In the past, you’d get your hands dirty while sorting potatoes. Nowadays, during this process, a cloud of fine dust drifts through the air like a grey mist. This is released in large quantities during fully automatic sorting. The Dutch potato cultivation company, De Lugt, was recently on the market for a new sorting line. So, they asked Jongejans to design a total anti-dust solution that puts an end to this murky haze.

Last year, De Lugt decided to invest in further mechanization. This decision was made as a result of the shortage of labor. De Lugt is a true family business and dates back almost 100 years. In 1928, great-grandfather, Cor de Lugt, arrived on the Dutch island of Texel from the Hague.

He became a farmer and evolved into a smart, skilled businessman. “He built a large warehouse that could store considerable quantities of potatoes. It boasted the first weighbridge on the island as well as the first oil fuel tank. He also automated many things.” That’s according to fourth-generation De Lugt cousins, Matthijs and Bart.

This older De Lugt generation was somewhat skeptical about this latest investment. “The mechanical sorting system still worked fine. My father didn’t really deem it necessary to innovate, but now he’s very enthusiastic. He thinks it’s unprecedented; he’s changed his mind completely,” says Matthijs. The potatoes aren’t shaken anymore.

Yet, there’s still some fine dust floating around while the potatoes move along the sorting line. That causes a few issues in the machine’s optical section. That’s why Jongejans was called in. They had to take care of the dust and dirt that collected during the sorting process’ various steps. They also had to ensure optimal air quality in the warehouse (see insert).

Dust-free sorting process

Once harvested, the potatoes are dried out, crated, and kept refrigerated. When further processing is required, the crates are dumped in a bunker and sent, via a conveyor belt, to a so-called hedgehog belt. That removes any coarse dirt, straw, and clods. The spuds are then distributed to the optical sorter.

Jongejans encapsulated these bunkers and hedgehog belt to screen off the dust sources and prevent air pollution. A technique called Windshifting is employed before the potatoes reach the optical sorting machine. This method combines blowing and extracting air, resulting in an extremely clean product flow.

In the optical sorter, it’s crucial that the air is dust-free. The machine can then grade the potatoes correctly. Good extraction is, therefore, vital. After the potatoes have passed by the cameras, a stream of air blows to the correct outlet. The fine dust released in this process is removed via an extraction system. It’s then returned to the room as clean air.

That ensures both a pleasant working environment and a dust-free space. The cousins consider this a significant improvement. “Mechanical sorting was always very noisy, with that ever-present grey cloud. Now it’s quiet. And we have fresh air.”