ATFD: Agitated Thin Film Dryer


    No corrosion & reduced need for maintenance


    Good heat conductivity (k-value)

    Due to its inherent design features, it is ideal for thermal treatment of solutions and heat sensitive products, where reduced operating temperatures and vacuum operating pressures are desirable. The typical Agitated Thin Film Evaporator consists of a tubular heat transfer area with an external heating jacket and a fast-revolving, inner rotor with flexible or rigid wiper elements. The driving speed is adapted to the product being handled, its particular specifications and task.

    The feed product is evenly distributed by the rotor and its wipers over the heating surface, forming a thin liquid film of uniform thickness. Highly turbulent swirls are produced at the tip of the rotor blades and wipers with intensive mixing and agitation of the product, as it comes into contact with the heating surface. This assures excellent heat transfer combined with constant renewal of the product film and provides an even heating and short residence time of the product through the heated zone.

    Key Advantages

    • Good heat conductivity (k-value), even when working with highly viscous and contaminated products
    • Minimal thermal stress, thanks to low operating capacity, therefore a short dwell time (10-20 seconds of mean dwell time)
    • No dead zone, therefore overheating prevented and perpetual high product quality guaranteed
    • Continuous mechanical cleaning of the heating surface prevents incrustations
    • High evaporation rates, due to highly turbulent film and large difference in temperature
    • Gentle evaporation, due to short residence times, rapid conveyance in the heated zone and the constant product film renewal, happens often
    • Combined with suppressed boiling points due to operation under vacuum
    • Reduced need for maintenance because of sophisticated bearings and shaft sealing parts
    • Shorter downtime and assembly time for maintenance and inspection
    • No corrosion as outside surface is usually made of stainless steel
    • Evaporation in one pass, no circulation
    • Small film thickness, no hydrostatic height
    • High turndown ratio and high flexibility for variation in requirements
    • Low operating pressure down to 1 micron to reduced boiling temperature
    • Single step drying because of unique designed combination of vertical and horizontal dryers
    • Effective evaporation of concentrated slurries, heat sensitive products, viscous and fouling fluids up to 99% in a single pass
    • Simple installation as the equipment is supplied skid mounted with all inter connecting piping, condensers and vacuum system
    • Single source responsibility for all project stages because of combined expertise in vacuum technology, heat transfer, evaporation, crystallization and drying – a design mix which gives optimal results


    Mainly used for difficult vaporization and heat exchange processes, especially where products to be handled are highly viscous and conventional plants can no longer meet user demands because heat transfer is insufficient. Due to the liquid film, mechanically generated on the heating surfaces, thin film equipment achieve much better heat transfer rates, even with highly viscous products containing solids.

    • To concentrate highly viscous products, polluted liquids, salt solutions, oils, resins, etc
    • As a sump evaporator for vacuum rectification columns
    • Sludge drainage
    • To continuously dry powdery residues
    • Distillation of high-boiling substances under high vacuum
    • Degassing and/or removal of volatile components of highly viscous products
    • Heating or cooling of viscous solutions
    • Improve product quality by removing colour bodies, minimizing impurities and eliminating thermal degradation
    • Increase product recovery by reclaiming additional bottoms product from overhead and distillate products from bottoms
    • Separation of close-boiling compounds
    • Enhance product recovery
    • Recovers additional bottoms product from overhead