Geometric Thermal Compensation in Coriolis Flow Meters
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Solution Overview
Problem
Existing Coriolis flow meters face challenges in maintaining accurate mass flow and density measurements due to changes in stiffness and geometry caused by temperature variations, leading to inaccuracies in mass flow rate and density calculations, especially at extreme temperatures.
Innovation Solution
The implementation of meter electronics with a storage system to compute a geometric thermal compensation factor (TFe) that accounts for temperature differences, using a linear or polynomial coefficient of thermal expansion to adjust flow characteristics, such as mass flow rate and density, ensuring accurate measurements across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the flow meter is operated at temperatures different from the reference temperature, then the flow meter can operate in a wider temperature range, but the measurement accuracy deteriorates due to changes in stiffness and geometry
Solution Approach 1:
The patent applies parameter changes by modifying the measurement equations to include temperature-dependent parameters. Specifically, the stiffness parameter k(T) and geometric parameters (length L(T), cross-sectional area A(T)) are changed as functions of temperature, allowing the system to maintain measurement accuracy across varying temperatures by dynamically adjusting for thermal effects in the calculation model
Solution Approach 2:
The patent replaces direct mechanical measurement with a computational approach. Instead of relying solely on mechanical rigidity to maintain accuracy, the system substitutes mechanical stability with mathematical compensation - using temperature measurements and thermal expansion models to calculate and correct for geometric and stiffness changes in real-time, thereby maintaining measurement precision without mechanical constraints
2Measurement precision
If temperature compensation is applied to account for modulus of elasticity changes, then temperature effects are partially compensated, but geometric thermal expansion and contraction are not fully accounted for, leading to residual errors
Solution Approach 1:
The patent segments the temperature compensation into distinct components: one addressing the modulus of elasticity changes and another addressing geometric thermal expansion/contraction. By separating these effects and applying appropriate compensation factors for each (stiffness compensation factor and geometric compensation factor), the system captures both sources of thermal error that would otherwise be lost
Solution Approach 2:
The patent introduces temperature as an intermediary parameter that mediates between the physical thermal effects and the measurement calculations. By measuring temperature and using it to calculate compensation factors for both stiffness and geometry, the system recovers information about geometric changes that would otherwise be lost, enabling more accurate measurements across temperature ranges
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 solution enhances the accuracy of mass flow and density measurements by accounting for thermal expansion and contraction, providing improved precision over the entire operating temperature range of the flow meter, reducing errors associated with geometric changes.
Implementation Method 1
the flow meter is often operated at temperatures that are different than the reference temperature
Data Source
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AI summary
Meter electronics (20) for geometric thermal compensation in a flow meter (5) is provided according to the invention. The meter electronics (20) includes an interface (23) configured to receive sensor signals and a temperature signal (T) of the flow meter (5). The meter electronics (20) further includes a processing system (24) coupled with the interface (23) and configured to receive the sensor signals and the temperature signal (T) and compute a geometric thermal compensation factor (TFe) for one or more flow conduits (130, 130') of the flow meter (5) using the temperature signal (T). The geometric thermal compensation factor (TFe) is used to process the first and second sensor signals.