Principle of Operation

How Artisans’ Rototherm® Works

Shorter residence times reduce product degradation

Rototherm®’s high-speed rotor creates centrifugal force, which keeps the feed against the heated cylinder wall. A turbulent thin-film between the rotor blades and wall covers the entire heated surface at all times, independent of the feed or evaporation rates.



The turbulent thin or wiped film creates high heat transfer efficiency, minimizing the area required for evaporation. The film is continuously renewed by the incoming feed as the progressively more concentrated material moves towards the bottoms discharge nozzle. Product residence time in the Rototherm® is generally measured in seconds, minimizing degradation of heat-sensitive materials.

Artisans’ Rototherm® allows for up to 99% evaporation in a single pass and can concentrate dilute solutions to powder. Dry spots are eliminated because the process wall, unaffected by gravity, remains fully wetted at all evaporation rates.

When used as a continuous reactor, Rototherm®’s multiple feed points and temperature zones, controlled residence time, and simultaneous evaporation of reaction by-products provide total flexibility for complex reactions. Rototherm®’s short residence times allow reactions to be run at higher temperatures than conventional reactors, increasing the rate of reaction without compromising product quality and yield.

Application-Specific Design Ensures Higher Performance

Artisan designs each Rototherm® for optimum performance for its specific application. Rototherm®’s can range in size use from .25 ft² to 250 sq. ft. of heated surface. A single unit can evaporate up to thousands of pounds of material per hour. Rototherm® jackets can be designed for hot water, steam or hot oil heating. Construction materials include stainless steel (300 series and Duplex), carbon steel, nickel, Inconel®, Monel®, Hastelloy®, and titanium.

Rototherm®Application-Specific Designs

Rototherm® E: Designed to concentrate a liquid feed material to a flowable liquid or slurry
Rototherm® P: Designed to dry a liquid feed material to a free-flowing solid or powder
Rototherm® D: Designed for slow-speed, diffusion-limited post vacuum drying of a free-flowing solid material (this product is still in development)
Protherm: A special laboratory/pilot scale version of the Rototherm® E, designed as a continuous alternative to glass rotary evaporators