SiloWeigh - Applications and examples
Siloweigh and SiloWeigh.Net are being used on a wide variety of storage vessels, from small
bins and silos up to silos of over 4000 tons capacity and liquid tanks
of all sizes. It is also applicable to many structures, showing
real time stress and giving timely warnings.
H-beam silo legs
right is an example of installation of the now obsolete Silex
sensor on an H-beam leg, the most
common type in North America. This installation uses the
Through-Hole installation kit, which includes tools and a jig
for installation of up to 8 sensors.
sensors on any silo, check the available stress in the legs
using the Stress Calculator. This easy to use tool gives
you a go-nogo indication in a few minutes, based on theory plus
a lot of experience.
- download Excel file.
O-beam silo legs
at left shows installation of now obsolete Silex sensors on a silo with round legs. The
weld tabs installation kit is used on this type of installation;
the kit holds parts for up to 8 legs and a jig for positioning
the tabs while welding. The L-Strain sensor uses 3weld tabs but
the principle is identical.
The exact position of the sensors on the
legs is important for best results. The detailed manual
includes examples for most types of structure, plus rules for
other types that may be encountered. Scale-tron also
offers free engineering help and assistance with more difficult
right are skirted silos, where the wall of the silos runs right
down to the ground and supports the weight of the whole silo.
This application uses the through-hole kit again, with spherical
washers to allow for the curvature of the wall, and
installation is quite simple. Some of these silos use
additional reinforcement by beams bolted to the inside wall of
the silo. In cases like this, contact Scale-Tron`s
engineering team for advice on sensor positioning.
Aluminum and stainless steel skirts are no longer a problem because
the L-Strain sensor compensates for the difference in
coefficient of expansion. Accuracy may be reduced, however, and
you should contact us for the latest update from our extensive
If you can lift the vessel, the legs can be mounted on load
cells. The feed silos at left were converted to a highly
accurate vessel weighing system without lifting by
cutting the bottom of each leg in turn, refitting the foot and
bolting onto the load cell mount. This gives full load cell
accuracy; typically 0.1% of full scale. Useful when fine
accuracy is required or when dealing with awkward leg styles
that either do not allow gauges to be fitted or are too flexible
All SiloWeigh display systems are compatible with
load cells. We have supplied many load cell
systems where this exta accuracy is required.
These systems are not approved for use in trade,
however. If you need an approved system, we
can supply different indicators.
No cable run available?
No way you can run a cable? - No problem! we can use
a radio link to replace a long cable or even a run
of several miles between outlying silos and the base
station. We also have solar power kits when no
power is available at these outlying sites; this is
particularly useful with explosives silos that are
located in the backs of quarries and mines. A
choice of low power or higher power radio plus
high-gain antennas allow low-cost basic short
distance communication of several hundred feet up to
multiple location sites at several miles distance
with single base-station. The radio link
replaces the serial digital cable from silos to
SiloWeigh II indicator, or DAQ in the case of
SiloWeigh.Net, and radios can be networked to allow
multi-hop routing when distances are too great to
reach from the most distant location to base.
Analog 4-20 mA converter
Each DJB (Digital Junction Box), which normally
handles load cells, can be fitted with four
converters, making it compatible with all sensors
having 4-20 mA output. This opens a world of
applications to all the features of SiloWeigh.Net's
Internet database. Since each DJB has 4
inputs, the overall cost of putting your inventory
on-line is low, and level measurements can be
converted to volume during calibration, so you get a
direct readout in gallons or liters. See the
By fitting a pressure sensor into a T-adapter in the outlet
pipe, a measurement of the head of liquid allows this level to
be displayed. In addition, if the tank is symmetrical, as
shown here, the level can be converted to volume and displayed
in gallons, liters etc. Since the pressure measurement
corrects for specific gravity, the reading is always correct to
the temperature at which it was calibrated, regardless of volume
change with temperature.
liquid displays can be combined
with the weight displays in the same cabinet to show both;
for example, the displays can show both silo weights and
admixture tank volumes in a typical concrete plant.
Petrochemicals require special attention and intrinsic safety
barriers. Contact us for
information on how this can be handled.
When leg or skirt sensors cannot be used - for example, with joined
vessels or concrete silos, you can use radar or ultrasonic level sensors
and the level measurement can be converted to volume or weight.
The analog 4-20 mA converters above give Internet accessibility and all
the features of SiloWeigh.Net at low cost.
Temperature monitoring is important in many applications. One example is
in precast and block plants to record the temperature trend in the mixer
or during the nighttime curing cycle. Temperature probes can be
connected and scaled to read, for example, 0 to 100 degrees Celsius or
50 to 200 degrees F.
In concrete plants, moisture sensors have analog outputs and can be
displayed on the bar indicators. These can be calibrated to show 0 to
20% moisture in the sand bins, or record mix moistures for batches
running through the mixer.