Why do certain products have to be deaerated?
Some products contain a lot of air when they arrive from the silo or production process. They practically feel like water. If you simply package these products without removing the air, the bags will be practically impossible to stack. If you lay the bag flat, the air moves to the top of the product in the bag with a sort of balloon effect at the top. These types of bags obviously result in an unstable stack when stacked on a pallet.

And stacking is not the only problem. Air in the bag also has consequences for the shelf life of various products, as well as air- and moisture-sealing and storage. So deaeration is the answer, but how?

Packaging in standard PE foil or labyrinth bags
There are different ways of deaerating a product. You can use bags with perforation or subsequently make holes in the bags so the air can escape. This works excellently for sand, gravel, synthetic granules and materials that are not sensitive to moisture. However, with many powdery products you do not want any (micro)perforation or holes in the bag. They are hygroscopic, meaning they draw moisture from the air with the formation of lumps. Dust can also pass through the holes. These are scenarios you can better avoid.

We fully understand these sensitivities in the market, and that’s why we have been carrying out far-reaching research almost since our launch 30 years ago, initially in the powdered milk industry. Since 2000 we have also been using these techniques for other powders. After a great deal of testing and development, we came up with two effective solutions: vacuum packaging in standard PE foil or packaging in labyrinth bags.

Arolab and Arovac
We have also developed suitable machines for both systems:

• Arolab – for production in labyrinth bags: here the product is already deaerated to the extent possible when put in the bag. The bag is sealed and the remaining air further escapes during transport to the palletiser and particularly on the pallet itself.
• Arovac – for production in bags in standard PE foil: this process takes place in two stages. Firstly, probes are used when the bag is suspended at the filler opening and the product is poured into the bag. This is to optimally the fill bag. Secondly, the vacuum chamber is put to work to remove sufficient remaining air from the product and the bag so it can be nicely stacked as soon as the bag comes out of the machine.

Experience teaches us that vacuum packaging offers the most advantages for products in the cement industry, construction and the powdered milk industry. Stable pallets are then guaranteed. During packaging you are also less dependent on differences in density of the product because the length of the bag is ultimately determined under the flattener. So, the perfect bag time after time!

Would you like to get to know our technology? Our professionals will be pleased to advise you, contact us today.