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ROTOTHERM® Thin-Film Evaporators (TFE)

Concentrate or dry difficult-to-handle process streams with unparalleled efficiency. The ROTOTHERM®’s robust, scalable horizontal design handles what vertical wiped-film evaporators cannot.

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Overview

Designed for the Process Streams Other Equipment Can’t Handle

The Rototherm® Thin-Film Evaporators (TFE) concentrates or dries many difficult-to-handle process streams with unparalleled efficiency. Unlike traditional vertical wiped-film evaporators, the Rototherm®’s robust, scalable horizontal design enables liquid-to-powder drying for many materials, with a low height requirement that simplifies installation.

Every Rototherm® is designed for optimal performance based on data specific to the user’s process. Size depends on the design feed rate, evaporation rate, operating temperature, pressure, and final product specifications. Equipment can be designed for pharmaceutical, food, or chemical service, and for specific location requirements including geographic and hazardous area classification. All specific design details, including pressure vessel code, temperature and pressure rating, polish, elastomers, seal type, and electrical connections, are confirmed with the user during the design phase.

Large skid-mounted horizontal industrial reactor vessel with a heavy-duty electric drive motor and gearbox, fabricated in stainless steel by Artisan Industries Inc., highlighting technology advantages in process efficiency.

Technology Advantages

Enhanced Heat Transfer

The turbulent, thin film created on the evaporator surface enhances heat transfer efficiency, resulting in rapid evaporation with little to no heat losses and keeping high velocity in the material to avoid fouling.

Uniform Distribution

Horizontal orientation ensures uniform distribution of the liquid across the continuously wetted evaporator surface, optimizing the overall process.

Preserved Product Quality

Reduces the risk of thermal degradation of heat-sensitive materials with the combination of short residence time, vacuum operation, and reduced processing time.

Key advantages of Rototherm Horizontal Thin-Film Evaporators (TFE) vs. Vertical Wiped Film Evaporators (WFE)

Heat Transfer

Approximately 20% higher heat and mass transfer coefficients. Gravity does not impact performance, the film remains fully wetted at all times.

Material Handling

Inherently more suitable for hard-to-process materials and high evaporation rates, with significantly less entrainment than vertical designs.

Cleaning & Maintenance

Easy to clean using a small volume of CIP solution. No flushing or disassembly required. Maintenance is significantly easier, leading to a lower cost of ownership.

Installation

Requires less structural height. Installation on site is easier and typically costs 20% less than equivalent vertical equipment.

What the ROTOTHERM® Is Used For

  • Concentrating and drying waste and/or products
  • Recovering solvents from waste/mixed streams
  • Preconcentration prior to spray-drying
  • Removing solids prior to distillation
  • Recovering heat-sensitive APIs, intermediates, or fine chemicals
  • Concentrating brine solutions containing PFAS
  • Continuous reactors
  • Post-reaction stripping
  • Devolatilization/dewatering/stripping
  • Process intensification by combining unit operations

How It Works

How the ROTOTHERM® Operates

The rotor blades produce centrifugal force, holding a thin film of feed material against the heated process wall.

The turbulent, thin film between the rotor blade and process wall covers the entire heated section, regardless of feed or evaporation rates. It is constantly renewed by the incoming feed, while more concentrated material is displaced towards the bottom discharge nozzle.

High vacuum minimizes processing temperature and residence time is short, reducing degradation of heat-sensitive materials.

3D cross-section schematic of an Artisan Rototherm agitated thin-film evaporator showing the feed inlet, thin-film evaporation area, vapor outlet, and concentrate outlet.

Design & Operation Principle

Co-Current Flow

Liquid and produced vapor travel in the same direction within the heated process section. Used for higher viscosity applications and to reduce liquid entrainment.

Counter-Current Flow

Liquid and produced vapor travel in opposite directions. Typically preferred for drying, stripping, or distillation to prevent reflux from traveling to the bottoms outlet.

Technology in Action

The ROTOTHERM® Running

Rototherm® TFE feature a high-speed rotor that uses centrifugal force to keep the feed material against the heated process wall. This creates a turbulent, thin film between the rotor blades and the process wall, covering the entire heated surface at all times, regardless of feed or evaporation rates.

Configurations

Six ROTOTHERM® Configurations

The Rototherm® platform is available in six specialized configurations, each designed for a specific class of process application.

Rototherm® E

Concentration / Evaporation

The most popular Rototherm® design, ideal for concentrating liquid feed material to a flowable liquid or slurry. With over 500 installations worldwide, it has been continuously improved since the 1960s to enhance processing capabilities.

