Scale-Tron, automation, sensors and weighing systems

L-Strain, advanced bolt-on strain-gauge sensors give accurate measurement on silo legs or skirts with little change as the structure heats and cools.  A stress sensing section measures the compression due to weight and a compensating section corrects the errors due to thermal expansion in the structure.  These sensors can be successfully applied to stainless steel and aluminum structures as well as all types of carbon and mild steel.  Mounting is by bolts through holes drilled in the leg on its neutral axis, where the structure is not weakened by these holes.  One sensor is mounted on each leg and they are connected by cables and junction boxes to the DJB (digital junction box) which transmits the sensor signals for all vessels on a single digital cable to an indoor location up to 1 km (3000 ft) away.  Accuracy is typically better than 2% of full scale capacity but this depends on the structure to which it is applied.
On curved surfaces and round legs, flat surfaced tabs are welded in place.  These tabs have threaded holes into which the sensor's bolts are fitted. For uneven surfaces and skirted silos, a spherical washer mounting kit is available.

Stress calculator - download Excel file to ensure that the stress in your structure is adequate for good results.

Classic weldable gauges For special applications, can be applied when bolt-on sensors cannot be used because of lack of room or other physical limitations.  Accuracy can be slightly better than the L-Strain sensors, depending on the application.  These sensors require surface preperation and a special spot welding gun for their application.  Gauges are sealed with a special silicone covering and a plastic box is fitted over the assembly for mechanical protection and overall weatherproofing.  Contact us for more details.

Stress calculator - download Excel file.

Liquid level sensor allows SiloWeigh to be used on tanks.  The combination of a pressure sensor, shown at right, plus the bar-graph meter can show either the level in the tank or the volume in gallons, liters etc. if the tank is symmetrical in the vertical direction.  Accuracy is excellent.
Even horizontal cylindrical tanks can be calibrated to read in volumetric units if the bar-graph meter is specially programmed to linearize the tank's circular shape.
An alternative submersible sensor is also available.  With additional equipment these sensors can be used with petrochemicals and other combustible liquids.  Accuracy is dependent on vessel symmetry when measuring volume;  typically within 1% on most tanks.  The expansion of the liquid with temperature does not affect the reading.

For the ultimate in accuracy, load cells are fitted under the silo or vessel.  Shown here is a shear beam load cell assembly supporting the leg of an agricultural type silo.  Load cell mounts are available up to several hundred tons per leg.  The vessel has to be lifted in order to fit these load cell mounts.  Accuracies of better than 0.1% can easily be obtained.  Contact us for further information.