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How to clean the electromagnetic flowmeter electrode after scaling

The intelligent electromagnetic flowmeter is the most common type of instrument used to measure flow in industrial production, because it has many excellent use characteristics and is favored by users. In the process of use, the electrodes often adhere to the dirt due to the influence of the measuring medium, and the amount of measurement is deviated. Therefore, the user needs to master the relevant methods of the electrodes of the electromagnetic flowmeter, and mastering this knowledge is to improve our maintenance efficiency. Extending the service life of our measuring instruments will be of great benefit.

We know that if the medium measured by the electromagnetic flowmeter is in a relatively dirty state for a long time, it will cause fouling on the electrode after the electromagnetic flowmeter is used for a period of time. If there is a difference between the conductivity of the fouling substance and the conductivity of the measured medium, measurement errors will occur. Moreover, the adhesion of sludge and oil to the electrodes will also cause the output of the instrument to oscillate and drift. Therefore, regular maintenance and cleaning of the electrodes of the intelligent electromagnetic flowmeter is a work and mastery skill that we must perform in the process of using the flowmeter.

Electromagnetic flowmeter electrode cleaning methods usually have the following
1. Mechanical Removal Method The mechanical removal method is to achieve electrode removal by installing a special mechanical structure on the electrode. There are currently two forms:

One is to use a mechanical scraper. A scraper with a thin shaft is made of stainless steel, the scraper is taken out through the hollow electrode, and a mechanical seal is used between the thin shaft and the hollow electrode to prevent the outflow of the medium, thus forming a mechanical scraper. When the thin shaft is rotated from the outside, the blade is rotated against the plane of the electrode end to scrape off the dirt. This type of scraper can be manually or automatically driven by a motor driven fine shaft. The domestic electromagnetic flowmeter Xi'an Yunyi's scraper-type electromagnetic flowmeter has such performance, and the performance is stable and easy to operate. <br />
The other is to install a wire brush for removing dirt in the tubular electrode, and the shaft is wrapped in a sealed "O" ring to prevent fluid leakage. This kind of cleaning device requires someone to pull the wire brush to clean the electrode, which is not very convenient to operate. It is not convenient for the blade type electromagnetic flowmeter of Xi'an Yunyi.

Second, the electrochemical method
The metal electrode of the intelligent electromagnetic flowmeter has an electrochemical phenomenon in the electrolyte fluid. According to the principle of electrochemistry, there is an interface electric field between the electrode and the fluid, and the interface between the electrode and the fluid is caused by the electric double layer existing between the electrode/fluid phase. The study of the electric field between the electrode and the fluid reveals that the molecules, atoms or ions of the substance have an enrichment or a poor adsorption at the interface, and it is found that most of the inorganic anions are surface active substances, which have a typical ion adsorption law, while the surface of the inorganic cation Very little activity. Therefore, the electrochemical cleaning electrode only considers the case of anion adsorption. The adsorption of anions is closely related to the electrode potential. The adsorption mainly occurs in the potential range which is more positive than the zero charge potential, that is, the surface of the electrode with a different charge. On the surface of the electrode with the same charge, when the residual charge density is slightly larger, the electrostatic repulsion is greater than the adsorption force, and the anion is quickly desorbed, which is the principle of electrochemical cleaning.

Third, the electric breakdown method This method uses AC high voltage electricity to periodically add between the electrode and the medium, generally adding 30~100V. Since the electrodes are attached, the surface contact resistance becomes large, and the applied voltage is almost concentrated on the attached matter, and the high voltage will break down the attached matter and then be washed away by the fluid. For the general safety, the electric breakdown method must be used to clean the AC high voltage directly on the sensor signal output terminal when the electromagnetic flowmeter interrupts the measurement, the signal line between the sensor and the converter is disconnected, and the power is off.

Fourth, ultrasonic cleaning method

The ultrasonic cleaning method uses the principle of ultrasonic high-frequency vibration to apply the ultrasonic voltage of 45~65 kHz generated by the ultrasonic generator to the electrode, so that the energy of the ultrasonic wave is concentrated on the contact surface between the electrode and the medium, thereby utilizing the ability of the ultrasonic wave to hit the dirt. Broken to achieve the purpose of cleaning.

Through the above introduction, I believe that everyone has a better understanding and understanding of the product, electromagnetic flow meter electrode cleaning method for inorganic pollution, the electrode can be immersed in 0.1mol / L diluted hydrochloric acid for 30 minutes, washed with pure water, and then immersed in 3.5MOL / L It is used after soaking for 6 hours in potassium chloride solution. 4~5s of hydrogen fluoride solution is immersed for 3~5s, taken out and rinsed with distilled water, then immersed in 0.1mol/L hydrochloric acid solution for several hours, rinsed with distilled water, calibrated, contaminated with organic oil and oil film, detergent can be cleaned with platinum or gold The surface was washed with pure water and then immersed in a 3.5 MOL/L potassium chloride solution for 6 hours. Platinum surface contamination seriously forms an oxide film. Platinum or gold surface can be polished with toothpaste, then washed with pure water, and then immersed in 3.5MOL/L potassium chloride solution for 6 hours. The length of the instrument's service life requires us to carry out daily maintenance, in order to ensure the correct measurement data.

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