Big bag filler for Belgian nanotube facility

Sambreville, Belgium - Carbon nanotubes company Nanocyl has selected Spiroflow to supply its Spirofil big-bag filler for a nanotube manufacturing facility in Sambreville. The Belgian company products range from single-walled nanotubes to double- and multi-walled versions, which are mainly manufactured via catalytic carbon vapour deposition. Nanocyl commercialises its products in the form of powders, pellets, liquid dispersions and films.

Traditionally, for most industrial applications, Spiroflow offers big-bag fillers with weighing platforms using weigh scales or load cells, typically achieving accuracies of +/-1kg. To meet the Nanocyl requirement of a weighing resolution accuracy of +/-20g, Spiroflow engineers adopted the ‘hang-weighing’ principle. This means that the highly sensitive load cells can be mounted high up in the structure of the filler.

The  big-bag filler weighs the contents of big bags and is claimed to be so accurate that it is also used to fill 2kg bags. Big-bag filling takes place under a nitrogen blanket. A folded, flat bag is rigged onto the big-bag filler and is then inflated with nitrogen. Displaced nitrogen is vented through a special filter unit into the atmosphere.

During filling, the base of the big-bag filler intermittently rises to vibrate the bag; it then lowers to allow weighing to continue. The bag is given a final vibration once the target weight has been achieved and recorded. This vibration is claimed to be critical to ensure that the contents of each bag are consolidated to render the bags in a stable and safe condition for handling and storage.

At the heart of the control box is a high-accuracy weighing instrument that receives signals from the high-sensitivity, high-accuracy load cells. These support the bag hanging frame, complete with its quick-release bag loop hooks. The weighing instrument is connected to a printer so that batch records can be made and kept.