SMC’s ALCM-UT uses two tubes formed into a U-shaped geometry in a parallel arrangement
which are vibrated at their resonant frequency by coils. Any mass flow passing through the tubes
will generate coriolis forces, which appear whenever a mass moves radially in a rotating system.
The forces have opposite effects on the inlet and outlet side, deforming each pipe by a minor
amount. The excursion of the pipes is detected by the inlet and outlet-side sensors. The phase
shift between the rotational frequencies of both pipes is directly proportional to the mass flow rate
and the resonant frequency of both pipes changes in accordance with the density of the fluid
media. This effect allows for measurement of the density. Using only one sensor, both density and
temperature measurements may be performed as the extent of deformation of the pipes is
temperature-dependent. Therefore, the temperature is measured for compensation purposes.
Using only one primary sensor, values including mass flow, density, and temperature may be
measured. The ALCM's microprocessor-based circuitry allows for conversions such as volumetric
flow and % concentration to be calculated.