Two
parallel arranged pipes are rotated at their resonant
frequency by coils. Any mass flow passsing through the
tubes will generate coriolis forces which appear whenever
a mass moves radially in a rotating system. The forces
have opposed effects on the in- and outlet side, they
do slighty deform the pipes. The excursion of the pipes
is detected by sensors on the in- and outlet side. The
phase shift between the rotational frequencies of both
pipes is proportional to the mass flow rate.
The resonant frequency of both pipes changes in accordance
with the density of the medium. This effect is used
to determine the density.
The extent of deformation of the pipes depends on temperature.
Therefore the temperature is measured for compensation
purposes.
Using only one sensor primary values as mass flow, density
and temperature can be measured. Conversions allow for
calculation of further values like flow volume and concentration. |
