Although the vacuum freeze drier should only be operated by the FNH technician, this video for demonstration purposes, will show you how this equipment is operated under standard operating procedures.
To turn on the vacuum freeze drier, turn both the vacuum compressor and tray drier switches, which are located on the left side of the machine, to the on position.
wait approximately 20 minutes for the water collector to cool down to operating temperatures of
negative 52 to negative 53 degrees Celsius from room temperature
While the collector is cooling down
We can insert the sample holding trays
To insert a tray first slide it into one of the shelves and push it all the way to the back
Then attach the thermal couple on the tray to the machine
Once attached the indicator display will show which shelf the tray is placed in and what temperature the tray is currently at
samples are first placed into flat-bottomed containers and completely frozen until no free water is present
a large container surface area is preferred because this helps accelerate the drying process
Different samples also require different freezing temperatures and/or freezing times due to different sample composition
samples with higher solute content typically requires longer freezing at lower temperatures
When the sample is ready to be dried after freezing first cover the container with aluminum foil or parafilm
Then poke tiny pin sized holes into the covering to allow moisture to escape
The container used in this video is only for demonstration
purposes and does not contain any actual sample
When the samples are ready you place into the freezer and close the door by turning the handle Clockwise
Then twist the vacuum release valve into the closed position
Press the vacuum button to Initiate the drying process
Observe the sample to see if any bumping or foaming occurs
sample bumping indicates incomplete freezing
in this case the sample should be removed from the freeze dryer and frozen again to ensure that the sample is completely frozen
Scan the vacuum display to see the values, the display will start off showing high with no numeric reading
this should quickly change to a numeric value and the values will drop eventually over the processing period
the processing period can take anywhere from hours to days
When the vacuum gets to 0.133 Millibars heat can then be applied to speed up the sublimation process
To apply heat first press the blue run/stop button
the letter R should appear in the indicator displays followed by Setpoint and the temperature
The temperature can then be increased or decreased with the two green buttons
usually lower temperatures such as around room temperature are preferred as this maintains the integrity of the sample
the vacuum and temperature LED Lights indicate the performance of the vacuum compressor and water collector
at maximum performance all LED lights will be lit
at critical performance levels only one set of
red LED Lights will flash accompanied by an alarm to indicate that the process needs to be restarted from the beginning
When the vacuum display indicates about 0.05 Millibars the vacuum can be stopped and the samples can be checked
0.03 to 0.02 Millibars is the baseline
to stop the vacuum first press the vacuum button
Twist the vacuum release valve to the open position to release the vacuum
The black tube connected to the water collector can also be unplugged to speed up the process
When the hissing stops the door should open easily and samples can then be checked to see whether it's finished drying
To defrost the collector press on the blue refrigeration button to turn off the refrigeration system
Then open the lid to the water collector, and the ice will melt and drain out of the black tube at the bottom
Caution to prevent injuries do not touch the cold collector with bare skin
The oil used to run the vacuum pump needs to be changed every one to two months depending on usage
To change the oil open the larger twist cap on top
Then open the smaller drain valve on the bottom to drain out all the oil
Close the drain valve before pouring in 600 milliliters of new oil from the top
The Written operation instructions for the vacuum freeze dryer can also be accessed on the left side of the machine
Thank you for watching