The Basics Of A Micro Motion Coriolis Meter

by | Mar 23, 2017 | Industrial Goods & Services

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There are many different ways to measure flow in a given system. Some measurement options measure differential pressure between two points in the system, while others use the Coriolis effect to measure flow.

The Micro Motion Coriolis meter is able to measure mass flow and density. Mass flow is different than volumetric flow. Mass flow is sometimes called bulk flow or mass transfer as it is designed to measure fluid movement when there are changes in pressure or temperature. The measurement of mass flow is also beneficial for many types of processing facilities where specific mixtures are produced by mass rather than on volume measurements.

The Coriolis Effect

It wasn’t until 1835 that the movement of gasses and liquids with respect to a frame of reference that was rotating was discovered. It was actually noted and described by a French mathematician named Gaspard Gustave de Coriolis, hence the name of the effect today.

How it Works

The Micro Motion Coriolis meter doesn’t rotate, rather it oscillates. As the liquid or gas enters the meter, it is split into two different tubes that are identical in size and parallel to each other in their path through the meter.

Along each of the tubes are specific points, called pickoffs. As the drive motor causes the tubes to resonate at their natural frequency, the connecting and parting of the magnetic pickoffs creates a sine wave through the tubes. When there is nothing in the tube, this is in harmony as both tubes are oscillating at the same level.

When the liquid enters the tube, the Coriolis effect of the liquid cause the tubes to twist, changing the pattern of the connections at the pickoffs. This difference causes the twist, which shifts the sine waves out of sync.

The difference between the sine waves is measured by the Micro Motion Coriolis meter, providing the mass flow rate of the liquid. When the frequency varies, it is possible to determine the density of the liquid as the wave frequency will change accordingly.

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