White Paper | November 12, 2012

Mixer And Blender Options For Vacuum Drying Requirements

Source: Charles Ross and Son Company

Throughout the industries, more and more manufacturers are turning to agitated vacuum systems to improve their drying processes. Three common mixing technologies are employed in various vacuum drying requirements: the Vertical Blender/Dryer, Cylindrical Blender/Dryer and Double Planetary Mixer.

Agitated vacuum dryers have a wide range of feed forms that they can accommodate – from slurries, wet cakes and pastes, to granules, pellets and powders. The characteristics of the feed, intermediate and final dried product are all important considerations when selecting the right equipment for a particular application.

Vertical Blender/Dryers feature a slow-turning auger screw which orbits around a conical vessel. The screw gently lifts material upward as it advances along the vessel walls. At the same time, materials at the upper most level of the batch cascade slowly back down into regions opposite the moving auger screw. The constant exchange of materials between the heated sidewalls and center of the blender accelerates the drying process.

Cylindrical Blender/Dryer are equipped with a ribbon or paddle agitator. Heat transfer is extremely efficient since the jacket surrounds the entire cylinder and end plates. Cylindrical Blender/Dryers are ideal for products that would persistently hang up on the trough of an ordinary U-shaped horizontal blender.

Double Planetary Mixers are commonly used for batching viscous formulations such as rubber adhesives, silicone sealants, pharmaceutical gels and highly-filled composites. These devices move material by rotating two identical blades on their own axes as they orbit around the batch on a common axis. The mixing action is very thorough regardless of product rheology. Aside from their primary use in compounding high viscosity formulations, Double Planetary Mixers are also frequently utilized as vacuum
drying equipment.

 

 

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