Vortex meters for liquids, gas, steam
For applications where liquids, gases, steam or compressed air are to be measured, vortex meters based on the vortex principle, offer almost ideal prerequisites.
The physical principles of this procedure are based on the laws of the Karmàn vortex street:
The fluid flows around the bluff body in the pipe. The volume of the vortices remains constant. If you count the vortices, you also know the flow rate. The proportion between measured quality and output signal is linear for wide ranges. A sensor then translates the pressure pulses of the vortices into an electrical signal that may subsequently be processed in whatever way necessary.
- Vortex meters are easily assembled, reliable, accurate and suitable for almost any fluid.
- A sensor paddle projecting into the pipe is deflected by the vortex generated at the bluff body, thus changing the distance between the central electrode and the outer electrodes resulting in measurable capacitance drifts.
- Vortex meters are particularly often used to measure steam and as they only measure volume flow, steam flows are mostly balanced in mass units, they are often combined with a pressure and/or temperature sensor as well as the respective calculator unit.
Measuring principle comes of age: meters for liquids, gas, steam
By Dipl.-Hyd. O Seifert and EC Reiff, Endress+Hauser
Electricity+Control, December 2011 (pgs 20 – 21)