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Cleaning method of electrodes for electromagnetic flowmeter

Electromagnetic flowmeter If the medium of measurement of long-term relatively dirty, then the electromagnetic flowmeter in the work for a period of time, the electrode will produce scaling. When the conductivity of the scaling material and the conductivity of the medium are not at the same time, the measurement error will be brought. The adhesion of the sludge and oil to the electrode will also cause the instrument output to swing and drift. Therefore, in this case we need to regularly maintain and clean the electromagnetic flowmeter electrode. We introduce several electromagnetic flowmeter electrode cleaning methods for your reference.

The common methods of electrode cleaning are as follows:
1. Electrochemical method
The electrochemical phenomena of metal electrodes are found in electrolyte fluids. According to the electrochemical principle, there is an interfacial electric field between the electrode and the fluid, and the interface between the electrode and the fluid is caused by the electric double layer of the electrode/fluid interphase. The study on the electric field of electrode and fluid shows that the molecules, atoms or ions of the material have enrichment or poor adsorption in the interface, and that most inorganic anions are surface active substances, which have the typical ionic adsorption law, and the surface activity of inorganic cations is very small. Therefore, the electrochemical cleaning electrodes only consider the adsorption of anionic ions. The adsorption of anions is closely related to the electrode potential, and the adsorption mainly occurs in the potential range corrected by the zero charge potential, that is, the electrode surface with the different charge.   On the electrode surface of the same number charge, when the residual charge density is slightly larger, the electrostatic repulsion is greater than the adsorption force, and the anion is quickly off, which is the principle of electrochemical cleaning.
Mechanical Removal method
The mechanical removal method is to achieve electrode removal by installing special mechanical structures on the electrodes. There are currently two forms:
One is the use of mechanical scraping device. Made of stainless steel with a thin-axis scraper, through the hollow electrode to pull out the scraper, the fine shaft and hollow electrodes between the use of mechanical seals to prevent the media outflow, and then formed a mechanical scraping device. When rotating from the outside of the shaft, the scraper close to the electrical extreme plane rotation, scraping dirt. This kind of scraper can be manual, can also use the motor to drive the fine shaft to automatically scrape apart. China-made electromagnetic flowmeter in XI ' an cloud Tester's blade-type electromagnetic flowmeter has such performance, and stable performance, easy to operate.
The other is in the tubular electrodes, installed on the removal of dirt with the wire brush, the shaft wrapped in a sealed "O" ring to prevent leakage of the fluid. This cleaning device requires someone to often pull the wire brush to clean the electrodes, operation is not very convenient, no XI ' an cloud meter of the blade-type electromagnetic flowmeter convenient.
3. Ultrasonic Cleaning method
The ultrasonic generator generated by the 45~65khz ultrasonic voltage to the electrode, so that the energy of the ultrasound to focus on the electrode and the media contact surface, so that the ability to use ultrasound to crush dirt, to achieve the purpose of cleaning.
Electric shock Piercing method
This method uses alternating current high-voltage electricity to be added regularly between electrodes and media, and generally adds 30~100v. Because the electrode is attached, the surface contact resistance becomes larger, the voltage is almost concentrated on the attachment, the high voltage will penetrate the attachment and then be washed away by the fluid. Overall safety, the use of electric shock through the method must be in the flow meter interruption measurement, sensors and converters between the signal line disconnect, power failure, the AC high-voltage directly in the sensor signal output terminals for cleaning.