Study on the Mechanism of Excitation Switching Process in Electromagnetic Flowmeter to Overcome Slurry Noise

Abstract

The electromagnetic flow meter (EMF) is one of the most suitable flowmeter for slurry measurement. It is an important research point of electromagnetic flowmeter to overcome slurry noise in slurry measurement. The main approach to overcome slurry noise is to modify the excitation method and to improve the signal processing method. The novelty of this paper is the first study on the mechanism of excitation switching process to overcome slurry noise. The vortex electric field generated during excitation switching is theoretically analyzed and simulated based on Maxwell's equations. In order to evaluate the effectiveness of the vortex electric field to overcome the slurry noise, an experiment based on the step excitation signal is proposed. The results of the slurry noise power spectrum show that the increase of the excitation switching process can effectively suppress the slurry noise. The experimental results are consistent with the simulation results. On this basis, the stepwise excitation EMF was developed. Comparison results with conventional three-value excitation EMF show that increasing of excitation switch can effectively suppress slurry noise in real industrial measurement scenarios.