Bag filling

drumanuel
(not verified)
Posted in: , on 22. Oct. 2003 - 20:28

i am looking for help in super sack filling. particle size of the product i am making depends on several factors in the plant that econimics determine. basically, when the plant runs faster, a larger percentage of smaller particles are made. my thinking originally was that filling the bags would be even easier, but i was wrong. the bags are filled by pouring in from a screw conveyor being fed from a paddle dryer. the sack is hung and the lifting platform provides vibration (at times constant, other times not). i read some of your articles that say smaller particles will restrict air flow for degassing and that constant vibration may give initial bulk density reductions, but may "float" the large particles in the end resulting in a net reduction. The average particle size of the polymer is 150 microns. the major shift i see is an increase in the particle range of 40-100 when i speed the plant up. the solids tend to "cone' in the top of the bag and have trouble reaching the fill target. what do you believe is going on here and how can i address the problem without changing how the front end of the process works?

also, super sacks are cleaned and reused. the used sacks fill poorly as well. could this be from old particles restricting the air flow out of the sack?

thanks for your help

dru

drumanuel@albemarle.com

Re: Bag Filling

Posted on 24. Oct. 2003 - 08:35

Control and Metering uses a patented Coned Lift table which forces the ingredient to the bottom corners of the bag. The coned vibration table descends, the center column of ingredient collapses and levels the ingredient, producing highly compacted corners and a flat surface. Low frequency, high amplitude provides maximum tamping, medium frequency low amplitude vibration provides maximum densification.

You are correct you do not want constant vibration. Your current method of hanging the bag during the filling process is good as it stretches the bulk bag 3-5% and makes it a more stable package.

However, your method of densification is the problem. The Cone Densification Table will flatten the top layer of product in the bulk bag, and enable you to fill the bag to the maximum capacity. A flat vibration table will not achieve this result, we refer to it as 'minimum densification' and only propose flat table vibration for ingredients that have less than 10% difference in tamped and untamped bulk densities.

http://www.bhindust.com/controlmete...principles.htm

Hope this helps. (If you are at the Dayton facility I can be there tomorrow!)