Greif-Velox ValvoDetect: No product loss and no contamination during filling
Leaking packaging presents a very critical challenge, especially when it comes to food. As such, filling food powders requires particular care to ensure that no product is contaminated and that no pallets are rendered unusable. For this reason, Greif-Velox developed the optical measurement system ValvoDetect: it ensures that faulty bags can be identified and removed from the filling line at two points during the bagging process. This can prevent contamination and the costs associated with customer complaints.
Protecting the product is essential in the food industry. However, as Greif-Velox discovered in talks with its customers, powder manufacturers keep having the same problem: after the bagging process, sometimes individual bags are not sealed correctly. The consequence: An uncontrollable escape of product that contaminates entire pallets. To prevent an otherwise flawless product being sent back due to individual faulty bags, dissatisfied customers and damage to the brand reputation of the manufacturer, the Greif-Velox development team analyzed the situation: what is the cause of bags not being properly sealed in the filling process?
Development team solves problem the bagging industry has been facing for years
Greif-Velox not only produces filling machines, but also full-line systems including conveyor technology, palletization and load-securing equipment in line with customer requirements. Its development team specializes in solving problems that the industry has been facing for years. In the case of incorrectly sealed bags, the development team headed by Dr. Alexander Mildner found that the problem was not with the sealing process itself. Indeed, according to a study conducted by TH Lübeck, the ultrasonic sealing process used by Greif-Velox delivers up to 60% greater resistance to tearing when compared to conventional methods. Rather, the source of the problem lies in the positioning: In some cases, the bags were positioned incorrectly on the filling spouts due to deviations or faulty settings of the bag carriage immediately before the sealing process. Depending on the angle, this can mean that one side is not completely sealed, allowing the product to escape and ultimately contaminating the entire pallet.
ValvoDetect detects incorrectly placed bags before welding
To prevent this problem, Greif-Velox initially developed the ValvoDetect feature, 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 this is not the case, which would mean that the sealing process might not be completely accurate, the system can perform three predefined actions.
One action would be for the machine to stop so that the operator can readjust the bag carriage settings, ensuring that subsequent bags are in the correct position and can be sealed properly. Another action would be for the machine to only stop if a predefined deviation percentage is reached, or to get the machine to automatically remove the affected bag from the system before it reaches the pallet. The latter option is particularly advantageous in cases where machine downtime has to be kept to a minimum. Furthermore, it is also possible to merely statistically record bags for which the sensors identified an irregularity without further action. In this way, the right parameters can be defined and preset for each type of product and each bag size. Customers report that the use of the optical measurement system has lead to annual savings of EUR 20,000 in recall costs as well as EUR 8,000 in cleaning costs.
After ValvoDetect had been sufficiently tested in this development stage and been in operation with customers, the development team was able to precisely examine the bags that were incorrectly positioned in the sealing process, and they were labeled or separated accordingly. The result: a significant number of bags were not in the wrong sealing position due to certain settings, for instance the bag carriage settings. Rather, it was because they were picked up incorrectly right at the start of the process. This means that the filling process can be made even more efficient by separating out the faulty bags even before the filling process and not just shortly before the sealing step.
High savings in cleaning and reclamation costs
On the basis of this observation, the team at Greif-Velox updated the ValvoDetect system and equipped it with additional sensors in the front part of the system: 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 correctly. To do so, the sensor lights check whether the edges of the bag are in place. If they are pressed in or ripped, or if the bag has not been opened properly, the sensors pick it up. In this case, the damaged bag is discharged, meaning it does not proceed to the next steps 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. Alexander Mildner about the ValvoDetect, which is now patented in Germany. “In this way, it is checked right at the beginning of the bagging process whether bags are correctly positioned in the system and, if they are, whether the valve is positioned correctly for sealing after filling. This enables maximum process efficiency and more customer satisfaction.”
