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Difference between revisions of "Active Freeze Dryers"
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[[File:Active_Freeze_Dryers.jpg|thumb|right|200px|Active Freeze Dryers]] | [[File:Active_Freeze_Dryers.jpg|thumb|right|200px|Active Freeze Dryers]] | ||
[[File:Freeze_Drying.jpg|thumb| | [[File:Freeze_Drying.jpg|thumb|right|200px|Freeze Drying]] | ||
The '''Active Freeze Dryers''' are mainly used for freeze dying process. The freeze dying process is widely used in recent times. | The '''Active Freeze Dryers''' are mainly used for freeze dying process. The freeze dying process is widely used in recent times. | ||
Freeze-drying or commonly known as Lyophilization is a gentle, but technically complex drying process during which moisture is extracted from the frozen goods under vacuum conditions. So, many liquid active pharmaceutical ingredients for the pharmaceutical industry are quickly deep-frozen at temperatures of -70 to -100°C. Then, the frozen material is dried in a vacuum chamber. The ice evaporates at under pressure without becoming liquid - it sublimates. The water vapor is then extracted at increased vacuum and higher temperatures. For some types, the encapsulation of the glass bottles containing the ingredient is carried out under clean room conditions. Of all types of drying, freeze-drying leads to the least product changes and losses of ingredients. The Freeze Dryers operate in 3 steps: freezing, main drying, final drying. As from the second step, a vacuum pump is connected to the drying chamber to initiate the sublimation. Here, extreme parameters are reached. The vacuum sensor must withstand 5 x 10-3 mbar. This means no external particles must enter into the drying chamber, as they would contaminate the product. | Freeze-drying or commonly known as Lyophilization (executed by [[Lyophilizers]]) is a gentle, but technically complex drying process during which moisture is extracted from the frozen goods under vacuum conditions. So, many liquid active pharmaceutical ingredients for the pharmaceutical industry are quickly deep-frozen at temperatures of -70 to -100°C. Then, the frozen material is dried in a vacuum chamber. The ice evaporates at under pressure without becoming liquid - it sublimates. The water vapor is then extracted at increased vacuum and higher temperatures. For some types, the encapsulation of the glass bottles containing the ingredient is carried out under clean room conditions. Of all types of drying, freeze-drying leads to the least product changes and losses of ingredients. The Freeze Dryers operate in 3 steps: freezing, main drying, final drying. As from the second step, a vacuum pump is connected to the drying chamber to initiate the sublimation. Here, extreme parameters are reached. The vacuum sensor must withstand 5 x 10-3 mbar. This means no external particles must enter into the drying chamber, as they would contaminate the product. | ||
== | ==Why Active Freeze Dryers are required?== | ||
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. | 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. | ||
== | ==Advantages== | ||
* Active Freeze Dryer enables to produce at low temperature and low pressure a lump-free, free-flowing, freeze dried product. | * 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. | * 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. | ||
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== | ==Typical Applications== | ||
* Temperature sensitive materials | * Temperature sensitive materials | ||
* Delicate structured materials | * Delicate structured materials | ||