Manual

Operating Manual Freeze Dryer ALPHA 1-4 LDplus / ALPHA 2-4 LDplus Description of the Freeze-drying Processes  25
3. Description of the Freeze-
drying Processes
3.1. Separate Freezing and Drying Outside the Ice
Condenser Chamber (Process B) on Shelves
It is also possible to dry the product outside the ice condenser
chamber. In this case, the product has to be frozen e.g. in a deep-
freeze.
Possible water residue is removed from the ice condenser
chamber. The drain valve is opened so that the water residue can
drain off. The ice condenser chamber should be wiped out if
necessary.
The refrigeration compressor and the vacuum pump are activated
via the control system to start the pre-freezing of the ice condenser
and the warming-up of the vacuum pump. The valve is closed
during warming-up of the pump. In case the unit is not equipped
with an electromagnetic pressure control valve we recommend to
use a manual stop valve. Without such a valve the vacuum pump
must not be warmed up.
The rack is set onto the base plate. With small samples it is
recommended to pre-cool the shelves. In this way, a partial thawing
during the evacuation process is avoided.
When freezing and drying is performed separately outside the ice
condenser chamber it is directly started with the main drying
process.
As soon as the shelves with the frozen samples have been put in,
the unit and the drying chamber are sealed and the process is
started. To do so, the main drying process has to be activated in the
control system so that the pressure control valve opens and the
main drying process starts (see chapter 5.6).