Interface Level Measurement
Suitable measuring principales for your individual interface application

Multiparameter
The name of the innovation in interface measurement
is FMP55 Multiparameter. This instrument combines
the advantages of the capacitance and guided
radar measuring principles. Emulsion layers may
cause signal losses in interface detection in
guided radar measurements. Only Levelflex FMP55
Multiparameter can guarantee safe measured values
for both the interface and the overall level with
this unique, redundant measuring system.
Applications up to 200°C /40 bar.
Capacitance
Media with a small dielectric constant (dc) cause
very small changes of the capacitance value.
Media with a high dc produce large capacitance
changes. In many interface applications, the medium
with the smaller dc value is on top, e.g. in
hydrocarbon on water. The upper medium merely
provides a minimum contribution to the overall
capacitance value – the issued level thus only
refers to the water level (the interface).
Applications up to 200°C /100 bar.
Radiometry
The gamma source emits radiation which is attenuated
as it penetrates the container wall and the medium.
On the opposite side of the container, a detector
converts the radiation received into an electric
signal. Different interfaces absorb the radiation
differently. If the transmitter has been calibrated
to the media by went calibration once, a correlation
to the measurement of the interface result automatically,
unaffected by process temperature and pressure. DDDDDDDDDDDDDDDDDDDDDD
Guided Radar
As the pulese impact the medium surface, only part of
the sending pulse is reflected. The other part penetrates
the medium. As the signal enters the lower medium with a
higher dielectric constant (dc) it is reflected once more.
Talking the delayed Time-of-Flight of the pulse through
the upper medium into consideration the distance to the
interface is determined in addition.
Application up to 450°C/400 bar.
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