A new sophisticated de-aeration technique allows multinational engineered materials manufacturer J.M. Huber Corp. to be the first to package precipitated amorphous silica on a form-fill-seal machine into polyethylene bags instead of paper bags. The new compact package stacks better to make pallet loads more stable, cuts packaging costs and is recyclable.
Precipitated amorphous silica is used in a variety of consumer and industrial applications in the dental, food, feed, paints and coatings, paper and pharmaceutical markets. The low-density white powder is a good anti-caking and thickening agent but that same absorptive characteristic, as well as the amount of air contained in the particulate, makes it difficult to package.
Huber has installed two new form-fill-seal machines from Concetti North America Corp. that remove air from the product, making it possible to fill 10-kilogram bags (about 22 lbs) at speeds of 150 bags per hour (at a density of 7.49-lb/ft³). The new package costs less, is more secure and produces cleaner, well-presented bags.
Riccardo Concetti, sales and marketing manager at Concetti Group, gives us more details about the Huber installation.
Can you explain exactly how the system was designed to reduce trapped air? Please describe the complex densification screw feeders, including a double air evacuation process.
Concetti: The Huber install consists of two complete form-fill-seal machines each with a gross weigher and complex densification screw feeders, including a double air evacuation process to reduce the amount of air in each bag. Both packaging machines are transporting filled bags to a four-column robot palletizing machine.
Each FFS machine is equipped with a receiving hopper and a double-screw feeder system, fitted with filters and a vacuum arrangement to mechanically compact the product driven by the two densification screws. This first phase of the process partially reduces the volume of powder by removing some of the excess air. The product is fed to the filling mouth where a precise weight is dosed into the preformed bag.
The volume of the powder is further reduced with a second de-aeration system: sintered probes are inserted into the product in the bag and a vacuum applied, extracting more of the remaining excess air. The combination of the two systems allows a significant reduction of the powder volume coming from the process.
The single layer polyethylene bag is transferred to the sealing station. The air still in the bag is allowed to escape slowly though micro perforations built into the inner ply produced during the tubular film’s manufacture and known also as “venting system.”
How compact are the bags now? Can you cite a percentage reduction compared to the previous package?
Concetti: The scope of the project was to densify the packed silica by 35% to increased filled bag and net pallet weight, and reduce the dust during handling to improve the overall health and safety. Now they use polyethylene bags, which are stronger than the paper ones.
What size was the previous paper bag?
Concetti: The previous package was a paper valve bag. Huber’s target was to densify the packed silica by 35% to increased filled bag and net pallet weight. With this new package, which has a greater tensile strength, it’s easier to control the moisture and to minimize dust. Reducing trapped air inside the bags improves stacking for more stable pallets during shipping, unloading and warehousing. Reducing the amount of the dust has been lowered the production and transportation costs.
Huber had been using air valve packers to fill paper valve bags via the forced flow positive pressure technology. They wanted to abandon the paper valve sacks since the bags emit excessive dust during handling.