FTS LYOSTAR 3, Руководство оператора

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Operating your Lyophilizer FTS Systems LyoStar™ 3
18 Rev 006, 01/14
© SP Scientific 2014
Freezing / Thermal Treatment
Product samples must be frozen before the start of the drying process. Freezing can
be accomplished directly in the product chamber as part of an automated cycle, or in
a shell bath or laboratory freezer. The temperature required for freezing is dependent
on the characteristics of the product sample. Typical freezing temperatures range
between 10 °C and 20 °C below the product’s eutectic or collapse point.
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Praxair’s ControLyo™ Nucleation On-Demand Technology
ControLyo™ Nucleation On-Demand Technology is a new technology developed by
Praxair, Inc., which utilizes a series of pressurization and depressurization events
within the product-drying chamber using a gas to enable controllable instantaneous
and homogeneous nucleation of the freezing event for all product containers in the
chamber. Systems configured with Praxair's ControLyo™ Nucleation On-Demand
Technology provide the option of performing these events during the Freezing /
Thermal Treatment phase of a freeze-dry cycle.
Note: For additional information, refer to Chapter 9: Praxair’s ControLyo™ Nucleation
On-Demand Technology and/or your control system operator’s manual.
Drying Steps 1-16
Once your product samples have been frozen, moisture must be extracted from the
product through a process called sublimation. During the transition from freezing to
drying steps 1-16, the condenser is typically cooled to its lowest possible temperature
under the load. A cold condenser chamber, typically -40 °C or below, provides a
surface on which the water vapor can re-solidify during the drying phases.
Using the lyophilizer’s control system, the chamber pressure is lowered, and adequate
heat is supplied to the product samples allowing the water within the product to
sublimate. Temperature is controlled by the cooling and heating systems, while
chamber pressure is controlled via the vacuum level control valve.
An inert gas may be used for vacuum level control, if desired. When using an inert gas
for vacuum level control, be sure to use an accurate two-stage pressure regulator set
to a maximum of 1 psig. Bleed gas should be connected to the lyophilizer’s inert gas
port.
Note: SP Scientific recommends the use of nitrogen for vacuum level control with an inert gas.
Gases other than nitrogen may cause inaccurate sensor readings.
During drying steps1-16, about 95% of the product’s water should sublimate. Note
that these drying steps may take several days. When drying step 16 has completed,
both the condenser and vacuum should reach a stable low reading.
Note: For additional information, refer to your control system operator’s manual.
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A product’s eutectic point is the point on phase diagram where three or more phases are present and the temperature and
composition of the liquid phase cannot be altered without the disappearance of one of the solid phases. The reference to
eutectic point assumes that the product being frozen has a crystalline structure. Amorphous materials, which are non-
crystalline and structure-less in nature, do not have a eutectic point. Instead, they have what is referred to as a liquid-glass
transition temperature (or simply glass transition temperature). However, amorphous materials do have a similar point, below
which the product must be maintained to prevent melt-back or collapse during the freeze-drying process.