Agribusiness & Food

Concetti curtails corrosion chaos for Vlaeynatie

Fertilisers are essential to feed the planet’s growing population. Graham Rawlings, Concetti, explains the logistical challenges with bagging fertilisers and what can be done to package the material.

Vlaeynatie, a European logistics company based in Westdorpe, Holland, is a provider of maritime supply chain services including bulk handling and storage systems for fertiliser on behalf of major global producers.

Packaging fertiliser is not for faint heart. It’s a tough business, handling vast quantities of dusty, hygroscopic products at high speeds. Applications are ranked among the most arduous of all for both manufacturers and users of bag filling and palletising systems.

Products like urea, potash, ammonia sulphate, monoammonium phosphate (MAP), diammonium phosphate (DAP) and others are often manufactured as prills, 3-4mm diameter spheres, which help to reduce dust and improve the physical handling characteristics. Kept dry, the products are generally relatively easy to convey, feed or pack.

Hygroscopic fertilisers attract moisture which produce acids (sulphuric, phosphoric, nitric, or hydrochloric) or alkalis (ammonia for example), all of which are highly corrosive to steel and other metals.

Moisture in any quantity presents huge challenges to fertiliser operations due to this ever-present risk of corrosion. Without detailed attention to mitigate it, any exposed surfaces are soon little more than rust.

Not only did Vlaeynatie need to cope with the increased corrosion risk from port side locations, but also a wide range of products and bags and potential future products.

Paul Van den Broeck, director at Vlaeynatie, said bagging is the company’s speciality and main activity.

“Packaging serves as a quantity unit and protection of the product but is also a residual/waste product. As sustainability becomes more and more important, we need to limit this as much as possible,” he said.

What was once a simple jute bag evolved into woven polypropylene (PP) and increasingly, polyethylene (PE) bags which bring issues around waste and recycling. 

Vlaeynatie don’t just bag its own products, but provide a service to many global producers, both now and in the future. The company needs to be flexible, adaptable and constantly looking ahead for changes in the market.

Before selecting a supplier, Vlaeynatie had to consider many factors including the capacity needed, the type and size of bags foreseen, the palletiser best suited to the speed and duty. Should it use a robot or a layer machine? Should pallets be wrapped with spiral stretch film or a weatherproof hood?

“To make the right choice of bagging machine it is important to have a good knowledge of the products you want to bag, what is the density? granulate – powder? Free flowing? Are they weather sensitive? Disadvantages of humid weather conditions?” Van den Broeck said.

“Our main customers are producers, industrial players, of fertilisers who stock their products with us and entrust us with the entire aftercare of their product handling.”

Above all, Vlaeynatie understood that an automatic bagging and palletising line is not just about the bag filler, it is a chain of machines that must work together seamlessly. A chain is only as strong as the weakest link and output is always limited by the slowest unit.

After an initial request for bids was submitted to four possible suppliers, Concetti, an Italian manufacturer based in Perugia was selected because its proposal was, according to Van den Broeck, “constructive, creative, solution-oriented and tailored to our needs.”

“In addition, they gave us a total solution (from bagging machine to stretch hood including roller conveyors and communication) with good support from the start but also in the period afterwards. The undeniable advantage is that you only need to talk to one company, and they will relieve you of all your bagging problems,” he said.

Following the first installation in 2015, Vlaeynatie developed a close relationship with Concetti and further lines followed. Installations now include three automatic bag-filling and palletising systems, a single automatic bag filling machine plus two bulk-bag fillers, all handling various fertiliser products.

With the combination of Concetti lines now installed, Vlaeynatie can cope with a wide range of both powder and granular products using pre-made laminated woven PP bags and pre-made PE bags, either flat or gusseted. Closing can be done by heat sealing or sewing with or without fold over. In addition, the company can fill PE bags produced from tubular reels on two independent horizontal form-fill-seal lines. Bags of both 25kg and 50kg depending on the client’s needs can be handled at speeds up to 1700 bags per hour.

