on the inlet and outlet side
Data Source
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AI summary
A method for operating a Coriolis mass flow meter (1) is described and illustrated, wherein the Coriolis mass flow meter (1) comprises at least one measuring tube (2), at least one vibration generator (3), at least two vibration sensors (4) and at least one evaluation device (5), wherein the vibration sensors (4) and/or the vibration generator (3) each comprise at least one permanent magnet (6) and at least one coil (7), wherein the vibration generator (3) excites the measuring tube (2) to vibrate, wherein the vibration sensors (4) detect the vibrations of the measuring tube (2), wherein the temperature of the measuring tube (2) is determined, and wherein the evaluation device (5) processes the detected vibration signals and determines state variables of the Coriolis mass flow meter (1).A method for operating a Coriolis mass flow meter (1) which has a higher accuracy in determining state values is realized by determining the electrical impedance of the coil (7) of the vibration generator (3) and/or the electrical impedance of at least one coil (7) of the vibration sensor (4) and by the evaluation device (5) calculating at least one temperature-dependent state variable D, wherein the temperature-dependent state variable D is corrected from the temperature of the measuring tube (2) with the determined impedance of the coil (7).