6 | Operation
BÜCHI Labortechnik AG
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Operation Manual Rotavapor® R-300
If the condensation is below 3/4 of the condenser:
u
Increase the vacuum.
ð
That will lower the boiling point and more vapor will enter the condenser.
u
In applications where no vacuum is applied, raise the temperature of the heating
bath if necessary.
ð
That will cause more solvent to evaporate.
If the condensation is above 3/4 of the condenser:
u
Decrease the vacuum.
ð
That will raise the boiling point and less vapor will enter the condenser.
u
In applications where no vacuum is applied, lower the temperature of the heating
bath.
ð
That will cause less solvent to evaporate.
6.2.5
Adding solvent during distillation
Precondition:
R
A vacuum pump is connected and running.
R
A backfeed tube leading from the glass stopcock to the evaporating flask is fitted.
1
2
Fig. 41: Cooling condenser with glass stopcock and backfeed tube
1
Glass stopcock
2
Backfeed tube
u
Connect a backfeed tube (2) for the solvent to the glass stopcock (1) and hold it in
the solvent.
u
Turn the glass stopcock until the handle is pointing downwards.
ð
Solvent is drawn into the evaporating flask by the vacuum.
u
Make sure that there is not more than 3 kg of solvent in the evaporating flask and
that the evaporating flask is not overfilled.
u
Make sure that there is sufficient space for the condensate in the receiving flask.
u
Close the glass stopcock.
