What makes modern and, above all, efficient production? Reliability, precision and flexibility are crucial. Where weighing technology is important, compromises are the wrong approach. What needs to be considered when weighing silos?
Innovative technologies not only enable optimum transparency with regard to storage, but also the strategic optimization of logistical structures and processes.
Precise silo weighing and reliable inventory control means effectiveness and efficiency close to the optimum. Keyword: just-in-time production.
With the right strategy, this can quickly become a competitive advantage.
The requirements and demands placed on measuring systems in warehouse logistics have increased.
However, the potential in terms of cost-effectiveness and sustainability is also much greater with the right equipment.
The limits of conventional measurement technology
As a rule, the fill level of silos, mixers and tanks is measured using volumetric measurement methods.
However, this technology is relatively susceptible to external influences.
For example, heavy dust and steam as well as chimney or bridge formation often lead to incorrect measurement results.
Systematic deviations are also not uncommon.
For example, a silo with a diameter of three meters and a cone of repose of 45 degrees results in a difference in volume of approximately 3.5 cubic meters.
Depending on the material value, the difference can quickly be in the four-digit range.
Furthermore, determining the fill level in tons via a volume measurement depends on a constant density.
If you make compromises here, you are not only wasting potential. But there is another way:
The possibilities of innovative weighing technology
There is virtually no alternative to gravimetric measurement methods for precise and reliable measurement results in the field of bulk materials and liquids.
Load cells can literally make the difference in production environments of this kind.
Nevertheless, the technology is still underestimated. This is primarily due to misconceptions.
The majority of plant manufacturers and operators still estimate the mechanical and electrical costs of container weighing systems to be higher than the actual benefits.
This is precisely where we would like to start:
Systematic silo weighing and inventory control
As a full-service provider in the field of weighing technology, we are almost naturally convinced of the effectiveness and efficiency of available weighing modules and sensors.
In the following, we would like to show you why; and at the same time make the effort and costs more transparent.
In our examples, we compare two different areas of application:
Outdoor silos with a capacity of 120 and 250 tons respectively serve as the basis.
While we illustrate the use of weigh modules for the smaller container, the second scenario highlights the upgrade with strain gauges.
Silo with weighing modules
Four Safemount weighing modules, each with a measuring range of 40 tons, were installed in the silo shown here.
load cell installed under silo, outside, weighing system
An integrated double shear bar in each of the steel modules ensures precise measurement results.
3D-model of load cell for silos, vessels, tanks with assembly
Additional safety measures in the form of links or restraints are not required due to the high-strength bolts.
Axial loads also pose no problem.
Any thermal expansion or minimal tilting of the head and foot plates are absorbed and compensated for without impairing the measuring accuracy.
Various modules in the product range also have corresponding TÜV approval.
The standard measurement tolerance is 0.05 percent, measured against the maximum filling quantity.
The Safemount modules are available for measuring ranges from 2 to 150 tons per module.
In an alternative version with a cylindrical measuring body, the weighing modules can also cope with structures weighing several thousand tons.
And here, too, the overall height is exceptionally low. With a nominal load of 300 tons, for example, the height is approximately 300 millimetres.
drawing of load cell for silos, vessels, tanks with assembly
Silo with weight sensors
It is not always possible to measure fill levels using a weighing module.
Weight sensors have therefore proven their worth when retrofitting existing production or storage silos.
The installation effort is minimal.
In addition, no mechanical changes to the supporting structure are required, as the strain gauges are simply attached to the supports or frames of the system.
This means that production can continue at any time during installation and is not affected by any conversion work.
At the heart of this maintenance-free and reliable solution are microcell sensors developed specifically for this application.
Based on the weight-dependent deformation of the temperature-compensated strain gauges, a linear-proportional voltage signal is generated, which is processed and read out as a measurement result.
weighing system with load cells, installed at several silos
The measurement of vertical support structures is carried out by load-related compression of the strain gauges.
For horizontal support structures or substructures with several silos, on the other hand, bending or shear are measured.
The system accuracy of the strain gauge sensors used also depends on the support structure. However, the production environment is also decisive.
While the measurement deviation on the inside is less than half a percent of the maximum fill weight, the deviation on the outside can be as much as one or two percent.
The difference is primarily due to thermal deformation caused by solar radiation.
Due to their high measuring accuracy, strain gauge sensors are also predestined for weight control when loading silo vehicles.
Control units and evaluation units
State-of-the-art evaluation units control both the processing of the signals and the display of the measurement results.
An "intelligent junction box" monitors the functionality and load distribution of each individual weighing module.
Any errors or deviations are not only displayed on the LCD, but also transmitted directly to the evaluation unit and stored.
functional schematic and components of complete silo weighing system
Data transmission via a so-called CAN bus also enables the connection of several control units.
This means that a network of silos or tanks can be set up with a manageable amount of effort and the dosing and loading workflow can be managed accordingly.
Costs
The total price for equipping the described solution with four Safemount weighing modules is between 4,000 and 5,000 euros per silo.
The system with four strain gauges costs around 3,000 euros plus installation.
Both price calculations include the junction box and the central display unit.
For new systems or if they can be retrofitted, it is advisable to equip them with load cells.
Weight sensors have proven themselves as a "retrofit solution" in a variety of different environments.
Conclusion
Where accuracy and operational reliability are required, load cells are the logical approach. Different solutions can be considered depending on the production process.
Regardless of whether with a weigh module or weight sensor, precise silo weighing and reliable inventory control ensure sustainable working and economic efficiency.
The investment can pay for itself within just a few months and therefore pay off on the bottom line.