Separate Freezing And Drying Outside The Ice Condenser Chamber (Process B) With Sealing Device - Fisher ALPHA 1-2 LDplus Operating Manual

3.2. Separate Freezing and Drying Outside the Ice
Condenser Chamber (Process B) with Sealing
Device
20 • Description of the Freeze Drying Processes
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).
When the pressure is lower than the pre-selected „ Safety pressure
heating unit" the heating of the shelves is activated. The heating unit
continues to be switched on until the nominal value of the shelf is
reached.
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.
The sealing device is used to seal injection bottles under vacuum or
inert gas with ribbed rubber stoppers. Depending on the type of
sealing device the bottles are sealed on 1 to 2 shelves. To do this, the
shelves are moved against each other by a pressure plate using a
spindle.
The height of the pressure plate must be adjusted according to the
height of the bottles. To do so the threaded pin for height adjustment
is removed. The threaded rod is screwed into the lower shelf until its
slotted head is on the same height as the rack (upper edge).
Operating Manual Freeze Dryer ALPHA 1-2 LDplus