How does a Micro Motion flow meter work?

Answer 1

You may not know it, but Emerson Automation Solutions’ Micro Motion flow meter is quite an impressive little device. This brand putted the first Coriolis flow meter on the market. Now, you can find many vendors selling similar flow meters, but Emerson did it first.

As the name denotes, the Micro Motion flow meter uses the Coriolis effect to measure. Coriolis flow meters provide some of the most accurate measurement on the market. They can measure flow and density, and you can find patented technologies on some devices that measure viscosity as well. We have a definitive guide to Coriolis Micro Flow meters here, if you want to check out our in-depth discussion about this type of flow meter.

The Coriolis Effect – The Micro Motion flow meter’s working principle

The Micro Motion flow meter’s measuring tube comes in a variety of shapes, and vendors have sales pitches for each of them. So you’ll have to decide for yourself which suits your purposes best. The most common is the omega or “U” sensor.

Whatever the shape, the tube has a drive coil to vibrate the tube at a specific frequency. And at the inlet and outlet ends of the tube, you find pick offs measuring this frequency.

If there’s no flow, then both pick offs of the Micro Motion flow meter vibrate at the same frequency, creating identical waveforms. When you have flow, it creates the Coriolis effect, a small twist that phase-shifts the waveforms from the pick offs. Thus, by measuring the amount of shift, you can calculate the mass flow rate.

And as for density, you’ll use the natural change of frequency that occurs in a change of fluid density. High density makes the frequency decrease, and low makes it increase. The Micro Motion flow meter uses these changes to find the density of the product with great accuracy.