An operator fills 44 lb. (20 kg) plastic fiber sacks at the bagging machine below the mixer and hopper.
How liquid additions are mixed with dry blends
To initiate a mixing cycle, an operator enters a preprogrammed recipe at a plant workstation. Individual ingredients, stored in outdoor granaries, are transported by chain drag conveyors to the aforementioned dry mixer for preblending.
Blended batches discharged into bins are then conveyed by either of two drag chain conveyors to the fluidized bed mixer. Load cells supporting the mixer transmit weight gain information to a programmable logic controller (PLC), which stops the conveyor once the preset batch weight has been gained, with +/- 2.2 lb. (+/- 1 kg.) accuracy.
Once mixing begins, a fluid volume of oil or molasses equivalent to 3 to 10 percent of the dry premix weight is automatically metered from a 44 lb. (20 kg.) capacity vessel and gravity discharged into the top center intake of the fluidized bed mixer.
Fluidized mixing zone improves dispersion
The machine’s fluidizing effect is achieved by twin paddle agitators rotating at 36 rpm within twin U-shaped troughs at the bottom of the mixing vessel. The counter-rotating agitators cause material from the troughs to become airborne along the centerline of the vessel where it intersperses rapidly with liquids sprayed into the "fluidized zone."
Mixing cycle times range from 10 seconds to 2 minutes depending on recipe.
Full-length, drop-bottom gates open to discharge blended batches into a hopper, which feeds a filling line for 44 lb. (20 kg) plastic fiber bags. Immediately after the bottom gates close, dry premix is loaded into the mixer, a pump refills the overhead liquid hopper and a new cycle begins.
