Ultraflux Uf 841, User Manual

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NT UF 841 CP GB (d) / June 2015
2) Multichord measurement
As multichord measurement copes better with irregularities in the speed profile, multichord measurements
can be used on straight lengths much smaller than those required for a monochord measurement.
For example, we have been able to test a measurement made using 4 parallel chords placed at 1.6 D from a
T followed by a butterfly valve. The error under these very unfavourable conditions was 2 %. Under the
same conditions, a monochord measurement would have generated an error of the order of 10 %.
Recommended locations
Vertical pipes with rising flow
Low points of horizontal pipes
Siphon mounting for pipes with a slight slope
Comment :
The values shown must
be multiplied by 2.5 for
gases.