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Electromagnetic flowmeters have many advantages, but improper selection, installation, or use can lead to increased errors, unstable readings, and even damage to the instrument. Next, we will introduce several reasons for errors in flowmeters: (1) The liquid contains solid phases; if the liquid has powdery, granular, or fibrous solids in it, this can lead to various problems ； ①slurry noise ； ②Electrode surface contamination ； ③A conductive deposition layer or an insulating deposition layer covers the electrode or liner ； ④The lining is worn or covered by deposits, reducing the flow cross-sectional area. (2) For liquids that are prone to crystallization, electromagnetic flowmeters should be used with caution. Some chemicals that tend to crystallize can be measured normally at normal temperatures; since the pipes used for transporting such fluids are well insulated, crystallization does not occur during operation. However, it is difficult to provide proper insulation for the measuring tube of an electromagnetic flowmeter, and as a result, as the fluid flows through this tube, cooling can cause a layer of solid to form on its inner wall. Since crystallization problems also arise when using flowmeters based on other principles, in the absence of any better alternatives, an “oring” electromagnetic flowmeter sensor with a very short measurement tube length can be employed, along with enhanced heat insulation for the pipeline upstream of the flowmeter. Regarding the pipeline connection method, ease of disassembling and assembling the flow sensor is taken into account, so that it can be easily removed for maintenance once crystallization occurs. (3) The liquid in the tube is not fully filled; this is due to insufficient back pressure or an improper installation position of the electromagnetic flowmeter sensor, as a result of which the measuring tube is not completely filled with liquid. The symptoms of this fault vary depending on the degree of non-filling and the flow conditions. If a small amount of gas flows in a stratified or wave-like manner within the pipe, the fault manifestation is an increase in error, that is, the flow measurement value does not match the actual value ； If the flow is bubble flow or plug flow, in addition to discrepancies between the measured values and the actual values, output fluctuations may occur due to the gas phase momentarily covering the electrode surface ； In the stratified flow in horizontal pipes, if the gas-phase portion of the flow cross-section increases, that is, if the degree to which the pipe is not filled with liquid increases, output fluctuations will occur. If the lack of liquid filling is severe enough such that the liquid level is below the electrodes, then an overfill condition in the output will arise. (4) Problems caused by improper selection of electrode and grounding ring materials: Electromagnetic flowmeters that experience failures due to a mismatch between the material and the medium being measured have electrodes and grounding rings as the components in contact with the medium; an inappropriate match leads to issues other than corrosion, primarily surface effects on the electrode surfaces. Surface effects should include: ① Chemical reactions (formation of a passive film on the surface, etc.) ； ②Electrochemistry and polarization phenomena (generation of potential) ； ③Catalytic action (formation of aerosols on the electrode surface, etc.). Grounding rings also have these effects, but to a lesser extent. (5) Problems caused by liquid conductivity exceeding the allowable range: Oscillations may also occur if the liquid conductivity is close to the lower limit value. Since the lower limit specified in the manufacturer’s instrument specifications represents the lowest value that can be measured under optimal operating conditions, and real-world conditions cannot always be ideal, it is common to encounter low-conductivity distilled water or deionized water whose conductivity is close to the lower limit specified in the electromagnetic flowmeter guidelines; as a result, fluctuations in the output occur during use. It is generally believed that the lower limit value of conductivity that can be measured stably is 1 to 2 orders of magnitude higher. For more information, please visit the company’s official website at http://www.yb1518.com/. Please keep this link when reproducing the content! http://www.yb1518.com/UploadFiles/2012717174126829.jpg