How to debug sewage electromagnetic flowmeter

Regarding fluid media

Liquid containing uniformly distributed small bubbles usually does not affect normal measurement. When the measured volumetric flow rate is the sum of the liquid and gas, the increase of bubbles will cause fluctuations in the output signal. If the bubbles are large enough to flow over the electrode and cover the entire electrode surface, the electrode signal circuit will be instantly disconnected, and the output signal will have greater fluctuations.

When two or more liquids are mixed in a pipeline, if there is a difference in conductivity (or electrode potential) between the two liquids, they will enter the flow sensor for flow measurement before being mixed evenly, and the output signal will also fluctuate.

Low frequency (50/16-50/6Hz) rectangular excitation electromagnetic flowmeter will generate slurry noise and output signal fluctuations when measuring liquids containing solids exceeding a certain content.

Poor selection of electrode material and tested medium can lead to chemical reactions such as passivation or oxidation, formation of insulating film on the electrode surface, as well as electrochemical and polarization phenomena, all of which can hinder normal measurement.

Pipeline system and installation, etc

Usually, faults are caused by incorrect installation of the electromagnetic flowmeter sensor. Common examples include installing the flow sensor at a high point in the pipeline where gas accumulation is likely to occur; The back pressure behind the flow sensor causes the liquid to be discharged directly into the atmosphere, resulting in a non full tube inside its measuring tube; Installed on a vertical pipeline from top to bottom, there may be reasons such as emptying.