Electromagnetic vortex street flowmeter for measuring flow of gas-containing conductive liquid

Abstract

The invention relates to an electromagnetic vortex street flowmeter for measuring flow of a gas-containing conductive liquid, comprising a hardware system and a software system. The hardware system iscomposed of a signal conditioning and acquiring module and a digital signal processing and control module, wherein the signal conditioning and acquiring module uses a two-stage alternating-current amplifier circuit and a DC-offset circuit to effectively extract a weak near-sinusoidal signal related to flow velocity, so that the requirements of a subsequent processing circuit are met. The digitalsignal processing and control module uses a DSP (digital signal processor) as a core. The software system is composed of a master monitor program, an initializing module, a watchdog module, an algorithm module, a human-machine interface module and an interruption module. The flow signal frequency is calculated by using a signal processing method based on signal differential and FFT (fast Fourier transform) spectral analysis, spectral center-of-gravity correction and medium filtering are also performed, and stable frequency output to reflect changes in the flow velocity is obtained.

Description

technical field [0001] The invention relates to the field of flow measurement, and is an electromagnetic vortex flowmeter, in particular an electromagnetic vortex flowmeter based on differential and fast Fourier transform for measuring the flow of gas-containing conductive liquid. Background technique [0002] The electromagnetic vortex flowmeter is a flow meter based on the principle of Karman vortex street and electromagnetic induction. It has many characteristics such as simple and reliable structure, small pressure loss and long service life. The electromagnetic vortex flowmeter uses electromagnetic methods to detect the frequency of the vortex. Compared with the vortex flowmeter, its output signal is not affected by the interference of pipeline vibration and surrounding vibration sources, and the measurement reliability is high; compared with the electromagnetic flowmeter , low signal processing difficulty, no zero drift. For the flow of single-phase conductive liquid,...

AI Technical Summary

Problems solved by technology

Due to the interference of bubble noise, the signal is distorted. At this time, if the processing method of single-phase flow is still used, the correct flow signal frequency may not be obtained, resulting in large measurement errors.

However, domestic and foreign scholars have not conducted research on the subject of measuring gas-liquid two-phase flow with electromagnetic vortex flowmeters.

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