Aalborg Vortex Insertion User Manual
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contact with the fluid. The piezo crystals are encapsulated in a stainless steel
module. These sensor assemblies can be replaced if the need ever arises.
1.4 Calibration
Factor
The frequency at which vortices are shed is a linear function of fluid velocity,
and therefore, a measure of flow. In the range covered by the particular flow
meter,vortex frequency is insensitive to specific gravity, viscosity, and temperature
of the fluid and depends only upon the width (d) in inches and shape of the
flow element, and the inside diameter (D) of the pipeline in inches.
The frequency is:
F = SV/d
where :
F = Karman vortex frequency
S = constant (Strouhal Number)
V = fluid velocity at the flow element
d = face width of the element
The frequency relationship is accurately linear and reproducible, eliminating the
need for “wet calibration.” (See Figure 2.)
FIGURE 2
2.
HANDLING AND STORAGE
2.1 Handling
Precautions
The vortex flow meter has been tested and configurated at the factory.
When the instrument is received, it should be inspected for damage due to
mishandling during shipment. If damage is evident, report it to the carrier
immediately and have them present when the case is opened. They are responsi-
ble for any damage during shipment. If you have any problems or questions, con-
sult the factory or your local representative.