Electromagnetic Flowmeter Magnetic Wrap Angle for Low-Flow Linearity
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Solution Overview
Problem
Conventional electromagnetic flowmeters suffer from poor measurement linearity and precision at low fluid velocities, leading to significant measurement errors and deviations when used in different flow conditions.
Innovation Solution
The electromagnetic flowmeter is redesigned with a magnetic conductive member having a wrap angle of 35 to 70 degrees and optimized magnetic field distribution, including chamfered or rounded edges and a profiled magnetic core, to enhance measurement linearity and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional electromagnetic flowmeter uses a standard magnetic field configuration, then the device structure is simple, but the measurement linearity is poor especially at low fluid velocities
Solution Approach 1:
The magnetic conductive member is designed with non-uniform distribution and specific wrap angles (35-70 degrees) to create localized magnetic field strengthening in regions where fluid velocity is lowest. This local optimization of magnetic field quality compensates for the velocity profile variation without requiring complete redesign of the entire magnetic field system.
Solution Approach 2:
The patent optimizes specific parameters including the wrap angle of the magnetic conductive member (35-70 degrees), the position and dimensions of exciting coils, and the magnetic permeability characteristics of the conductive member. These parameter adjustments transform the magnetic field distribution to improve measurement linearity while maintaining structural feasibility.
2Measurement precision
If the magnetic field strength is increased to improve measurement precision, then measurement linearity improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The magnetic conductive member is designed with curved surfaces that wrap around the measurement pipe at specific angles (35-70 degrees). This curved geometry naturally guides and concentrates magnetic flux in the required regions, achieving the desired magnetic field distribution through geometric form rather than complex material composition or assembly procedures.
3Measurement precision
If the wrap angle of the magnetic conductive member is optimized to 35-70 degrees, then measurement linearity improves, but the device complexity increases
Solution Approach 1:
The patent identifies and optimizes the wrap angle parameter to a specific range (35-70 degrees) that achieves optimal measurement linearity. By focusing on this single critical parameter rather than redesigning the entire magnetic system, the solution improves performance while limiting the increase in device complexity to a manageable geometric modification.
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 redesign improves measurement linearity and precision across varying fluid velocities, reducing measurement errors and ensuring consistent performance in both straight and bent pipe sections.
Implementation Method 1
one or more excitation coil is provided outside the measurement pipe and is configured to generate a magnetic field in a direction perpendicular to a direction in which the conductive fluid flows
Implementation Method 2
a magnetic conductive member arranged around the measurement pipe... the magnetic strength distribution within the measurement is optimized
Implementation Method 3
A pair of electrodes is arranged inside the measurement pipe and is configured to measure a voltage generated by the conductive fluid flowing within the magnetic field
Data Source
AI summary
An electromagnetic flowmeter includes a measurement pipe a pair; of exciting systems disposed on outer sides of the measurement pipe radially opposite to each other, each exciting system including an exciting coil generating a magnetic field according to a current supplied thereto and a magnetic conductive member arranged around the measurement pipe; a pair of electrodes disposed on inner wall surface of the measurement pipe radially opposite to each other and perpendicular to a magnetic field direction; wherein in a cross section of the measurement pipe, a wrap angle formed by the magnetic conductive member with respect to a center of the measurement pipe is in a range of 35 degrees to 70 degrees.