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Figure 5. (A) Freeze dryer bell valves in closed position. (B) Freeze dryer bell valves in open position.
To freeze-dry samples
- Cut open the sealed sample bags and fold the top edge over to keep the bag open.
- Take the top of the bell off of the dryer and arrange samples in the bell, making sure no sample bags are pinched closed.
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- Open the vacuum valves slowly so that you do not cause a large rush of air to blow the samples around. Figure 5A shows the configuration to dry samples and Figure 5B shows the configuration for loading and unloading samples.
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- Flip the "On" switch located on the right side of the
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- Freeze Dryer.
- Press the "Auto Refrigeration" button (Figure 6A) and then the vacuum button (Figure 6B). The temperature will start to drop and the vacuum pump will turn on.
- When the temperature drops to –40°C, the vacuum is created in the bell and the pressure drops.
- Expect the temperature to be between –42° and –52°C and the pressure to be ~0.350 mBar.
- The indicator lights (Figure 6D) show how the cooling and pressure reduction are progressing. When all indicator are lights are on the freeze dryer is at its peak performance.
- If there is an error the red "Alarm" light will turn on. Press the "Menu" button (Figure 6C) to view it and clear it if necessary.
- After samples are dry, slowly open the valves to
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- release the vacuum in the bell. Remove the samples from the bell and store them inside the desiccator until they are ready to be ground to prevent reabsorption of moisture.
Figure 6. Freeze dryer control panel.
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