Labconco FreeZone 4.5 Liter Freeze Dry Systems 77510 Series - Manual (Page 24)

Chapter 4: Using Your Freeze Dryer
Product Service 1-800-522-7658 20
containers or larger). The temperature required for pre-freezing is dependent on
the characteristics of the sample. Pre-freezing temperature typically is at least 10°
to 20°C below the eutectic or collapse temperature of the sample.
Adding Sample
The following procedure should be followed when using sample valves in the
freeze dry process:
1.
Connect a pre-frozen sample to a sample valve on the drying chamber or manifold
using an adapter. Turn the plastic valve knob to the “VACUUM” position to open
the valve. The bevel on the knob should be positioned toward the sample port to
apply vacuum to the sample.
2.
Before adding another sample, allow system vacuum to return to 0.133 mBar
or lower. Any combination of valves and sample sizes may be utilized at one
time provided that the system vacuum and collector temperature remain
sufficiently low to prevent melting of the frozen sample.
3.
When all the frost has disappeared from the outer surface of the sample
container and no cold spots can be detected by handling the container, the
sample is nearly dry. To be certain of low final moisture content, dry the
sample for several hours past this point.
4.
To remove a container after 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.
Vent/Backfill Port
Bevel in “vent” position
Bevel in “vacuum”
position
Adapter