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FREEZE DRY

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Freeze Drying is the process of removing moisture from a frozen product using vacuum. ... .133 mBr Endpoint Determination Visual inspection. (cake or powder) ... – PowerPoint PPT presentation

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Title: FREEZE DRY


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Definition Purpose Process
4
Definition
Lyophilization is another word for freeze drying
derived from the Greek words solvent-loving.
Lyophilized material is easily rehydrated.
Freeze Drying is the process of removing moisture
from a frozen product using vacuum.
5
Definition
Sublimation is the freeze drying process in which
solvents, such as water, pass directly from the
solid to the vapor state.
The rate of sublimation is dependent on
temperature and pressure.
6
Purpose
Freeze Drying preserves the integrity of the
products biological and chemical structure and
activity.
7
Process
  • Prefreezing
  • Primary Drying
  • Secondary Drying

8
Pre-freezing
Slant Freezing
Stub Freezing
  • Limited surface area.
  • Not the preferred method to pre-freeze.
  • Gives more surface area to
    decrease freeze dry time.
  • Preferred method.

9
Pre-freezing
Shell Freezing
Increases the surface area to volume ratio by
spreading out the frozen product inside the
vessel.
10
Primary Drying
  • Process Requires
  • Prefrozen sample.
  • Temperature difference between sample and
    collector establishes a vapor pressure
    differential.(collector should be
    15-20 colder than the sample.
  • Heat applied to the sample.
  • High vacuum.

11
Primary Drying
Cross Section View of Valve and Flask
Frozen Sample
Water Vapor
Heat
Heat
12
Primary Drying
A Vacuum Pump encourages the free flow of water
molecules from the product by evacuating the
environment around the product. It removes
non-condensable gases.
  • Minimum Requirement - .133 mBr

13
Endpoint Determination
The endpoint of primary drying can be determined
by
  • Visual inspection. (cake or powder)
  • Measurement of condensable gasses via vacuum
    gauge.
  • Product temperature or weight.

14
Secondary Drying
The process of reducing the 7- 8 residual
moisture content still present in the visually
dry sample.
15
Secondary Drying
Isothermal desorption is the removal of bound
water from a sample. Requires a temperature
higher than ambient and 1/3-1/2 the time
necessary for primary drying.
16
Bulk Tray Dryer
  • An economical alternative to the Stoppering Tray
    Dryer when stoppering under a vacuum is not
    required.
  • Lyophilize bulk samples such as soil, liquids or
    plant materials.

17
Bulk Tray Dryer
  • 3 large shelves for bulk trays or batches of
    serum bottles, vials or ampules.
  • 200-watt heater on each shelf heats from 20
    C to 60 C.
  • LCD display of set point and temperature (C)
    for each shelf.
  • Shelves are not cooled by the Bulk Tray Dryer.
    The only cooling is from the frozen sample.

18
Bulk Tray Dryer
  • Vacuum release valve allows user to open the
    door.
  • Option to purchase with or without six-port
    support shelf
  • Option to purchase two additional heated shelves

19
Bulk Tray Dryer Accessories
Support Shelf with valves installed provides
flexibility to connect flasks and other freeze
dry glassware. It also elevates Tray Dryer above
work surface of Freeze Dry System to allow
unobstructed access to the collector.
Left Heated Shelf With Sensor Right Stainless
Steel Bulk Tray
20
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