Variable Zero Algorithm for Coriolis Flowmeter Calibration
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Solution Overview
Problem
Existing Coriolis flowmeters face challenges in accurately measuring low flow rates due to non-linearities and errors associated with traditional calibration methods, such as push-button zero and two-rate zero calibrations, which fail to account for variable operating conditions like pressure and fluid density.
Innovation Solution
A method and apparatus that determine and apply preferred zero calibration algorithms based on fluid flow and density to improve mass flow rate calculations, allowing for both standard push-button zeroing and two-rate zero calibration, enabling accurate measurements under varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods (push-button zero or two-rate zero) are used, then the flowmeter can be calibrated, but measurement accuracy deteriorates at low flow rates due to non-linearities and errors
Solution Approach 1:
The patent implements dynamic zero offset adjustment by continuously monitoring operating conditions (pressure, temperature, fluid density) and automatically adjusting the zero offset value in real-time, rather than using a fixed static calibration value. This dynamic approach allows the flowmeter to adapt to changing operating conditions and maintain accuracy across varying flow rates.
Solution Approach 2:
The patent changes the parameters used for zero calibration by introducing a multi-parameter approach that considers pressure, temperature, and fluid density simultaneously. The system selects different calibration algorithms based on the specific combination of these parameters, enabling accurate compensation for non-linearities under various operating conditions.
2Ease of operation
If push-button zero calibration is used, then zero offset can be determined, but errors as high as 1% occur at low flow rates
Solution Approach 1:
The system performs self-calibration by automatically selecting and applying the appropriate zero calibration algorithm based on monitored operating conditions. The flowmeter autonomously determines whether to use push-button zero, two-rate zero, or other calibration methods without requiring manual intervention, thereby maintaining both ease of operation and measurement precision.
Solution Approach 2:
The patent incorporates feedback mechanisms where the system continuously monitors operating conditions and measurement results, then uses this information to select and adjust the appropriate calibration algorithm. This closed-loop feedback ensures that the most accurate calibration method is always applied for the current operating conditions.
3Device complexity
If a fixed zero offset is used from initial calibration, then the flowmeter operates simply, but accuracy deteriorates when operating conditions change
Solution Approach 1:
The patent implements a universal calibration system that can handle multiple calibration methods (push-button zero, two-rate zero, and other algorithms) within a single integrated framework. The system automatically selects the appropriate algorithm based on operating conditions, providing multi-functionality that maintains accuracy across diverse scenarios without requiring separate calibration systems.
Solution Approach 2:
The system transitions from static fixed zero offset to dynamic adaptive zero offset that automatically adjusts based on real-time monitoring of pressure, temperature, and fluid density. This dynamic adjustment mechanism maintains measurement precision under variable operating conditions while adding minimal complexity through automated algorithm selection.
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 the accuracy of mass flow rate measurements by adapting to different operating conditions, reducing errors and maintaining zero stability within specifications, even at low flow rates.
Implementation Method 1
An alternating current is passed to the drive coil for vibrating the conduit(s) at a desired flow tube amplitude and frequency
Implementation Method 2
the pickoffs can use the motion provided by the driver to induce a voltage
Implementation Method 3
As material begins to flow through the flowmeter, Coriolis forces cause each point along the conduit(s) to have a different phase
Data Source
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AI summary
A method for operating a flowmeter is provided. The method includes the steps of measuring a fluid flow in the flowmeter, determining at least one fluid characteristic, determining a preferred algorithm of a plurality of algorithms based upon the fluid flow and the at least one fluid characteristic, and applying the preferred algorithm to an operating routine.