Electromagnetic Flow Meter Error Detection Circuit
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Solution Overview
Problem
Electromagnetic flow meters face precision issues when measuring fluids with high conductivity, permittivity, or when insulators or conductive objects interfere with the measurement, leading to inaccurate flow rate calculations.
Innovation Solution
An error detection circuit is introduced, comprising a differential noise measurement circuit to quantify magnetic flux differential noise and an index calculation circuit to assess errors in flow rate calculations, allowing for precision evaluation and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electromagnetic flow meter is calibrated using tap water, then the flow rate can be measured at precision similar to calibration before shipment for fluids with conductivity and properties similar to water, but the flow rate cannot be measured at good precision when the fluid has high conductivity, high permittivity, or when insulators/conductive objects interfere with the measurement
Solution Approach 1:
The patent performs preliminary calibration using tap water to establish a baseline measurement precision, then uses the error detection circuit to evaluate and correct deviations when measuring different fluid types. The system pre-establishes reference values during calibration that can be used to assess measurement quality under various fluid conditions.
Solution Approach 2:
The error detection circuit provides feedback by calculating an error index based on magnetic flux differential noise levels. This feedback mechanism allows the system to evaluate measurement precision in real-time and determine when calibration or correction is needed when measuring fluids with different properties from the calibration fluid.
2Loss of energy
If a rectangular waveform magnetic excitation system with non-magnetic excitation period is used, then power consumption is reduced and abnormalities such as emptiness of measurement tube can be determined, but the system cannot detect errors in flow rate measurements for fluids with different properties from calibration fluid
Solution Approach 1:
The error detection circuit acts as an intermediary that monitors the measurement process by detecting magnetic flux differential noise. This intermediary system evaluates the quality of measurements taken by the main rectangular waveform excitation system, allowing the primary system to operate efficiently while the intermediary ensures measurement accuracy.
Solution Approach 2:
The patent replaces complex mechanical calibration procedures with an electronic error detection and evaluation system. Instead of requiring physical recalibration for different fluid types, the system uses electronic detection of magnetic flux differential noise to assess and correct measurement precision.
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 solution enables accurate evaluation and correction of flow rate measurements in various fluid conditions, ensuring precise operation of electromagnetic flow meters even when measuring non-water fluids, thereby enhancing measurement reliability.
Implementation Method 1
a magnetic excitation coil (14) that generates a magnetic field orthogonal to a flow direction in the measurement tube
Implementation Method 2
measures the flow rate of the fluid flowing through the measurement tube based on an electromotive force generated between the detecting electrodes when the fluid flows through the magnetic field
Data Source
AI summary
An electromagnetic flow meter comprises a detector having a measurement tube, a magnetic excitation coil, and a pair of detecting electrodes; a magnetic excitation circuit; a flow rate calculation circuit that calculates the flow rate of a fluid flowing through the measurement tube; and an error detection circuit comprising a differential noise measurement circuit configured to measure a level of a magnetic flux differential noise based on an electromotive force generated between the pair of detecting electrodes disposed in the measurement tube and an index calculation circuit configured to calculate an index indicating an error in the flow rate calculated by the flow rate calculation circuit based on the level of the magnetic flux differential noise measured by the differential noise measurement circuit.