Finished pallets are over wrapped by two stretch hood machines.

Single or 4-loop bulk-bags of woven PP with inner PE liners, can also be filled on two separate lines in the range of 500-1250kg at speeds up to 180 big-bags per hour.

This flexibility enables Vlaeynatie to offer an unrivalled service precisely tailored to the needs of their clients.

Building corrosion resistance

For each new project, Vlaeynatie provided a detailed and demanding specification. This not only embraced the types of products anticipated, the output needed and the potential bag and pallet sizes, it also covered their own special corrosion prevention requirements. 

The Concetti lines operated by Vlaeynatie include the extensive use of stainless steel (AISI 316 and 304 grade) for material contact parts, and a special two-coat polyurethane paint over an epoxy base after careful sand blasting for all carbon steel surfaces. Proprietary components not already corrosion resistant were treated with a polyurethane enamel.

Stainless steel cable trunking and stainless-steel nuts and bolts are used throughout with stainless steel pneumatic cylinders. Pneumatic components are located inside sealed, air-tight plastic boxes, and plastic fittings used wherever possible. Any unnecessary aluminium or copper/zinc/brass components were avoided. 

Geared motors were supplied with the manufacturers anti-corrosive treatments and palletisers equipped with a pressurised chain lubrication system.

Control enclosures were supplied with a dry air connection to maintain a slight positive pressure and so avoid the entry of airborne dust. All electrical components (sensors, push-buttons, electrical terminal boxes) are suitable for a corrosive environment.

Cleaning and maintenance

Designing systems to resist corrosion, is however only part of the solution. Good housekeeping and maintenance are essential. Quick-release and electrically interlocked access doors are provided at key transfer points to allow inspection and cleaning to take place between products. This removes any residues and prevents product build-up.

Facilities are also provided to thoroughly wash down internal material contact surfaces through the load hopper, feed device and weighing system with a special quick release attachment for the bag holder to entrain and direct the contaminated water to a drainage point. This internal washing with water is undertaken periodically through the year in combination with deep cleaning to avoid any possible cross-contamination.


Van den Broeck said traceability is also starting to become more important. 

“We provide already each bag with a bar-code so that in case of a calamity it can be traced when and where the product was bagged. For some industrial fertilisers QR codes are already printed on each bag with all relevant information,” he said.

The lines are also equipped with, or were supplied predisposed for the later fitting of, label applicators or ink-jet coders to apply date/time or batch coding information.

Additionally, loaded pallets can also have a label applied. 

Big bag filling

In some markets bulk bags are preferred to 25 or 50kg bags. Vlaeynatie operates two Concetti high speed bulk-bag filling lines for bags of capacities between 500kg and 1250kg.The most recent line handles single loop bags of 600, 1000 or 1200kg capacity.

The woven PP bags have an inner PE liner which is automatically heat sealed after filling and the line operates at speeds up to 180 bulk bags per hour.

Factory testing

Concetti manufactures complete in its plant in Umbria. The company’s ISO 9000 Quality Assurance, in-house fabrication and advanced painting facility gives high levels of control over the exacting surface treatments required by Vlaeynatie.

In addition, factory acceptance testing in Italy involving the clients’ own products, bags and pallets gives an opportunity for the user to check that the lines meet the performance figures claimed but also that access, cleaning, and corrosion prevention techniques are all satisfactory. Any last-minute unforeseen issues can then be addressed in a pre-shipment review.


After market support includes teleservice via modems connected to each system to allow Concetti technicians to monitor the plant operation in real time and assist with fault finding.

Because of increasing energy costs, fertiliser prices are currently at levels not seen since the 2008 global food crisis and the work of Vlaeynatie in providing a flexible service to major global producers is helping meet the continuing robust demand for fertiliser, ensuring crop yields are maintained and food shortages avoided. 

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