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Half
Full or Half Wrong? The
Cone-Volume
Oversight
A
brand new, cone-bottomed
silo is installed and
filled to capacity with
a dry, granular product.
The plant manager wants
to monitor the volume of
the product and has
chosen to install a
non-contact ultrasonic
sensor at the very
top.
Before
commissioning, the
engineer is asked to
write the code that will
convert the measured
distance to a percentage
of total volume. During
the initial tests, with
the silo at 100% and
then 0% capacity, the
sensor and code work
perfectly.
Later,
with the silo half-full
of product, the plant
manager calls the
engineer and says the
level measurement is
clearly wrong.
Why
is the plant manager
convinced the level is
wrong, and what's the
simple geometry
oversight the engineer
made in the initial
calibration?
See
Answer Here
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UWT
Continuous
Level Measurement
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Radar
technology provides
highly accurate and
reliable results for
measuring both liquids
and bulk solids, even in
challenging
environments.
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How
It Works
Radar
technology uses
electromagnetic waves to
measure distance, level,
or position. A radar
sensor sends out a
focused wave that
reflects off an object
as an echo, which the
sensor then analyzes.
Radar systems include
both free-radiating
sensors and guided wave
radar (GWR) sensors,
which use guided
microwave technology,
also known as time
domain reflectometry
(TDR).
Key
advantages of using
radar for level
measurement
-
Unaffected
by process
conditions: Unlike
ultrasonic sensors,
radar is not
influenced by
changes in
temperature,
pressure, dust, or
other vapors in the
vessel's atmosphere.
The speed of radar's
electromagnetic
waves remains
constant, while the
speed of sound used
by ultrasonic
devices can change
with temperature and
air
properties.
-
High
accuracy and
reliability: Radar
sensors are known
for their high
precision. This
reliability is
maintained even in
harsh or wet
environments and
where there is
electrostatic
interference.
-
Handles
surface turbulence
and
foam: Surface
turbulence and
foaming can cause
unreliable readings
for ultrasonic
sensors, as the
signal can be
scattered. Modern
radar technology,
especially 80 GHz
frequency-modulated
continuous wave
(FMCW) radar, is
significantly less
affected and can
provide accurate
measurements even in
agitated or foamy
liquids.
-
Non-contact
measurement: As
a non-contact
technology, the
sensor is mounted
away from the
substance being
measured. This
prevents issues with
wear, corrosion, and
contamination that
can affect other
sensor types.
-
Versatility: Radar
is suitable for a
wide variety of
applications and
media, including
liquids, solids,
pastes, and powders.
It can also measure
liquids with low
dielectric constants
that are difficult
for other
technologies to
handle.
-
Low
maintenance: Radar
sensors have no
moving parts and are
less susceptible to
issues from
contamination and
condensation than
ultrasonic sensors.
This leads to
minimal maintenance
requirements.
-
Measures
through
materials: Some
radar sensors can
measure levels
through the walls of
plastic tanks,
allowing for safer
and easier
installation for
corrosive or
hazardous
materials.
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Non-contact
radar:
NivoRadar®
series
This
technology
uses
free-radiating
radar
signals
that are
sent
through
the air
and
reflected
by the
surface
of the
medium
without
making
physical
contact.
NivoRadar®
sensors
are
highly
accurate
even in
harsh
environments
with
dust,
high
temperatures,
or
agitated
surfaces.
High-Frequency
Technology
Radar
sensors
with
high
frequencies,
such as
80 GHz
technology,
can be
designed
compactly,
feature
narrow
beam
angles
of up to
3°, and
offer
excellent
reflection
properties.
This
enables
them to
deliver
precise
and
reliable
measurement
results,
even in
complex
tank
geometries
or
confined
shafts
and
pipes.
Typical
Applications
They
are
ideal
for
liquids
and bulk
solids
in
silos,
tanks,
and open
containers,
especially
when
non-contact
measurement
is
preferred
due to
hygiene
or
process
requirements.
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Illustrative
example
- bulk
solids
measurement
with
pouring
cone:
The beam
angle
increases
significantly
as the
frequency
decreases
– the 80
GHz
technology
offers
the
highest
precision
with
just
3°
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Guided-wave
radar (GWR): NivoGuide®
series
These
sensors use Time
Domain Reflectometry
(TDR)
technology, which guides
the radar signal along a
probe (rod or cable)
that is in direct
contact with the
measured medium.
NivoGuide®
is well-suited for
demanding applications
involving foam, steam,
or interface layer
measurement.
Low-Frequency
Technology
Guided
radar sensors often
operate at very low
frequencies (e.g., 1
GHz), making them
particularly resistant
to dust, build-up, foam,
or steam. This makes
them ideal for
applications involving
moving surfaces or
interface
measurements.
Customizable
Probe Types
Various
options, such as rod
probes, cable probes, or
coated probes (e.g.,
PA), allow flexible
adaptation to specific
process
requirements.
Typical
Applications
They
are especially effective
in challenging process
conditions, such as
highly dusty
environments within
silos or tanks
containing aggressive
media.
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Interface
measurement of liquids
with different DK
values:
The
microwave pulse reflects
off the upper layer
(e.g.,
oil),
penetrates
it, and is reflected at
the lower layer (e.g.,
water)
back
to the sensor
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NivoGuide®
Series By UWT Level
Controls
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