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The measurement principle of intelligent electromagnetic flowmeters is based on Faraday’s law of electromagnetic induction. Its sensor mainly consists of a measuring tube, electrodes, excitation coils, an iron core, and a yoke housing. It is primarily used to measure the volumetric flow rate of conductive liquids and slurries in closed pipelines, including highly corrosive liquids such as acids, bases, and salts. This intelligent electromagnetic flowmeter is widely used in industries such as petroleum, chemicals, metallurgy, textiles, food, pharmaceuticals, and papermaking, as well as in fields like environmental protection, municipal management, and water conservancy construction. 1. The corrosion resistance of stainless steel electrodes is due to a very thin passivation layer on their surface, which brings the electrochemical reactions to an equilibrium state. Solid particles in the fluid strike the electrodes, damaging the passivation layer on their surface and disrupting the electrochemical equilibrium. When metal materials come into contact with fluid media, they have the ability to regenerate a surface passivation layer in order to maintain electrochemical equilibrium. During the establishment of electrochemical equilibrium, free ions in the metal and the fluid continuously undergo electrochemical reactions under the influence of the signal electric field. Solid particles strike the electrode, continuously destroying the protective passivation layer ； The electrochemical reaction repeatedly forms a passivation layer, resulting in significant fluctuations in the potential between the electrodes. These changing potentials cause fluid noise in the flow signal. This situation is what is commonly referred to as slurry noise in electromagnetic flowmeters. Theory and practice show that increasing the frequency of the electric field changes affecting electrochemical reaction signals can rapidly reduce the amplitude of fluid noise; this is why high-frequency excitation and dual-frequency excitation can be used to address slurry measurement issues. 2. Fluid friction lining and electrodes, which separate positive and negative ions generated in the fluid from the electrolyte fluid. The rougher the lining and electrode surfaces, the higher the concentration of free ions. Under the influence of the electric field generated by the electrode signal, some ions move toward the electrode, resulting in noise voltage; this type of noise is known as drift noise. Flow noise is more prominent during low conductivity measurements. Flow noise is related to the external electric field strength; at higher flow rates, the induced signal becomes larger, and so does the noise amplitude, resulting in unstable output. 3. Sudden changes in fluid conductivity and pH value can also generate flow noise; unstable measurements caused by the addition of chemicals upstream of an electromagnetic flowmeter are a typical example of this. The reason is that when different media are mixed unevenly, positive and negative ions tend to separate in the fluid; under the influence of the electric field generated by the electrode signals, some of these ions move toward the electrodes, resulting in flow noise voltage and thus instability in the output. 4. Due to the high flow velocity, the thickness of the laminar boundary layer near the lining and electrodes becomes very thin; the roughness of the lining and electrodes exceeds the thickness of this laminar boundary layer. When the fluid strikes this rough surface, the flow velocity diverges and changes abruptly. There are flow velocity components that are in the same direction (or opposite direction) as the central axis of the measurement tube; due to the effect of the signal weighting function, these components have a significant impact on the electrode signals, resulting in large positive errors. This is what constitutes flow velocity noise. For more information, please visit the company’s official website at http://www.yb1518.com/. Please retain this link when reproducing the content! http://www.yb1518.com/UploadFiles/2012717174126829.jpg