Flow measurement
Vortex flowmeters
Strengths
Limitations
Long term stability
Not for low flow rates
Low sensitivity to process vari-
ations
Straight pipe run needed
Moderate set-up costs
Some pressure drop
No moving parts
Pipe vibration/ noise issues
Minimal maintenance
Limited turn-down
Good accuracy
Table 8: Strengths and limitations of vortex flowmeters.
A
bout the authors
Andy Mangell graduated from the
University of Exeter with a B.Sc (Comb.
Hons) in 1984. Andy spent six years in
the oil industry throughout Africa and
the Middle East working on both explo-
ration rigs and production facilities. Having returned
to the UK in 1990, Andy continued his sales career
within instrumentation initially as an area sales
engineer but ultimately as National Sales Manager
for a product distributor. In 1999 Andy joined the
Bronkhorst 'family and in 2002 set up Bronkhorst UK
at their Headquarters in Newmarket.
Henning Springer was born in Johan-
nesburg and attended the German
School Johannesburg. After matriculat-
ing he studied Electrical Engineering at
the University of the Witwatersrand
and graduated in 1986. He joined Anglo American
and gained extensive engineering experience while
working in the mining industry, both in the gold and
coal sectors. After 10 years in this industry he joined
Mecosa as technical director in 1997 and took over
as managing director in 2001. Enquiries: Tel. 011 257
6100 or email
Vortex flowmeters measure the frequency of vortices created by an
obstacle placed in the fluid stream, which are proportional to the
flow velocity. Velocity multiplied by pipe area again gives volumetric
flow. The measuring signal is not subject to drift, so Vortex meters
do not need frequent recalibration, although they are best used
with swirl-free, medium-to-high speed flow rates, which generate
sufficient vortices.
Conclusion
Compatibility with existing meters, familiarity with a traditional tech-
nology and a low purchase price are not necessarily the most valid
specifying criteria for many applications. New technology flowmeters
are offering increased levels of accuracy, fewer maintenance issues,
impressive digital output capabilities and competitive lifecycle costs,
which surely make them worthy of serious consideration.
