6 Measuring point selection FLUXUS WW
UMFLUXUS_WWV1-1EN, 2018-02-28 27
6.3 Selection of the measurement arrangement taking into account the measuring range 
and the measuring conditions
Diagonal arrangement with 1 beam Reflection arrangement with 1 beam
• wider flow velocity and sound speed range compared to 
the reflection arrangement
• use in the presence of deposits on the inner pipe wall or 
with strongly attenuating gases or liquids (due to 1 sound 
path)
• smaller flow velocity and sound speed range compared 
to the diagonal arrangement
• transverse flow effects are compensated for because the 
beam crosses the pipe in 2 directions
• higher accuracy of measurement because the accuracy 
increases with the number of sound paths
Diagonal arrangement with 2 beams Reflection arrangement with 2 beams and 2 planes
• same characteristics as reflection arrangement with 2 
beams
• additional characteristic:
influences of the flow profile are compensated due to 
measurement takes place in 2 planes
• same characteristics as diagonal arrangement with 2 
beams
• additional characteristic:
transverse flow effects are compensated due to mea-
surement is conducted with 2 beams