As an indispensable product in industrial production, instrumentation has been widely used in daily life. However, as a precision instrument, the flowmeter has many places for attention in daily use and daily maintenance. The electromagnetic flowmeter is an intelligent instrument, and its maintenance is especially important.

Electromagnetic flowmeter If the measured medium is relatively dirty for a long time, the electromagnetic flowmeter will produce dirt on the electrode after working for a period of time. When the conductivity of the fouling substance is different from the conductivity of the measured medium, measurement errors are caused. The adhesion of sludge and oil to the electrode will also cause the instrument output to oscillate and drift. Therefore, in this case we need to regularly maintain and clean the electromagnetic flowmeter electrodes. The following describes the cleaning methods for several electromagnetic flowmeter electrodes:

1.Mechanical removal method

There are currently two forms. (The mechanical cleaning method achieves electrode removal by installing a special mechanical structure on the electrodes).

One is to use a mechanical scraper to make a blade with a thin shaft made of stainless steel, and the blade is taken out through the hollow electrode. When the thin shaft is rotated from the outside, the blade rotates 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 other one 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.

2. Electrochemical method

Metal electrodes have an electrochemical phenomenon in the electrolyte fluid. According to the electrochemical principle, 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.

3. Ultrasonic cleaning method

The ultrasonic voltage of 45~65 kHz generated by the ultrasonic generator is applied 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 crush the dirt to achieve the purpose of cleaning.

4. Electrical breakdown

This method is periodically applied between the electrode and the medium using AC high voltage, usually 30~100V. Since the electrode is 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. From the safety point of view, the electric breakdown method must be used to clean the AC high voltage directly on the sensor signal output terminal when the flowmeter interrupts the measurement, the signal line between the sensor and the converter is disconnected, and the power is off.

Regular cleaning of the electrode will extend life of the electromagnetic flowmeter. It should be known that in the event of a malfunction of the electromagnetic flowmeter, the cost of repair will be relatively high. Only regular maintenance can be achieved during normal use, so that unnecessary losses can be reduced and the value of the product can be expanded.