Chemical Technology July 2016

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2 Chemical Technology • July 2016
Two of the process control industry’s
most recognisable names recently
announced plans to launch 80 GHz radar
instruments for liquid level measurement.
This development signals a brave new
world in level measurement, one where,
radar can go where it has never
gone before.
A matter of frequency
The benefits of 80 GHz radar in level
measurement applications
This heralds an exciting era in automation. With high-fre-
quency devices on the rise, now is a good time to exam-
ine why radar technology is coming into its own and the
benefits of using these new sensors in automated processes.
Advancements create availability
The availability of 80 GHz radar sensors is a function of cost
and innovation. Microwave development has advanced to
the point that it is comparatively affordable, and the de-
creased expense has led to increased use across multiple
industries. Just as computer hardware prices dipped low
enough to put a PC in every home, it is now possible to put
80 GHz radar in every plant. This was thought impossible
a mere 20 years ago.
Yet cost was not the only thing stopping plant operators
from using high-frequency radar before now. On their own,
high frequency sensors do not stand up to harsh process
conditions as well as their lower-frequency cousins, which are
adept at penetrating foamand performing through condensa-
tion and build-up. However, modern radar instruments are
engineered to overcome these obstacles with large dynamic
range and software algorithms that filter out interference.
These innovations have made the affordable technology
relevant to real applications.
Now that 80 GHz radar is available and practical for liquid
level measurement, users should get accustomed to sensors
with better focus, versatile size, and enhanced resolution.
Focus
This is the alpha benefit of 80 GHz radar; the one that makes
the others possible. In every process, signal focus is crucial
to accurate level measurement, and these new instruments
emit the most focused signals on the market.
Plant operators have struggled with unfocused radar
for decades. The wide beam angle of 26 GHz sensors (and
6 GHz sensors before them) made it difficult for radar
signals to miss agitators, heating coils and other vessel
internals. The reflections from these installations distorted
the echo curve and users were forced to make adjustments
to monitor the true liquid level. The new high-transmission
models have narrower beams that miss vessel installations.
It is as if they are not even there. That is welcome news in
chemical and food production, where obtrusive internals
are the norm and space is at a premium.
Superior focus makes for accuratemeasurement without
adjustment, but it also opens the door for two other major
benefits.
Size
Because their focus is amped up, 80 GHz sensors have