A global chemical corporation was looking for a tailor-made solution to take care of the fully automated bagging process for industrial carbon black. However, packaging is not an easy task. Dust formation can occur during filling and present a health hazard for employees inhaling the air. At the same time, this also means that a certain amount of the precious product is lost. Another problem when it comes to the packaging such a fine powder is that if too much air is trapped, the bags become too voluminous and unstable. If that happens, up to 70 % of air is packaged too during the bagging process. The result: bulky bags that cannot be stacked properly. Naturally, the customer wanted to avoid this. The chemical company was looking for the best solution to handle around 40 bags per hour and bagging station. A high degree of automation, availability and 24-hour operation were important.
The Velovac from Greif-Velox is a fully automatic, vacuum-valve bag filling and sealing station for dust-free packaging. The principle behind the complex technology can be explained in simple terms: an atmospheric vacuum is created in the vacuum chamber, through which the product is sucked into the bags. Any dust that escapes is vacuumed and directly added to the bagging process. A total of two bagging stations were set up at the chemical company and adapted to the special requirements there. Each has a valve bag placing machine for the empty bags, with a valve size of 90 mm. The first step is to place the bags in the vacuum chamber. The carbon black is then sucked into them once the chamber is completely closed. Additional suction devices have been integrated into the Velovac chamber by Greif-Velox during and after bag filling in order to remove the dust. This means that no product is lost and the bags leave the chamber clean.
In the next step, the six-axis Velopack robot removes the full bags from the vacuum chamber and transfers them to the closing position. The bag valves are sealed using a patented technology. Ultrasonic oscillations of 20 to 40 µm at a frequency of 20 to 35 kHz eliminate product residues from the seam area and thus guarantee a reliable seal. A sealing rate of over 99 % is achievable. Any product remaining in the valve is removed by the Valvocut, a patented valve cutter. Particularly if the product has strong colouring and/or dusting effects, the production site remains clean and product and packaging material are saved. Another special feature here is that the sealing tools stay cold, so that energy consumption is lower. The machine is thus permanently ready for operation.
After sealing, the bags are weighed. Rigid valve bags are up to 50 % narrower than conventional bags. The filled bags are transported on conveyor belts to the palletising area. Finally, the Velopack palletising robot stacks the bags precisely one on top of the other, creating a tidy overall impression. Up to 22 layers can be stacked in this way.
Reduced logistics costs
The filled pallets are taken away by a shuttle system in order to secure the load and fit a hood stretcher. A fully automatic empty-pallet feeding system, including a cover sheet feeder for the empty pallet, is also integrated directly in the bagging stations. This was one of the customer’s requirements along with an additional palletising station for test bags.
The chemical company now fills around
90 bags per hour. The conversion to this fully automatic, low-maintenance solution has resulted in major changes: today, the customer’s logistics costs are around 73 % lower and occupational safety has been greatly improved by completely eliminating dust pollution. Optimal production reliability is ensured owing to the automatic self-cleaning system. There is virtually no waste and the availability of the system is guaranteed.
Profiting from digitisation
The full-line product handling systems have individual components that communicate as cyber-physical systems. The Velovac vacuum packer, for example, is a fully sensorial monitored system that displays the system status transparently in the user’s network. It provides data transmission from running processes, including process and quality parameters as well as faults, fault identification, load factors and much more besides. Maximum performance can be achieved through networking and appropriate remote services. All customer-specific processes from ERP and MES systems can be mapped. Data can also be collected for quality assurance purposes. When setting up a new product type to be filled, or if an error occurs in the process such as a change in dosing times or filling weights, the process engineers can re-parameterise the filling system on the screen of their office workstation anywhere in the world.
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