Magnetic Flowmeter Field Spreader for Uniform Flux
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Solution Overview
Problem
Magnetic flowmeters face challenges in evenly distributing the magnetic field across the flow tube, leading to inconsistent measurement of fluid flow rates, as the magnetic field concentration is often highest near the coils and decreases towards the edges, affecting accuracy.
Innovation Solution
Incorporating a magnetic field spreader proximate the magnetic coil to distribute the magnetic field more evenly across the flow tube, combined with an exterior magnetic wrapper to form a complete magnetic circuit, ensuring consistent exposure of the process fluid to the magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a magnetic coil is used to generate the magnetic field, then the magnetic field strength increases with the length of the wire and concentration of loops, but the magnetic field distribution becomes uneven with highest concentration near the coils and decreasing towards the edges
Solution Approach 1:
A magnetic field spreader is introduced as an intermediary component between the magnetic coil and the process fluid. This spreader receives the concentrated magnetic field from the coil and redistributes it uniformly across the flow tube cross-section, solving the uneven distribution problem while maintaining field strength
Solution Approach 2:
The magnetic field spreader changes the spatial distribution parameters of the magnetic field, transforming it from a concentrated pattern near the coil to a uniform pattern across the flow tube. This parameter transformation resolves the contradiction between field strength and distribution uniformity
2Device complexity
If the magnetic field is concentrated near the coils, then the coil structure is compact, but the measurement accuracy decreases due to inconsistent exposure of process fluid to the magnetic field
Solution Approach 1:
The magnetic field spreader acts as a mediator that decouples the coil structure from the field distribution outcome. The coil can remain compact while the spreader ensures uniform field distribution across the flow tube, thereby maintaining both structural compactness and measurement precision
3Measurement precision
If a magnetic field spreader is added to distribute the magnetic field evenly, then the measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The magnetic field spreader is integrated with the flow tube assembly, merging the field distribution function into the existing structure. This combining approach improves measurement accuracy while minimizing the increase in overall device complexity
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 configuration ensures a more uniform magnetic field distribution across the flow tube, enhancing the accuracy and reliability of fluid flow rate measurements by maintaining the magnetic field strength throughout the flow tube cross-section.
Implementation Method 1
The electromagnetic coil applies an electromagnetic field to the flowing process fluid. Due to Faraday's Law of electromagnetic induction, a voltage or Electromotive Force (EMF) is generated between the pair of electrodes in the fluid.
Implementation Method 2
A magnetic field spreader is positioned proximate the magnetic coil and is arranged to spread the magnetic field emanating from the magnetic coil and direct the magnetic field into the flow tube.
Data Source
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AI summary
A magnetic flowmeter (102) for measuring flow rate of a process fluid includes: a magnetic coil (124A) arranged to apply a magnetic field to the process fluid. A pair of electrodes (124) electrically couple to the process fluid and are arranged to sense a voltage induced in the process fluid related to the applied magnetic field and the flow rate of the process fluid. A flow tube (108) of a non-conductive material is arranged to receive a flow of the process fluid therethrough. The flow tube (108) carries the magnetic coil (124A) and the pair of electrodes (124). Flow meter circuitry applies a current to the magnetic coil (124A) and receives the voltage sensed by the pair of electrodes (124). A magnetic field spreader (208A) is positioned proximate the magnetic coil (124A) and is arranged to spread the magnetic field emanating from the magnetic coil (124A) and direct the magnetic field into the flow tube (108). An exterior wrapper (206A) extends around the assembly and completes a magnetic circuit.