The carrots go straight from the calibrator to a vibration table that discards any carrots that do not have the appropriate length.
Now we begin the actual packaging process. All the weighing machines have a hopper, also known as a “lung”. The purpose of these “lungs” is to store carrots so that the weighing machines always have a sufficient amount of produce to ensure that the weighments are as accurate as possible. There are two types: the large ones, located right at the entrance of the packaging plant; and the small ones, one for each weighing machine, used to stack the produce (as you can see in the image).
Once the carrots reach the weighing machines, they are distributed among independent channels, each of which leads to a different scale. All our weighing machines have 8, 10 or 12 scales.
Each weighment is made by combining the weight of all the scales and subsequently unloading the combination of scales that offer an exact value based on a preprogrammed weight (our machines can make weighments that vary between ½ kg and 25 kg). Using this method, we guarantee a maximum error of 0.5% at a speed of up to 35 bags per minute. Once the adequate scales have been selected, they open at the bottom and the carrots fall onto a transversal conveyor belt that carries them to their final packaging.
All our bag fillers can be adjusted to different packaging formats (from ½ kg to 15 kg) and take no longer than three minutes to switch from one format to another. Each bag filler is supplied with plastic rolls known as half-tubes, which contain rolled up bags in two seperate layers (the front layer and the back layer).
Now we will explain how a bag filler works. As we have already pointed out, it feeds on plastic rolls. Its height is adjusted depending on the desired format. When a photocell reads the mark that the rolls have on each bag, the filler stops to cut it and seal it on both sides. Then it opens the bag and fills it with carrots, and finally seals the only part that is left: the top.
That is it with regard to the bags, but we also produce carrot trays in flow-pack wrappers. This process is slightly more complex. An automatic tray feeder places the trays, one by one, on a conveyor. Meanwhile, the weighing machine has already loaded the carrots into a tank, which vibrates to place the carrots in a horizontal position and then opens a door at the bottom, dropping carrots into the trays.
Finally, a conveyor carries both bags and trays to a worker, who packs them in cages (which is what we call the moulds for preparing the pallets) or in boxes, depending on the format we are working with.