Common Product Dispersion Challenges While Filling Bulk Bags
Hi, I’m Chris Wheeler, Sr. Material Science Engineer here at Conitex Sonoco. I’d estimate that at least once a week I work with a customer on a problem that the root cause is improper product dispersion when filling a bulk bag. What I mean by product dispersion, is the uniform distribution of the flow of material into the FIBC, specifically in the corners.
If you notice the following issues with your FIBCs during the filling process you probably have a product dispersion challenge:
- First thing you will notice is you don’t get all the product into the bag and you are not making the weight goals for that product, granted this could be due to other factors but best to check for dispersion first.
- Secondly, the stacking or stability of the FIBC, without properly getting into the corners of the bag it creates an uneven surface at the top. Any bags stacked on this surface will start leaning and, in some cases, fall over creating a very dangerous environment for anybody having to handle the bags.
- You will also be able to notice the product coning at the top of the bag, based on the angle of this cone, or as we refer to it… “the angle of repose¹”, this can back the product up into the filling machinery resulting in slowing, or stopping, the flow of material into the bag.
- Lastly, trying to push the product into the corners can be troublesome and when operators must do this it slows overall productivity.
What are some common causes of poor dispersion?
- The most common I have seen is when baffle bags are used, the baffles, which are used to help a bag keep its square shape also can stop the product flow into the corners.
- Additionally, the angle of repose is also a common misunderstanding, this can be different depending on the product going into the bag, it is important to understand what this is for your various products.
- Improper bag size is another cause we have seen… “Bigger is better” in most cases when talking about the top of an FIBC…sizing a bag and not taking into account the angle of repose usually results in poor product dispersion.
- Lastly, poor Handling and filling procedures can cause even a well-designed bag from properly being filled efficiently.
Is there anything I can change in handling/ filling to fix the issue?
- First thing to think about is “Do you have head space for a cone top bag?” solving the issue could be as simple as making a larger top to accommodate the angle of repose
- Or, do you have room to add a vibration table? Vibration tables do a great job of leveling most materials.
- Another easy, but less efficient method, is to take the forklift and move the bag up and set it down to push the product down.
- Lastly the lest efficient or Worst case scenario is to remove the spout and manually push the product to the sides.
What if that doesn’t solve it?
- Start by checking out the bag design you are using, maybe modifying the top…the size or the bag style can help with this.
- Also, If you have a baffle bag and cannot remove the baffles, there are solutions that will work for your product, finding the right one will require a more in depth understanding of the product properties, however.
Why is it important to have good dispersion?
- Firstly the Safety of the operators dealing with these bags, especially when stacking, is the most important reason for good dispersion
- Secondly is Getting all your product into the bag efficiently
- Then, getting all the product into the bag in the most cost effective manner
- Also, increased productivity by removing excess time spent on handling each bag
- And Lastly, it is very important when starting this process to talk to a bulk bag exert to point you in the right path, every application and process is different and what worked for one operation may not be the best for yours. In most cases we highly recommend an onsite visit by one of our experience personnel to develop the best solution for you.
¹ Wikipedia contributors. (2018, December 10). Angle of repose. In Wikipedia, The Free Encyclopedia. Retrieved 00:36, February 7, 2019, from https://en.wikipedia.org/w/index.php?title=Angle_of_repose&oldid=872977402
Angle of Repose illustration. Sand pile cut from Andrew Dunn's Sand sorting tower.jpg photo (File:Sand sorting tower.jpg). Font used: Batik Regular. Made it myself using Paint and the Microsoft Word Drawtools (cause I'm that cheap). Captain Sprite 04:27, 29 May 2007 (UTC)
Tags: Flexible Packaging