Electromagnetic flow meter is the most favorite flow meter for measuring flow of dirty liquids such as waste water, sludge, slurry, sewage, etc, for its characteristics of not having mechanical parts that can be negatively influenced or damaged by the particles suspended in the dirty liquids.
Having said that, it can't be 100% immune to thickly scaled up deposits on the surface of the electrodes. Such scale built up, if it's of metallic nature, can decrease accuracy or even cause the meter to behave erratically.
To prevent this, the maintenance engineers at such sites shall perform preventive maintenance periodically to remove such scales built up on the surface of the electrode. First, the pipe must be fully emptied and the flow meter must be removed from the pipe. Then using a metal brush or flat scraper, the scale must be cleanly removed from the surface of the electrode. Then the flow meter shall be installed back on the pipe. As one can imagine, it involves many concerned parties to schedule it and sometimes, it may be necessary to bring heavy equipment if the flow meter is large size. Simply put, it's not a simple task.
The electrode scraping device was developed to make that job simple and easy. Its structure is shown below;
Because there are 2 electrodes sensing the flow velocity, 2 of these assemblies are attached both on the front and the back side of the flow sensor tube. The electrode scraper assembly has its turn handle exposed outside and lets you turn it thereby scraping the scales off the surface of the electrode inside the pipe.
So, there's no need for emptying the pipe, removing and reinstalling the flow meters.
The followings are the pictures of the actual assembly on the flow meter sensor..
By removing the cap, you can access the turn handle. Turn it several times to remove the scale built up on the electrode inside the pipe.
The electrode scraper on the inside of the pipe.
The handle with the cap on.
Please note that this is not a standard item and is available as an option, and there are limitations as below;
1. The lining must be rubber (which is usually selected for waste water and other dirty liquids).
2. The meter size must be at least 150mm.
To learn more about our MaxiFlo ME series electromagnetic flow meters, please visit our web.
