BUCHI Rotavapo R-215 - Manual (Page 47)

6 Operation
47 R-210/215 Operation Manual, Version F
ATTENTION
Risk of overflowing.
• When you are operating with a 5 l heating bath, make sure that the controller is configured in a
way that the flask is not automatically submerged into the heating bath to avoid an overflowing of
the heating bath due to displacement. Introduce the flask manually instead.
• After the set vacuum has been reached, wait for about 1–2 minutes to see whether distillation
begins.
• If the distillation does not start, optimize the parameters (decrease the pressure gradually or
increase the bath temperature).
• Both possibilities lead to an increased distillation capacity, see also chapter 6.6.
6 .6 Optimizing the distillation conditions
Depending on the solvent being distilled the distillation might have to be re-optimized. In the optimized
case, the condenser should be steamed up to between 2/3 to 3/4, see figure below.
If this is not the case, there are two possibilities to optimize the distillation:
• When the heating bath has reached 60 °C slowly reduce the pressure. Thus, the boiling point of
the solvent is reduced and Δ T
1
increases resulting in an increase of distillation capacity.
• When the heating bath has reached 60 °C increase the bath temperature. Thus Δ T
1
increases
resulting in an increase of distillation capacity as well.
NOTE
When the bath temperature is increased, not all of the additional energy is used for distillation but a
major part is discharged into the environment due to the increasing difference between heating bath
and the ambient temperature.
3/4
Fig. 6.6: Optimal condensation area of a condenser