One of the largest crate washing installations in Europe

Colruyt Group goes full steam ahead with sustainability and chooses Euro Pool System's (EPS) green, reusable folding crates. These folding crates in recyclable HDPE plastic are becoming the standard.

Empty and closed, they take up 75 % less volume in storage and transport than the classic blue rigid crates. This means a truck takes four times more crates in the same return trip. This reduces CO2 emissions.

However, this project required significant Supply Chain adjustment. Therefore, investments were made in a new crate washing line at the return centre in Halle. A crate washing line with one of the largest capacities in Europe, i.e. 18,000 crates per hour for washing own crates but also for washing crates within the EPS pooling system.


Before the installation of this new facility, there were three washing lines: a 20-year-old Bruel line and two mirrored ten-year-old Colussi lines. There are now two new Bruel washers. One Colussi line was demolished. The other one was moved several meters toward the wall, overhauled and upgraded. “We needed to scale up and process more crates", Ruben De Rop, Project Manager and Project Engineer Automation says.

The project started in March 2019 with a preliminary study. “Engineering started with conceptualisation", Ruben says. Most of the design followed "but along the way the detailed design has been optimised.” The timeline was indeed quite short. “Moreover, we combined a lot of things.” Automation, vision, maintenance, water supply, connection to the Combined Heat Power Plant (CHP), etc.

Thomas Broquet, maintenance engineer in charge of Reliability & Maintenance, co-acted as project engineer. He developed a simulation tool to dimension the installation and production at peak times (i.e. the installation is slightly oversized) but also its maintenance. The old installation required just under twenty operators per shift. “The new facility runs on three plus one people during the day and two plus one at night, depending on how busy it is.”

The installation was partly drawn out in 3D and simulated virtually. Certain components were also field-tested. Thus, an infeed belt was set up and tested for several months. They even considered what a fifth line could add. “That one turned out not to be very profitable. We checked off the impact on the overall business case with simulations and figures each time. We gain in transport. Automation implies less 'waiting' and we can deploy people elsewhere. In short, everything pointed to a positive, realistic case and a more sustainable story", Ruben says.

The new installation is much more compact, automatic, simpler. Bottlenecks in buffering are already eliminated in the future. “Sixty percent of the current maintenance cost is transport-related.” Roller conveyors require a lot of maintenance. The new systems have been well thought-out with regard to maintenance. “Through simulations, we calculated the maintenance cost and saw that it decreased by 10 %. “We also had a lot of focus on safety. The design was substantiated in consultation with the prevention department and the operators themselves", Ruben said.


The 'dirty' crates come in mixed. There is a multitude of crates on the same pallet. A decentralised vision system controls the pallet. Plastic versus wood. Afterwards, each stack is examined to see what type of crates are on it, rigid or folding. This is a preliminary sorting based on contour recognition. After this, the machine sends the cheese crates through the overhauled Colussi line and the folding crates through the folding line. Then destackers discard the new crates crate by crate on the new line. Size and height of the crates varies. One goes crosswise through the 41 cm wide line. The other goes lengthwise. Via a so-called C-turner, the crate is turned over so that coarse dirt falls out. Then everything goes randomly through the washer.

The new washing installation obtains its hot water from the CHP, which also serves to heat the buildings. “The new installation's share of energy consumption is getting smaller. We can bring down the wash temperature, which used to be over 50 °C, to 45 °C, thanks to the much better insulation of the new washers.” The Colussi machine also got additional insulation during the overhaul that significantly reduced heat losses.

A vision system verifies the cleanliness of the crate after washing. The drying process has also been addressed. In the past, crate drying was done with hot air. “For the new lines, we are working with an electric centrifuge that does not require additional heat", which is therefore more energy efficient. The washed folding crates are stacked in half-crate stacks and "tumbled" dry by means of a centrifuge. After that, everything is identified. A final vision system checks the crate type for restacking the crates to the desired final height. A forklift truck puts away the pallets.

“This modular technology also allows us to respond quickly to any new developments in crating", Ruben said. By using the cameras, "teaching" allows quick learning when changes occur. The sensors also provide a lot of data. “We collect those on a virtual server for technical analysis afterwards.”


For Project Manager Ruben De Rop, the major challenge in this project was, on the one hand, to develop a 'future-proof' design and, on the other, to get the whole thing into a workable schedule, knowing that production would be maintained in the same hall during the conversion/renovation. “Both old lines had to be constantly adjusted to keep them running while we created space, carried out earthworks and laid floors, to build the new installation.”

This article previously appeared in Engineeringnet.

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