Methods for cleaning the electromagnetic flowmeter
Author:vacorda Source:vacorda.com Date: 2018-08-24 15:41:31
Electromagnetic flowmeter is an instrument that uses the principle of electromagnetic induction to measure the flow of conductive fluid according to the electromotive force induced by the conductive fluid through the applied magnetic field. Because of its high measurement accuracy, stable performance and long working time, it can be seen in various industries.
Electromagnetic flowmeters are used in many applications to measure media with viscosity, or sludge, which easily covers the two measuring electrodes of the electromagnetic flowmeter. Measurements can cause problems, so the electromagnetic flowmeter needs to be cleaned regularly.
First, the electrochemical method.
Metal electrodes have 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.
Second, mechanical removal method.
The mechanical cleaning method achieves electrode removal by installing a special mechanical structure on the electrodes.
Mechanical scrapers are generally used. A scraper with a thin shaft is made of stainless steel, 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, it 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.
Third, 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.
Fourth, electric breakdown method.
This method is periodically applied between the electrode and the medium using AC high voltage, usually 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.
Regular cleaning of the electrode will extend the life of the electromagnetic flowmeter. It should be known that in the event of a malfunction of the electromagnetic flowmeter, the cost of maintenance will be relatively high. Only regular maintenance can be achieved during normal use, so as to reduce unnecessary losses and increase the value of the product.