Difference between revisions of "Active Freeze Dryers"

Until now most of  the freeze dryers are of the Tray Dryer  type. Despite the optimal  structure of the individual product particles the  product layer on the  plates will usually form one piece of hard baked material.  Often the  product has to be crushed after freeze drying, which may lead to damage  of the product structure. Another disadvantage is the relatively low  heat  transfer rate due to the dead state of the material on the plates.  Also the  handling of the product is quite labor intensive because the  trays have to be  filled and discharged manually. In this context active freezing came into existent. For this active freezing process a special kind of dryers were emerged named Active Freeze Dryers.

* Active Freeze Dryer enables to produce at low temperature and low pressure a lump-free, free-flowing, freeze dried product.

* The Active Freeze Dryer also has a better heat transfer rate due to the continuous mixing of the product, resulting in shortening the drying  process.

* Active freezing dryer follows such a freezing step that is simplified because it can be done in  the same vessel  instead of having a separate freezing unit, which results in  easy  handling of the product compared to it's predecessor tray dryer equipment.

* The Active  Freeze Dryer can also be used in continuous operation.

* Since the dried product  is released from the frozen material during the  drying process, these dry  particles can be collected separate from the  actual dryer.

* Temperature  sensitive materials

* Delicate  structured materials