Verification of flow
We would like to stress the fact that all the Eletta Flow Monitors are calibrated
and adjusted individually on water in a specially purpose built calibrated flow
rig in our workshop. This means that we have calibrated/adjusted the Monitors
under reference conditions with enough straight runs before and after, always
the same liquid, temperature, flows and pressure. If you find our Monitors to
show another value compared to a reference meter on site, it can well be due
to the fact that the reference meter has been calibrated under other reference
conditions and that our Monitor have other conditions on site in the actual ap-
plication, than we used under the calibration prior to shipping.
The Monitor is not showing any or the wrong value:
Is the Monitor mounted correctly with respect to the flow direction? Please
check the arrow on the outside of the pipe section with the actual (true) flow
direction For GL- and FA-models, check the flow direction selector inside
the monitor. Make sure that it is corresponding to the true flow, see 3.4.
Is there any flow in the pipe? And is it enough to create the needed ∆ρ?
Do you have the right orifice plate for the application? Check the stamped
values on the orifice plate. (pipe section model number and flow)
If you are using compression couplings into the Monitor inlet, check that the
inside diameter is enough to avoid the “nozzle” effect described above in
section 2.3 and also check the table for the minimum correct inner diameter
in the same section.
Are there enough straight runs upstream and downstream the Monitor? (10
diameters upstream and 5 downstream.)
Do you have valves or bends in more than one plane within the above
straight runs? If so, move the Monitor further away to achieve enough
straight runs.
Under the above section 3.1 it is described how the Monitor creates the diffe-
rential pressure. Eletta Flow Monitors work with two different ∆ρ’s i.e. on the
V1 and S2 units the ∆ρ is always maximum 2000 mm H2O (196 mbar) and for
the V15 and S25 units, the ∆ρ is always maximum 5500 mm H2O (539 mbar).
This means that at maximum ∆ρ the flow is always 100% in any Flow Monitor
mounted on any pipe section.
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