Magnetic Flowmeter Signal Processing for Solids-Induced Noise
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Solution Overview
Problem
Magnetic flowmeters experience significant noise distortion due to the impact of solids, leading to large measurement errors, especially in environments with high solid content, which conventional damping filters fail to effectively address.
Innovation Solution
A signal processing technique involving temporal mixing of raw flow data into multiple streams, followed by median absolute deviation (MAD) calculation and damping filters, to identify and reject noise spikes, thereby improving noise rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional damping filters are used to reduce noise, then the device complexity remains low, but the measurement precision deteriorates due to large measurement errors in high solid content environments
Solution Approach 1:
The patent divides the raw flow data into multiple separate streams through temporal mixing, where each stream processes a subset of the data. This segmentation allows individual streams to identify and reject noise spikes independently, then combines their results to achieve superior noise rejection (up to 18.5 times improvement) while maintaining measurement accuracy in high solid content environments.
2Measurement precision
If temporal mixing and MAD calculation are implemented, then the noise rejection improves significantly, but the device complexity increases due to additional processing steps
Solution Approach 1:
The patent segments the signal processing into distinct stages: temporal mixing of raw data into multiple streams, independent MAD calculation for each stream, noise spike identification, and result combination. This structured segmentation makes the complex processing manageable and enables parallel implementation, achieving up to 18.5 times noise rejection improvement while keeping the system organized.
Solution Approach 2:
The patent introduces median absolute deviation (MAD) calculation as an intermediary step between raw data acquisition and final flow measurement. The MAD serves as a statistical mediator that identifies noise spikes by comparing deviations from the median, enabling accurate noise rejection without requiring complex filtering algorithms.
3Measurement precision
If multiple signal processing streams are used to reduce noise, then the measurement accuracy improves, but the processing time increases
Solution Approach 1:
The patent segments the data processing into parallel streams that can be processed simultaneously rather than sequentially. Each stream independently processes a portion of the temporal mixed data, identifies noise spikes, and contributes to the final result. This parallel processing approach maintains high measurement accuracy while minimizing processing time loss.
Solution Approach 2:
The patent performs temporal mixing of raw data into multiple streams as a preliminary action before the actual noise identification and rejection process. This preliminary organization of data into manageable streams prepares the system for efficient parallel processing, reducing the overall processing time while maintaining accurate flow measurement.
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
The technique significantly reduces noise-related errors, achieving accurate flow measurements even in high solid content environments, with noise rejection improved by up to 18.5 times compared to conventional methods.
Implementation Method 1
The magnetic flowmeter energizes one or more coils by passing an excitation current through field windings which generate a magnetic field across an electrically isolated, conductive process fluid flow
Implementation Method 2
Magnetic flowmeters (or magmeters) measure flow by application of Faraday's Law, an electromagnetic effect. An electromotive force (EMF) is generated by the flowing process fluid crossing through the magnetic field
Data Source
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Figure 3A
AI summary
A magnetic flowmeter (102) includes at least one coil (122) configured to generate a magnetic field within a process fluid flow. A pair of electrodes (124) is configured to detect an electromotive force within the process fluid flow in response to the magnetic field. Measurement circuitry (132, 142) is operably coupled to the pair of electrodes (124) and is configured to provide an indication of the detected electromotive force. A processor (148) is coupled to the measurement circuitry (132, 142) and configured to receive the indication of the detected electromotive force. The processor (148) is configured to obtain a sequence of indications of detected electromotive force over a time interval and to generate a plurality of sets of emf samples by selecting non-contiguous indications of the detected electromotive force. Each of the plurality of sets of emf samples is processed by a signal processing engine to provide an emf sample output. The processor (148) is configured to combine emf sample outputs from each set of emf samples to generate a process fluid flow output. In another aspect, the processor (148) is configured to obtain the sequence of indications of detected electromotive force over a timer interval and generate a plurality of data streams from the sequence of indications of detected electromotive force. The processor (148) is further configured to perform signal processing on each stream to generate a plurality of stream outputs and to generate a process flow output based on a combination of the plurality of data stream outputs. In a further aspect, the processor (148) is configured to calculate median absolute deviation of each data stream to provide each data stream output.