Magnetic-Inductive Flow Meter Signal Noise Compensation
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Solution Overview
Problem
Magneto-inductive flowmeters face challenges in accurately measuring flow types, especially with multi-phase liquids and viscous fluids, due to interference potentials from foreign matter and gas bubbles, which deteriorate measurement accuracy and make calibration difficult.
Innovation Solution
A method that involves generating a magnetic field with a time-varying intensity to induce a measuring voltage, separating noise and useful components of the measurement signal using digital processing, and determining the flow type by analyzing the noise spectrum, including median filtering and discrete Fourier transformation, to isolate and compensate for interference potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If magnetic-inductive flowmeters are used to measure multi-phase liquids and viscous fluids, then flow measurement capability is improved, but measurement accuracy deteriorates due to interference potentials from foreign matter and gas bubbles
Solution Approach 1:
The patent segments the measurement signal into useful component and noise component through spectral analysis. By separating the signal spectrum into different frequency ranges (useful spectrum below excitation frequency, noise spectrum above excitation frequency), the system can process each component independently, allowing accurate flow measurement even in the presence of interference potentials from multi-phase fluids and foreign matter.
Solution Approach 2:
The patent extracts the noise component from the total measurement signal by identifying and removing the spectral content above the excitation frequency. This extraction process isolates the interference potentials caused by gas bubbles and foreign matter, allowing them to be compensated separately from the useful flow measurement signal.
2Measurement precision
If excitation current is increased to improve signal strength, then measurement sensitivity is improved, but interference potentials from foreign matter increase, worsening measurement accuracy
Solution Approach 1:
The patent converts the harmful interference potentials into useful information by analyzing their spectral characteristics. The noise component, which contains interference from foreign matter and gas bubbles, is transformed into a diagnostic tool through spectral analysis. By examining the noise spectrum, the system can identify and compensate for interference patterns, turning what was previously a measurement obstacle into a source of additional measurement information.
Solution Approach 2:
The patent introduces spectral analysis as an intermediary processing step between signal acquisition and flow calculation. This intermediary process separates the useful signal from interference potentials through frequency-domain transformation, allowing the system to handle high excitation currents while maintaining accuracy by filtering out the resulting interference through spectral decomposition.
3Device complexity
If conventional signal processing is used to simplify the measurement process, then device complexity is reduced, but ability to detect and compensate interference potentials is worsened
Solution Approach 1:
The patent replaces complex hardware-based interference filtering with software-based spectral analysis. Instead of using additional physical components to separate signal from noise, the system uses digital signal processing techniques (Fast Fourier Transform) to achieve separation in the frequency domain. This substitution maintains measurement accuracy while avoiding the complexity of additional hardware systems.
Solution Approach 2:
The patent changes the processing domain from time-domain to frequency-domain analysis. By transforming the measurement signal through spectral analysis, the system changes the parameter representation from temporal waveforms to frequency spectra, making it easier to identify and separate interference potentials based on their characteristic frequency positions relative to the excitation frequency.
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 reliable detection and compensation of interference potentials, improving measurement accuracy even with asymmetric flow profiles and multi-phase fluids, enabling precise determination of flow types and triggering alarms when deviations occur.
Implementation Method 1
Generating a magnetic field that penetrates the medium in the measuring tube at least in sections with variable intensity, especially with clocking, in such a way that a measuring voltage is induced in the medium at least temporarily, especially cyclically
Data Source
Figure 1a
Figure 1b
Figure 2a~2c
AI summary
In the method according to the invention, a medium to be measured is allowed to flow through a measurement tube of the flow meter and a magnetic field penetrating the medium in the measurement tube with at least partially variable intensity over time is generated, such that a measurement voltage is induced in the medium at least intermittently, particularly cyclically. The measurement voltage induced in the medium is tapped at least intermittently by means of an electrode pair comprising a first and a second measurement electrode in order to generate at least one analog measurement signal corresponding to the measurement voltage, and a flow type of the medium present in the measurement tube, said type being determined by a momentary flow profile and/or a momentary composition of the flowing medium, is determined using a digital signal representing the at least one measurement signal. Assuming that the measurement signal has a usable component corresponding substantially to a momentary flow speed of the medium and a noise component influenced at least partially by current disturbances in the flowing medium, a noise spectrum of the measurement signal corresponding to the noise component and, using at least part of the noise spectrum, at least one state value at least qualitatively signaling the flow type present in the measurement tube are determined.