Study of the Ability of an Electromagnetic Flowmeter Based on Step Excitation to Overcome Slurry Noise

Bin Li,Jie Chen,Xinghang Fan,Yue Yan

doi:10.1109/access.2020.3008419

Bin Li, Jie Chen + Show 2 more

Open Access

https://doi.org/10.1109/access.2020.3008419

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Abstract

An electromagnetic flowmeter (EMF) can be used to measure the speed of slurry fluid. In this paper, according to Maxwell’s equations and the dB/dt vortex electric field, a step excitation scheme is proposed. The original excitation process of the primary excitation current rise time is divided into a two-step excitation process. Without increasing the excitation current rise time, the equivalent excitation frequency is increased by increasing the primary dB/dt . This method can enhance the EMF’s ability to overcome slurry noise. The paper analyzes the design parameters of the step excitation scheme and designs the software and hardware. After that, the paper compares the step excitation scheme with the three-value rectangular wave excitation scheme based on wavelet transform signal processing. Experiments show that the step excitation EMF has a lower steady-state fluctuation rate when measuring mortar and has a stronger ability to overcome slurry noise. Additionally, the step excitation EMF and Yokogawa AXF 040G EMF are compared experimentally. Through flow calibration, clean water measurement, mortar measurement and dynamic response experiment, it is verified that the step excitation EMF has the ability to enhance the resistance to slurry noise at the same excitation frequency.

Highlights

Electromagnetic flowmeter (EMF) is widely used in modern industrial production
Under the guidance of this mechanism, this paper proposes a step excitation technology, which improves the excitation scheme, improves the equivalent excitation frequency without increasing the rise time of the excitation current, and improves the ability of an EMF to overcome slurry noise
The results show that the mortar measurement performance of the step excitation EMF during low frequency excitation is slightly weaker than that of the Yokogawa EMF

Summary

INTRODUCTION

Electromagnetic flowmeter (EMF) is widely used in modern industrial production. It is not easy for an EMF to become blocked because there are no movable parts and throttling parts in the pipe. Under the guidance of this mechanism, this paper proposes a step excitation technology, which improves the excitation scheme, improves the equivalent excitation frequency without increasing the rise time of the excitation current, and improves the ability of an EMF to overcome slurry noise. The step excitation method is proposed to give full play to the role of the vortex electric field E in cleaning and rectifying the interference charges on the electrode surface in the process of excitation switching to enhance the ability of an EMF to overcome slurry noise. To increase the magnetic field switching frequency without increasing the overall rise time of the excitation current, this paper proposes step excitation technology. 1) INFLUENCING FACTORS OF THE MINIMUM EXCITATION CURRENT a: FROM THE PERSPECTIVE OF SENSITIVITY The sensitivity of an EMF sensor is expressed as the value of the induced electromotive force generated per unit flow rate. From the perspective of easy implementation, the step excitation scheme currently uses two steps

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Findings

CONCLUSION