Equipment » Thin–Film Dryers » Liquid-to-Powder

Rototherm® P dries fluids to free-flowing powder in one step

Artisan’s Rototherm P uses thin/wiped film evaporation to dry liquids or slurries to a free-flowing solid powder in a single pass. For many applications, it offers significant benefits over spray dryers and lyophilizers.

20 ft² Rototherm® system for drying a nutraceutical

Benefits
Cuts energy consumption by a factor of two or more
Rototherm P evaporates liquids by up to 99% in one step. This can eliminate the pre-concentration step often needed prior to spray drying. Also, Rototherm P eliminates the significant energy required to heat up large volumes of air needed for spray drying.
Removes spray dryer bottlenecks
Rototherm P concentrates heat-sensitive foaming products, increasing dryer capacity and saving energy.
Reduces dust
Rototherm P can minimize or eliminate the need for expensive dust collection systems.
Features

(rotor)

To deliver these benefits, Rototherm P incorporates these special, custom-designed features:

  • Robust mechanical design to handle higher torque requirements
  • All-welded ribbon blades allow space for free solids flow
  • Special extended auger section for powder discharge
  • Larger product outlet to facilitate ease of powder discharge
Rototherm P Operating Principle

Rototherm® counter-current principle

  • [1] Solvent Vapor Out
  • [2] Process Wall
  • [3] Rotor Blades
  • [4] Feed In
  • [5] Heating Medium In/Out
  • [6] Bottoms Discharge

Centrifugal force produced by the high-speed rotor blades [3] holds a thin film of feed material [4] against the heated process wall [2]. This film is continuously renewed by the incoming feed [4] as the progressively more concentrated material is displaced toward the dry solids discharge nozzle [6]. The product ultimately changes to a free-flowing solid before exiting the evaporator. High vacuum is maintained in the system to minimize processing temperature. Degradation of heat sensitive materials is minimized because residence time is generally measured in seconds.

Rototherm P units are designed for counter-current liquid/vapor flow (the liquid and resulting vapor travel in opposite directions) within the heated process section to permit nearly complete drying.