Electromagnetic Flowmeter Signal Processing for Noise Reduction
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Solution Overview
Problem
Existing electromagnetic flowmeters face challenges in accurately measuring fluid flow due to unwanted influences such as electrode misalignment, coil arrangement issues, wear, empty-tube-detecting voltage signals, and power-frequency interference, particularly for fluids with low electric conductivity, leading to distorted signal profiles and reduced signal-to-noise ratios.
Innovation Solution
The flow-calculating scheme employs a calculating unit that utilizes conformal mapping to rotate measured signals, samples them at specific intervals aligned with power frequency multiples, and defines signal groups to eliminate oblique reference voltage influences, thereby reducing noise interference and enhancing accuracy through dynamic zero-level calibration and weighted calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electromagnetic flowmeter measurement is used, then flow measurement is obtained, but measurement precision deteriorates due to unwanted influences such as electrode misalignment, coil arrangement issues, wear, empty-tube-detecting voltage signals, and power-frequency interference
Solution Approach 1:
The patent extracts and removes unwanted influence components from the measured signal through signal processing. The calculating unit identifies and eliminates components related to electrode misalignment, coil arrangement issues, wear, empty-tube-detecting voltage signals, and power-frequency interference, leaving only the pure flow-related signal components.
Solution Approach 2:
The patent changes the temporal parameters of signal sampling by defining specific sampling intervals that are multiples of the power frequency period. This parameter change allows the system to sample at optimal moments when unwanted influences are minimized or absent, thereby improving measurement accuracy.
2Measurement precision
If sampling is performed at arbitrary intervals, then signal processing is simplified, but measurement precision deteriorates due to oblique reference voltage influences and noise interference
Solution Approach 1:
The patent defines specific sampling intervals as multiples of the power frequency period, changing the temporal parameters of signal acquisition. This ensures that sampling occurs at optimal moments when reference voltage influences are minimized, thereby improving signal accuracy without requiring complex real-time adjustment mechanisms.
Solution Approach 2:
The patent employs periodic sampling at intervals synchronized with the power frequency. This periodic action aligns the sampling moments with the natural cycles of the electrical system, automatically minimizing the impact of periodic disturbances like power-frequency interference and oblique reference voltage influences.
3Measurement precision
If conventional signal processing is used, then processing speed is maintained, but measurement precision deteriorates for fluids with low electric conductivity due to dominant noise factors
Solution Approach 1:
The patent extracts and removes noise components that dominate signals from low-conductivity fluids. The calculating unit specifically identifies and eliminates empty-tube-detecting voltage signals and other interference components, thereby improving the signal-to-noise ratio without requiring physical modifications to the flowmeter.
Solution Approach 2:
The patent changes the sampling interval parameter to be a multiple of the power frequency period. This parameter change allows the system to capture signals at optimal moments when noise influence is minimized, thereby improving measurement precision for low-conductivity fluids while maintaining efficient processing through fixed interval sampling.
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 improves the accuracy of fluid flow measurement by minimizing the impact of unwanted influences, ensuring precise flow calculation even in the presence of noise and interference, and maintaining stability across varying conditions.
Implementation Method 1
After the two coils are charged, a magnetic flux is formed in the tube, so that when the fluid flows through the magnetic flux in the tube, the fluid induces electromotive forces between the two electrodes
Implementation Method 2
when the fluid flows through the magnetic flux in the tube, the fluid induces electromotive forces between the two electrodes
Data Source
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AI summary
A flow-calculating scheme using an electromagnetic flowmeter (30) includes that: A calculating unit (302) assigns a first-direction pulse signal (102) as a reference signal (104). The calculating unit (302) defines at least one second-direction pulse signal (103) before the reference signal (104) as a first signal group (107). The calculating unit (302) defines at least one second-direction pulse signal (103) after the reference signal (104) as a second signal group (108). The calculating unit (302) utilizes the reference signal (104) and a first feature value of the first signal group (107) to obtain a first difference value. The calculating unit (302) utilizes the reference signal (104) and a second feature value of the second signal group (108) to obtain a second difference value. The calculating unit (302) calculates the first difference value and the second difference value to obtain a result weighting value. The calculating unit (302) utilizes the result weighting value to obtain a flow measurement result of a fluid (204).