How are the difficulties posed by the drop in conductivity resolved?

　　Today Supmea, the manufacturer of electromagnetic flow meters, provides you with the following answers. Decrease in fluid conductivity will increase the output impedance of the electrode, and by the converter input impedance caused by the load effect and error, therefore, according to the principle described below, the electromagnetic flowmeter application of the fluid conductivity of the lower limit. The output impedance of the electrode determines the size of the input impedance required by the converter, while the electrode output impedance can be considered to be governed by the conductivity of the fluid and the size of the electrode.

　　In the theoretical analysis, the electrode is used as a point electrode, and the size can be ignored, but in fact, the electrode has a certain size, and when the circular plate electrode with the diameter of d is in contact with the semi-infinite spreading fluid with the conductivity of K, the spreading resistance is 1/2Kd, so if the diameter of the pipeline is D>>d, the output impedance of the electrode is the sum of the two spreading resistances, that is, it is equal to 1/Kd. Generally, the lower limit of the conductivity of the measured fluid is 5μS/㎝～10μS/㎝. The lower limit of the measured fluid conductivity is 5μS/㎝～10μS/㎝, so if the diameter of the electrode is 1㎝, the output impedance of the electrode is 1/Kd=100kΩ～200kΩ, and in order to limit the influence of the output impedance to less than 0.1%, the input impedance of the converter should be about 200MΩ.

　　Supmea produces electromagnetic flowmeter for many years, if you encounter any problems in the process of electromagnetic flowmeter selection, installation, use, maintenance, you can feel free to contact with Supmea staff, we answer for you.