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FIGURE 9 Pleated filter cartridges. Source: Courtesy of MikroPul, Inc.
Forder
Fluid Bed Dryer
Fluid bed dryer and granulators use hot gases to dry and/or agglomerate dry
powders. Wetproduct is sprayed into the gas stream through an atomizer or spray
arm (similar to aspray dryer). Product is dried and collected in ahopper at the
bottom of the dry chamber. After all liquid is sprayed into the drying chamber, the
dryer is shut down and the hopper removed.
Incorporation of automated cleaning can be done with fluid bed dryers and
granulators. There are many advantages in being able to CIP afluid bed dryer
including ensuring cleaning repeatability and consistency of the cleaning operation.
Additionally, CIPable fluid bed dryers can significantly reduce exposure risk
associated with operation and cleaning.
Fluid Bed Dryer Design Considerations
Many of the design considerations applicable to spray dryers are applicable to the
fluid bed dryer. Several specific challenges exist in cleaning the fluid bed dryer.
Filters are installed in the top of the drying chamber to collect exhaust particles in
the drying stream. These filters are removed and washed or if of asuitable material
(sintered metal, Teflon cartridge) may be cleaned in place.
Again, care needs to be focused on the gasket and flange design as with
spray dryers. Similar to the spray dryer, sanitary flange connections minimize the