Heidolph VAC control automatic - Manual (Page 53)

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Depress "Set" key, "CAL" is displayed.
Depress arrow key "down", present pressure appears in the "Act Vac"
display. "Set Vac" display shows "LO".
Copy vacuum gauge reading with arrow keys.
Complete calibration by hitting the "Set" key
INFORMATION ABOUT DISTILLATION SETTINGS
Using a rotary evaporator for thermal cracking of substances, some basic considerations should be
made to achieve the best results possible. Optimize settings as described below:
6. Rotary speed of evaporator flask
Raise distillation speed by raising rotational speed. This method cuts distillation time and protects
the substances handled.
7. Temperature difference between hot bath and vapor
This temperature difference should at lease be 20 K to achieve adequate distillation speed. If
acceptable by thermal stability of the substances handled, you even may raise temperature
difference.
Rule of thumb: double temperature to double distillation speed.
8. Temperature difference between vapor temperature and
coolant
This temperature difference should be no less than 20 K to guarantee adequate condensation.
With low temperature difference, effectiveness of solvent recovery drops. Choose an as high as
possible temperature difference in particular for high-boiling substances. .
9. Choose vacuum regulation mode and do respective
settings
9.1. "Manual" vacuum regulation mode
The "Manual" mode features the following parameters:
-
separation of substances in a mix within physical limits
- no optional equipment needed
- manually select pressure when distilling mixes of substances
- high repetition accuracy