Vortex Flowmeter Selection- Fluid Velocity

[Oscillator]

Dear Friends,

I want to know if the velocity is one of the criteria when selecting the vortex flowmeter size.
Especially when the fluid is flammable gas or liquid.
In flowmeters, the flowmeter size could be less than the line size. So with a smaller flowmeter size, the fluid velocity increase.
With higher velocity, the possibility of building up static charge is high. This is a major concern while handling flammable fluids.
I would like to know of any guideline or thumb rule for such cases.


Thanks in advance

 

[danw2]

Velocity is critical factor for a vortex flow meter because vortex technology is inherently a velocity meter.

Go to this thread

And scroll way way down to the graphic of the velocity graph and the table of minimum flow rate values for various pipe sizes (for water).

At flow rates at or below the table’s minimum flow rate values, the flow meter outputs a zero flow rate value (4.0mA). At the low flow end, the flowmeter is in low flow cut-off mode because the formation of vortices is too infrequent to provide a useable flow rate value. Any brand vortex meter will have this inherent characteristic.

The manufacturer’s sizing program will indicate the useable flow rate range. Because it is a velocity meter, sizing usually shows better performance with line sizes smaller than nominal.

As an alternative, Thermal Dispersion technology tends to provide good meaurement at low flow rates so it is not as demanding for reduced pipe size meter runs or lengthy upstream/downstream steaight runs as vortex technology is.