When entire pallets are contaminated due to improperly sealed bags, customers experience high product recall costs year in and year out. Greif-Velox’s updated optical measurement system ValvoDetect ensures that faulty bags are identified and removed from the filling line at two points before they reach the pallet. This helps prevent contamination and lowers costs associated with customer complaints.
Greif-Velox discovered in talks with its customers that powder manufacturers across all industries have the same problem: after the bagging process, individual bags are not always sealed correctly. The result is uncontrollable product escape that contaminates entire pallets.
Depending on the product being bagged, this can have serious consequences. If the bags contain food, it might mean hygiene problems as well as pest infestations. If the bags contain chemicals, contamination can result in safety violations.
The ICL Group from Ladenburg in Baden-Württemberg, Germany, reported that customers in Asia sent back entire pallets due to external contamination. “This led to yearly complaint costs of at least 20,000 euros,” reports Thomas Jörder, plant manager at ICL. “Not to mention the immaterial damage of loss of reputation when customers are not happy with the delivery.” At their location in Ladenburg in Baden-Württemberg, the ICL Group produces additives for lacquers and paints and the cosmetics and construction industries, as well as high-quality food additives. “It would be a shame to let one contaminated pallet ruin a customer’s opinion of a top quality product,” says Thomas Jörder.
To solve the problem of incorrectly sealed bags, the plant manager turned to Greif-Velox, a company that produces filling machines and full-line systems including conveyor technology, palletization and load-securing equipment. Alongside the customer, Dr. Alexander Mildner, head of Research and Development at Greif-Velox, and his development team analyzed the problem and determined that the bags were sometimes positioned incorrectly on the filling spouts due to deviations or faulty settings in the bag bracket immediately before the sealing process. Depending on the angle, this could result in one side not being completely sealed, allowing product to escape and ultimately contaminating entire pallets.
To prevent this problem, Greif-Velox initially developed the ValvoDetect, a system for the BVP gross vacuum packer, which is used before palletization and before the sealing process. Two optical sensors check whether the bag valve is positioned correctly in relation to the welding sonotrodes. If the light sensors determine that the bag is not positioned correctly and that the sealing process might be inaccurate, the system performs an action that has been predefined by the machine operator.
There are a few options in this scenario. The machine can be stopped so the operator can readjust the bag carriage settings, ensuring that subsequent bags are sealed properly. It is also possible to have the machined stopped if a predefined deviation percentage is reached, or to program the machine to automatically remove the affected bag from the system before it reaches the pallet. The latter option is particularly useful when machine downtime has to be kept to a minimum. It is also possible to statistically record bags for which the sensors identified an irregularity without further action. The right parameters can be defined and preset for each type of product and each bag size.
Using ValvoDetect, ICL has been able to save 20,000 euros from fewer complaint costs and 8,000 euros in cleaning costs. “ValvoDetect represents real added value for us,” says plant manager Thomas Jörder. “Not to mention we also have happier customers and a better reputation on the market.”
In its first stage, the development of the ValvoDetect made it possible to examine incorrectly positioned bags during the sealing process and label or separate them accordingly. “We saw from this that a significant proportion of bags were not in the wrong sealing position due to certain settings, such as the bag carriage settings. Rather, it was because they were picked up incorrectly right at the start of the process,” explains Dr. Mildner. This means that the filling process can be made even more efficient by separating out the faulty bags even before the filling process, rather than before the sealing step.
With this knowledge, Greif-Velox updated the ValvoDetect system and equipped it with additional sensors in the front part of the system. Now, once the bag is automatically picked up from the empty bag magazine and its valve is opened at the start of the filling process, the sensors check that the valve is open properly. “The sensor lights check whether the edges of the bag are in place,” explains Dr. Mildner. “If they are pressed in or ripped, or if the bag has not been opened properly, the sensors pick it up.” In this case, it is discharged, meaning it does not proceed to the next step in the filling process. Users report that with a faulty bag rate of 0.5%, they were able to get back 9,000 euros through complaints to the bag manufacturer alone and another 8,000 euros in cleaning costs.
“The combination of the sensor checks at two points makes this system particularly useful,” says Dr. Mildner about the ValvoDetect, which is now patented in Germany. “Checks for proper bag positioning occur right at the beginning of the bagging process, and if they are positioned properly, there’s also a check to confirm the valve is positioned correctly for sealing after filling. This helps us achieve maximum process efficiency and more customer satisfaction.”