Ultraflux UF 831, User Manual, Page: 23 / 109

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NT UF 831 CO GB (b) / March 2014
There are 5 main steps to commissioning a measuring point and these must be followed very carefully. We
would also like to remind you that Ultraflux can help with commissioning of your flow meters (for further
information on this service, please contact us).
4.1 Choosing the measurement location
We highly recommend that you follow the instructions given in our document "Flow measurement by transit
time difference".
As a reminder, the main precautions to be taken are as follows:
 Choose a measurement location providing straight lengths upstream and downstream of around 10
times the width of the channel or the river.
 Also choose a location where there is little aeration of the water. You should therefore avoid
locations immediately downstream of:
o
a waterfall or a weir,
o
a screw-type pump,
o
a highly aerated grit chamber/oil separator,
o
an aerobic decantation installation,
o
a permanent tunnel aeration device.
4.2 Installing the probes
Given the many attachments and supports that are possible for wet probes (for open channels and rivers),
we will not go into each of them in detail, but rather list the general principles and prerequisites for smooth
operation of the installation.
1. When positioning the probe supports:
o
Respect the "axis diameter" when installing the supports. This value is provided by Ultraflux
and is calculated based on the range of velocities expected at the measuring point.
o
Position the probe supports on each bank so that the ultrasonic chord(s) is (are) parallel to
the water level (each probe the same distance from the water level).
2. When fixing the probe support:
o
Make sure that the position of the probe can still be adjusted (directional probes only).
o
Make sure that the attachments points are secure.
3. When aligning the probes:
o
Align the probes as far as possible using a laser sight or a rifle scope (depending on the
distance and the meteorological conditions),
o
Once the work has been completed, make sure that the probe alignment mechanism is
locked in place.
Comment: Probe alignment can be checked when the electronics have been put in place. You can then
simply view the relative gain on each chord in your flow meter.