Active Freeze Drying system

Freeze drying (lyophilisation) has been used industrially for decades. However, traditional tray-type freeze dryers are labour intensive. Hosokawa's Active Freeze Drying system eliminates this drawback and is a big step forward in the field of freeze drying thermo-sensitive bulk solids as well as in powder technology in general. Due to the agitated freeze drying process, different product characteristics can be improved without the need of post-processing steps.

The Active Freeze Drying system offers unique possibilities for freeze drying various types of materials in one processing step, always resulting in a fine loose powder which is directly available from the product collector. Material consistencies can range from solutions, dispersions to paste and even wet solids. The key benefits of this technology are efficiency, minimal handling and a consistent, high product quality.

Active Freeze Dryer Active Freeze Dryer

In an Active Freeze Dryer, the product is first frozen dynamically by moving it in a specially designed chamber. Whether the material to be dried starts off as a liquid, granular solid or paste, the forced motion inside the drying chamber ensures that it freezes in the form of free-flowing solid granules.

Working principle Active Freeze Dryer

Once the product is fully frozen, a deep vacuum is applied and the sublimation starts. Heat applied to the vessel jacket is effectively distributed throughout the product due to the dynamic environment. The initially coarse, frozen granules gradually shrink as the ice structure connecting the frozen material sublimes, yielding a loose powder consisting of fine, dry particles.

As the solvent disappears, the product temperature starts to rise until it equals the jacket temperature. This marks the end of the drying process. Once the vacuum has been released, the chamber is opened and the powdered product can be discharged.

Typical applications include pharmaceuticals like antibiotics, proteins, collagens, APIs and electrolytes.


  • Efficient
    The Active Freeze Drying process is less labour intensive than the traditional tray-type process. This new technology produces lump free, free-flowing powders in one single step. Consequently, the handling is significantly shorter and simpler (no manual handling or de-lumping steps), saving you time and money!
  • High Quality
    Due to this alternative and much faster method of freezing the substrate, the structure of the end product is different and in the majority of cases, will result in an amorphous-like structure with better (re)dispersibility and free-flowing properties. In addition to this, the particle size of the final product is often extremely fine and uniform.
  • Contamination-free
    There is hardly any risk for contamination, which makes the Active Freeze Dryer ideal for sterile materials.
  • Compact
    The Active Freeze Dryer is a compact piece of equipment that requires much less floor space than conventional tray drying installations which usually comprise of horizontal vessels, freezer and tray handling machinery. Hosokawa Micron has converted all of this into a single vertical dryer.
  • Broad equipment range
    The Active Freeze Dryer is available in a broad range of different sizes, from 1 up to 1000 litres.

The Active Freeze Dryer is available in several models. A few models with their typical characteristics are described below. Please note that these values are indicative only. Detailed information is available on request.

Model [l] 1 5 20 60 100 500 800 1000 1500
Max. net product volume
[l] 0.5 2.5 10 30 50 250 400 500 750
Jacket surface area [m²] 0.06 0.13 0.33 0.69 0.98 2.84 3.93 4.58 5.99
Max. sublimation capacity
at p=2 mbar
[kg/h] 0.1 0.3 0.8 1.7 2.2 7.2 9.9 11.4 13.7

The Active Freeze Drying system is built up from several items. Apart from the freeze drying chamber itself, it may consist of any or more of these ancillaries:

  • Vacuum pumps (lubricated or dry running)
  • Ice condensor (system) [option]
  • Heater / cooler system
  • Filter / product collector
  • CIP skid [option]
  • SIP skid [option]
  • Control system

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