Coriolis Mass Flowmeter Phase Error Compensation
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Solution Overview
Problem
Coriolis mass flowmeters face measurement errors due to inherent phase differences in measuring channels, which are not effectively compensated by existing channel switching methods, leading to reduced data output rates and transient issues.
Innovation Solution
The method employs multiple measuring channel pairs with different conversion factors and filtering techniques to calculate error-free oscillation signal phase differences, where one pair averages out phase errors, another pair accounts for errors with averaging, and a third pair with negligible phase difference provides data at varying rates, allowing for independent data rate adjustment and error correction without quality loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If channel switching is used to compensate for measuring channel phase difference, then measurement precision is improved, but productivity deteriorates due to lower output rate
Solution Approach 1:
The patent divides the measuring channel pair into multiple segments (first, second, and third measuring channel pairs) with different characteristics. Each segment processes signals differently - the first pair uses switching for error compensation, the second pair provides continuous signals, and the third pair offers high-rate data. This segmentation allows simultaneous achievement of measurement precision through error compensation and productivity through multiple data sources.
2Measurement precision
If channel switching is used to compensate for measuring channel phase difference, then measurement precision is improved, but device complexity increases due to switching mechanisms
Solution Approach 1:
The patent introduces intermediary processing elements - specifically, evaluation units that receive signals from multiple measuring channel pairs and compute compensated phase differences. These evaluation units act as mediators that combine the outputs of different channel pairs (including the switched first pair and the continuous second pair) to produce the final measurement, thereby managing the complexity of channel switching while maintaining precision.
3Measurement precision
If channel switching is used to compensate for measuring channel phase difference, then measurement precision is improved, but stability deteriorates due to transients and filter dependencies
Solution Approach 1:
The patent applies different processing qualities to different parts of the signal chain. The first measuring channel pair uses switching with specific filter settings optimized for error compensation, while the second measuring channel pair provides continuous signals with different filtering characteristics. This local differentiation of signal processing qualities allows the system to achieve precision through error compensation while maintaining stability through the continuous, transient-free signals from the second pair.
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 significantly reduces measurement errors and maintains high data output rates by accurately determining mass flow rates with minimal phase errors, effectively overcoming the limitations of prior art methods.
Implementation Method 1
the oscillation generator excites the measuring tube into an oscillation at an excitation frequency
Implementation Method 2
the first and the second oscillation sensors capture the oscillations of the measuring tube on the inlet side and on the outlet side
Implementation Method 3
Using the Coriolis effect, the mass flow rate of a fluid through the measuring tube is determined
Data Source
AI summary
A method for operating a Coriolis mass flowmeter includes: calculating error-free oscillation signal phase differences using a first measuring channel pair with a first measuring channel phase difference; calculating averaged error-containing oscillation signal phase differences using a second measuring channel pair with a second measuring channel phase difference; determining error-containing oscillation signal phase differences using a third measuring channel pair with negligible measuring channel phase difference; determining the second measuring channel phase difference by difference formation from the averaged error-containing oscillation signal phase differences of the second measuring channel pair and the error-free oscillation signal phase differences of the first measuring channel pair; obtaining error-free oscillation signal phase differences by subtracting the determined second measuring channel phase difference from the error-containing oscillation signal phase differences of the third measuring channel pair; and using the error-free oscillation signal phase differences for determining the mass flow rate.