Chapter 5: Using Your Freeze Dryer
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40
Original instructions
5.
To remove a container after freeze drying is complete, turn the plastic knob
on the valve to the “VENT” position, which closes the valve and vents the
container. Should backfilling with an inert gas be required, connect the gas
supply line to the vent port on the valve before turning the plastic knob on
the valve to vent position. The sample container may now be removed. In
the vent position the bevel on the valve knob should point away from the
sample port.
6.
Ampules may be flame sealed while connected to a valve by using a
sealing torch. Care must be taken not to burn the valve. An insulation
material placed between the valve and the torch is recommended.
Stoppering Vials
The stoppering operation (when desired) is performed after the freeze dry process
is complete and before breaking vacuum. To seal vials, move the Stoppering
control toward the “LOWER” position. This action allows the diaphragm above
the stoppering platen to inflate causing the platen to lower. The platen will lower
until it contacts the vials on the shelf. The rubber stoppers will be pressed into the
vials. Monitor the stoppering process by looking through the chamber door.
When all of the vials appear to be stoppered, move the Stoppering Control to the
“RAISE” position. This opens the diaphragm to the vacuum pump, which deflates
the diaphragm. Opening the Vacuum Release Control also deflates the stoppering
diaphragm. The Stoppering Control should be left in the “RAISE” position when
not stoppering. The stoppering mechanism is equipped with anti-tilt switch which
will stop the platen from lowering if it tilts more than 4°: If this happens return the
stoppering control valve to the “RAISE” position. This will deflate the diaphragm
and allow the platen to return to the raised position. Determine the cause of the tilt
condition before proceeding.
Vacuum Break/Backfilling
To open the chamber door, the vacuum must be released. To release the vacuum,
move the Vacuum Release Control to the “OPEN” position and turn off the
vacuum pump by pressing VACUUM, then Stop. The vacuum can also be
released more quickly by opening one of the sample valves on the left side of the
unit. Air enters the vacuum chamber through the Back Fill Port. When the sound
of air through the Back Fill Port is no longer audible, the chamber door is ready to
open.
To backfill the chamber with a gas, connect a cylinder of the desired gas to the
Back Fill Port. The port will accept 1/8" tubing. The bottle must be equipped with
a regulator set to 15 psi maximum. The gas can be metered with the Vacuum
Release Control and chamber pressure monitored with the freeze dryer vacuum
gauge. Allow the vacuum pump to run for a few minutes while the gas enters to
permit the back fill gas to surround the freeze dried sample. When the vacuum
pump is turned off, air will enter the system through the vacuum break valve
located between the vacuum pump and the collector chamber.
