Vortex Flow meters
Operating Principle
An everyday example of a vortex shedding phenomenon is a flag waving
in the breeze: the flag waves due to the vortices shed by air moving
across the flagpole. Within the flow meter, as flowing media moves
across the strut or “bluff bar”, vortices are also shed but on a smaller
scale. The meter transmits an ultrasonic beam through the vortex
pattern downstream of the strut. As vortices are shed, the carrier wave
of the ultrasonic signal is modified. This change in the carrier wave is
measurable and moves in proportion to the number of vortices shed.
Digital processing enables the vortices to be counted, and this value is
converted into a velocity. Software converts velocity into a volumetric
flow rate, in units of measure selected by the operator.
Racine vortex flow meters utilize the smallest strut in the industry, which
allows for high sensitivity; superior performance at very low flow rates;
large turndown ratios; and low pressure drop.
Through the use of an internal RTD and an external pressure sensor (optional),
the flow meter software will compensate for changes in pressure and
accurate mass flow measurement (gas meters).
