Electromagnetic flow meter is the application of the principle of electromagnetic induction, according to the conductive fluid through the applied magnetic field when the electric potential generated to measure the flow of conductive fluids of an instrument, because it is high precision measurement, stable performance, long working time, so in various industries can see its figure.

Electromagnetic flowmeter in many occasions is used to measure the viscous, or sludge such media, it is easy to cover the best electromagnetic flow meter of the two measuring electrodes, the measurement will be a problem, so the electromagnetic flowmeter needs to be cleaned regularly.

I. Electrochemical method

Electrochemical phenomenon exists in the electrolyte fluid at the metal electrode. According to electrochemical principles, 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 existence of a double electric layer between the electrode/fluid phase.

The study of the electric field at the interface between the electrode and the fluid reveals that molecules, atoms or ions of the substance have an enriched or depleted adsorption phenomenon at the interface, and it is found that most of the inorganic anions are surface-active substances with typical ionic adsorption laws, whereas the inorganic cations have very little surface activity. Therefore electrochemical cleaning of the electrode was considered only for anion adsorption.

The adsorption of anions is closely related to the electrode potential, and the adsorption mainly occurs in the potential range which is more positive than the zero charge potential, i.e., the surface of the electrode with a different number charge. In the same number of charge electrode surface, when the remaining charge density is slightly larger, electrostatic repulsion is greater than the adsorption force, the anion is quickly desorbed, which is the principle of electrochemical cleaning.

II. Mechanical removal method

Mechanical removal method is to realize electrode removal by installing a special mechanical structure on the electrode.

Generally, a mechanical scraper is used. Made of stainless steel with a fine shaft scraping out, fine shaft and hollow electrode with mechanical sealing to prevent media outflow, so the composition of the mechanical scraper. When rotating the thin shaft from the outside, close to the electrode end of the plane rotation, scrape off the dirt. This kind of scraper can be manual, can also use the motor to drive the fine shaft automatically scraped.

Third, ultrasonic cleaning method

The ultrasonic generator will produce 45 ~ 65kHz ultrasonic voltage added to the electrode, so that the ultrasonic energy is concentrated in the electrode and the media contact surface, so as to use the ultrasonic ability to break the dirt, to achieve the purpose of cleaning.

Fourth, electrical breakdown method

This method uses AC high-voltage electricity regularly added to the electrode and the media, generally add 30 ~ 100 V. As the electrode is attached, its surface contact resistance becomes larger, the added voltage is almost concentrated in the attachment, the high voltage will be attached to the breakdown, and then washed away by the fluid.

From the safety point of view, the use of electric breakdown method must be in the flow meter interruption measurement, sensor and converter signal line disconnect, power outage will be AC high-voltage power directly in the sensor signal output terminals for cleaning. Into an asymmetrical common mode voltage. Asymmetrical common mode voltage becomes a differential mode signal, resulting in zero offset.

Regular cleaning of the electrode will extend the service life of the electromagnetic flow meter factory. It is important to know that once the electromagnetic flowmeter failure, the cost of repair will be higher, only in the usual use can do regular maintenance, in order to reduce unnecessary losses, so that the value of the product to expand.