Mar. 22, 2021
We can use electromagnetic flow meters in tons of products in all kinds of segments. What we need are a minimum conductivity and volumetric flow. The article explains the installation, application, advantages, and disadvantages of this kind of flow meter.
We can use electromagnetic flow meters in tons of products in all kinds of segments. We just need a minimum conductivity and a need to know the volumetric flow.
As for electromagnetic flow meter price, it gives some of the best bang for your buck if you can fit one in the process. Vortex flow meters come second, and maybe between them, we can find ultrasonics and so on. Of course, some company portfolios may have devices which defy my statements, so a research here is important.
One point about electromagnetic flow meters: the liner that insulates the measuring tube. All electromagnetic flow meters have them. So with a product in contact all the time with that liner, we will need a material that will withstand your product.
If we use the wrong material, we can run into corrosion and abrasion, shortening the life of the measuring tube. Also, the process temperature is important here.
The electrodes have similar needs, as they too remain in constant contact with the fluid. Usually, we have two electrodes to measure the voltage, but we can have a ground electrode on the bottom of the measuring tube and empty pipe detection on the opposite side. These facts can eliminate electromagnetic flow meters as an option for your process, so during the sizing process, we need to check them out.
Even though electromagnetic flow meters start out as volumetric flow devices, they can measure mass flow, too. But how? The answer is simpler than we can imagine – just plug in the density of the product, and the electromagnetic flow meter will calculate the mass flow.
The electromagnetic flow meters can do it themselves, but usually, as a high-end feature, we may need a density meter for an assist. Second off, when we set the density value, we need to make sure this value remains stable, or the accuracy will suck. So, one should read the density from a density meter and calculate the mass flow based on the right information.
Mining companies often use an electromagnetic flow meter to measure slurry flow, with certain liners to reduce abrasion and a densimeter to send data for the electromagnetic flow meter to translate into an online mass flow measurement.
Meeting some installation requirements to keep good accuracy throughout the device’s life is important. Unlike Coriolis flow meters, we have a bunch of stuff to deal with for an electromagnetic flow meter.
The best way to install it is vertical, with the product going up, we have a filled or empty pipe. Half-filled pipes can cause measuring problems for the electromagnetic flow meter. Of course, we can install it horizontally, as long as you avoid half-filled pipes.
We might also need to modify the pipe. Some vendors claim that their meters will work on half-filled, so if we foresee that as an issue, then one must look into those claims.
Moreover, high temps in your process mean that we should install the device upside down. Again, some devices claim that they can skip this bit, but typically you need at least five times the meter size before the meter and two times after. This point can vary, so follow the recommendations in the manual from the vendor.
You can get more information about electromagnetic flowmeter by checking out a more recent article we wrote on how to install electromagnetic flowmeter.