Burkert 8177 Mise En Service page 17

4 Mounting
Inflowing medium
Foam
Air turbulences
Standpipe measurement
16
Do not mount the instruments in or above the filling stream. Make sure
that you detect the product surface, not the inflowing product.
Fig. 13: Inflowing liquid
Through the action of filling, stirring and other processes in the vessel,
dense foams which considerably damp the emitted signals may form
on the product surface.
If foams are causing measurement errors, the sensor should be used
in a standpipe or, alternatively, the more suitable guided radar sensors
(TDR) should be used.
Guided radar is unaffected by foam generation and is particularly
suitable for such applications.
If there are strong air currents in the vessel, e.g. due to strong winds in
outdoor installations or air turbulence, e.g. by cyclone extraction you
should mount LEVEL TRANSMITTER 8177 in a standpipe or use a
different measuring principle, e.g. radar or guided radar (TDR).
By using a standpipe (surge or bypass tube), the influence of vessel
installations, foam generation and turbulence is excluded.
Standpipes must extend all the way down to the requested min. level,
as measurement is only possible within the tube.
LEVEL TRANSMITTER 8177 • 4 ... 20 mA/HART