Thermo Scientific ModulyoD, Инструкция по эксплуатации

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You must pre-freeze the sample before placing it in (or on) the drying accessory. The
thickness of the ice (and, hence, the sample) will affect the length of time needed to dry
a given sample. In general, the thickness should be less than 10 mm.
1.4.2 THE FREEZING PROCESS
When the condenser chamber has reached a temperature of -40 °C (as shown on the
temperature display), the vacuum pump may be switched on (see Section 4). The pres-
sure in the condenser chamber then starts to drop, producing the conditions necessary
for freeze drying to occur. The pressure display will show the pressure in the condens-
er chamber.
The time required to dry sample varies and is determined by a number of factors: The
type of sample, sample mass and thickness, type of container used, temperatures of
the sample, and the condenser and system performance.
Freeze drying requires an input of heat energy to the sample to change the ice into
water vapor. When using the ModulyoD, this energy may be absorbed solely from the
surroundings or, alternatively, a heated accessory may be used to provide additional
energy input. If using a heated accessory, the accessory should not be switched on until
the pressure in the condenser chamber has fallen to 1 mbar or lower.
When deciding on the quantity of heat input required, or when you try to optimize the
drying cycle for a particular product, it is important to observe the physical appearance
of the product whenever possible during the drying process. If the product has been cor-
rectly frozen, it will usually appear to be uniform in color and compact. If the product is
uneven in color, or if signs of boiling are visible, then the product may have been incor-
rectly frozen, or may have undergone some physical change, possibly from the appli-
cation of too much heat.
A wide range of factors have to be considered when trying to optimize the drying cycle
for a given sample. To assist in this optimization, we, therefore, recommend taking note
of the rate of change of both temperature and pressure within the condenser chamber
(see Appendix C) during the freeze drying process.
1.4.3 THE DRYING PROCESS
When the ModulyoD is used as a vapor trap (for example, in gel drying applications), its
function is significantly different than that when it is used in freeze drying applications.
In vapor trapping applications, the ModulyoD acts solely to protect the vacuum pump; in
freeze drying applications, it actually pumps the water vapor from the product. In vapor
trapping applications, it is often necessary to limit the vapor flow from the system to the
ModulyoD by fitting a restrictor between the vapor source and the ModulyoD. The size
of restrictor required depends on the system. See Appendix A for detailed information on
the use of the ModulyoD as a vapor (cold) trap.
1.4.4 VAPOR TRAPPING