Martin Christ Alpha 2-4 LSCplus - Manual (Page 94)

ALPHA 1-4 LSC&
ALPHA 2-4 LSC&
11 Appendix
94
Version 01/2011, Rev. 1.5 of 16/12/2013 • sb
Translation of the original operating manual
17 Drain the defrosting water via the media drain valve on the left-hand
side of the unit. To do so, connect a hose to the hose connector and
collect the defrosting water in a suitable vessel.
18 Keep the freeze-dryer open (i.e. without the lid or drying chamber) when
it is not in use so that moisture can evaporate. This increases the
service life of the vacuum sensor.
Step-by-step instructions – drying in a flask
1 Freeze the sample separately, e.g. in a deep-freeze.
NOTE
Ensure that the layer thickness of 1 to 2 cm is not exceeded, since
otherwise the drying time needs to be extended.
2 Check the ice condenser chamber and ensure that is completely free
from water residues.
3 Install the drying chamber. Prior to doing so, check whether the O-ring
is completely free of dirt particles. The ground-in stopper of the acrylic
glass bell must be greased with high-vacuum grease.
4 Ensure that all of the valves are closed.
5 Let the vacuum pump warm up 20 to 30 minutes before the freeze-
drying processes commences.
6 Connect a frozen sample to a valve.
CAUTION
After the pressure has fallen below 1.030 mbar, a frozen sample can be
connected to a valve. The next frozen sample cannot be connected to
another valve until the pressure is again lower than 1.030 bar.
NOTE
The vacuum pump always runs with maximum power.
With this type of freeze-dryer, the power of the vacuum pump cannot be
controlled.
7 The operating panel displays the vacuum, the ice condenser
temperature, and the current operating mode.
8 The end of the process is reached when the ice condenser is no longer
loaded and when it again reaches a final temperature of approximately -
50°C to -54°C. The pressure decreases as a function of the ice
condenser temperature.
NOTE
The drying time depends on the layer thickness of the sample, the solids
content of the sample, and the amount of heat that is supplied during the
drying process. In the case of a layer thickness of 1 cm, the freeze-drying
process usually takes 24 hours.