11/01/2022
https://www.youtube.com/watch?v=LmC4dZ-3PIk
Prism Fluid Bed Coater (Bottom Spray) Basic Working:
The Wurster coating process is a bottom-spray coating process that takes place in a fluidized bed.
At the bottom of the fluidized bed, a distributor plate with a specific pattern of orifices determines the distribution of the hot fluidization airflow. This airflow is partly responsible for the motion of pellets.
Also, there are five fluid spray nozzles at the bottom of the fluidized bed.
These spray nozzles supply a liquid solution as well as an atomization airflow that breaks the solution into small droplets. The spray nozzles thus form a spray region at the bottom of the fluidized bed.
As the pellets travel through this region, they receive a coating solution in the form of droplets, and, as they move around in the fluidized bed, the liquid droplets are dried by the hot airflow to form a film layer on each pellet
Based on particle behavior, the fluidized bed can be divided into different regions. The regions are as follows.
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1) The Spray Zone,
2) The Wurster Tube,
3) The Fountain Region,
4) The Down bed Region, and
5) The Horizontal Transport Region.
During coating pellets receive the coating solution in the spray zone, and then dry as they return to the spray zone after having traveled through the Wurster tube, the down bed, and the horizontal transport regions.
In Wruster coating system as the particles continue travelling upwards, they dry and fall outside the Wurster tube back towards the base plate. They are guid...