Applications

Research and development teams who need to validate a process before committing to production-scale equipment.

Rototherm® P

Liquid to Powder Drying

Designed for drying slurries and solutions with dissolved or suspended solids. Widely used to produce free-flowing powders from heat-sensitive products.

Applications

Drying aqueous solutions of animal proteins from 93% water to dry powder, preventing thermal denaturing and mechanical denaturing that would occur in a scraped surface evaporator.

Rototherm® TS

Twin-Screw Extrusion Outlet

Incorporates a screw device directly into the process section, effectively discharging products without accumulation or clogging. Particularly useful for sticky, viscous, or crust-forming materials.

Applications

Polymers · Food concentrates and intermediates · Waste streams

Rototherm® Mini

Lab-Scale Continuous

Offers continuous, scalable, and cost-effective separation for R&D teams, preserving product quality, increasing throughput, and saving energy. Utilizes the same thin-film separation technology as production-scale Rototherm® units.

Applications

Research and development teams who need to validate a process before committing to production-scale equipment.

Rototherm® Reactor

Continuous Reactor

Used as a continuous reactor, providing flexibility for complex reactions with multiple feed points, controlled residence time, and simultaneous evaporation of reaction by-products.

Applications

Thin Film Saponification · Thin Film Esterification · Thin Film Polycondensation · Gas/Liquid Reactions · Conversion of Radioactive Caustic

Rototherm® Foam-Breaker

Foam-Breaking Configuration

Enhanced foam-breaking capabilities for surfactants and other foaming materials. The rotor design creates a semi-tortuous path for vapor exit while mechanically containing the liquid and foam.

Applications

Surfactants and foaming materials where conventional evaporator designs cannot maintain stable operation.

Not sure which Rototherm® configuration is the
right fit for your process? Our team is here to help.

Talk to an Engineer

Technical Specifications

Size Range, Materials & Operating Parameters

Size Range
1/8 to 225 sq. ft. of heated surface area
Operating Pressure
Below 1 mmHg to over 100 PSIG
Capacity
5 mL/min to 4,500 lb/hr of material, based on size and application
Operating Temperature
Below 100°F to over 700°F
Construction Materials
Stainless steel (300 series and Duplex), carbon steel, nickel, Inconel®, Monel®, Hastelloy®, and titanium
Every Rototherm® is designed to your process. The size of the Rototherm will largely depend on the design feed rate, evaporation rate, operating temperature, pressure, and final product specifications. All specific design details, including pressure vessel code, polish, elastomers, seal type, and electrical connections, are confirmed with the user during the design phase.
Heating Options
Hot water, steam, or hot oil — depending on operating temperature and site utilities

Advantages Over Vertical WFE

  • Gravity does not impact performance, the film remains fully wetted
  • Approximately 20% higher heat and mass transfer coefficients
  • Inherently more suitable for hard-to-process materials, high evaporation rates, and significantly less entrainment
  • High turndown ratio (10:1)
  • Easy to clean, less than 15 minutes using a small volume of CIP solution. No flushing or disassembly required
  • Requires less structural height for installation on site
  • Installation on site is easier and typically costs 20% less
  • Maintenance is significantly easier, leading to a lower cost of ownership

FAQs About Artisan’s ROTOTHERM®

A thin-film evaporator spreads a fluid into a thin, turbulent layer across a heated surface using high-speed rotating blades. This results in excellent heat transfer and rapid evaporation. Because the film is continuously renewed, materials spend very little time on the heated surface, which protects heat-sensitive compounds and improves product quality.

 

Unlike conventional distillation or kettle boiling, thin-film evaporation uses a continuously refreshed, ultra-thin liquid layer that evaporates quickly and uniformly. Short residence times, vacuum operation, and efficient heat transfer minimize thermal degradation and provide higher purity and higher yields. The self-cleaning motion of the wipers also reduces fouling and extends operating time between cleanings.

 

Thin-film evaporators reduce thermal exposure by maintaining very short residence times and allowing operation under vacuum. These conditions lower boiling temperatures and prevent degradation. As a result, pharmaceuticals, natural extracts, specialty chemicals, and other heat-sensitive materials maintain stability, color, potency, and overall quality.

 

Ready to Evaluate the
ROTOTHERM® for Your Process?

Describe your material and process goals and our engineering team will assess suitability, using your feedstock, before any capital commitment is made.

Contact Our Team

Give Us A Call

(781) 893-6800

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