A Coriolis flow meter consists of two parallel tubes that are made to oscillate using a magnet. These oscillations are recorded by sensors fitted at the inlet and outlet of each tube. In a no-flow state, the oscillations are synchronised, i.e. in phase with each other, since there is no mass exerting any force on the tubes. On the other hand, any fluid or gas flowing through the tubes generates
Coriolis forces
, causing the tubes to twist in proportion to the mass flow rate of the medium. The magnitude of this twisting is measured by the sensors as a phase shift between the inlet and outlet of the tubes. And this phase shift is used to measure the mass flow rate of the medium. The tubes also oscillate at their own resonant frequency in proportion to the density of the medium through the tubes. This effect is used to derive the density of the medium. Knowing the mass flow rate and the density, it is then possible to calculate the volume flow rate of the medium.
A Coriolis flow meter is thus used to simultaneously measure the mass flow rate, density and temperature of any fluid or gas flowing through a pipe.