7
BÜCHI
Rotavapor
R-187EL
3 Function
A vacuum rotary evaporator is used to carry out single-stage
distillations at high speed and low stress. The process is
based on the evaporation and condensation of solvents using
a rotating evaporating flask.
The operation is made under vacuum to protect the product
from stress and improve efficiency.
The vacuum seal of the rotation unit is tight in the low pressure
range. If any harmful solvents are evaporated, a minimal low
pressure is needed to guarantee a secure closeness
3.1 Functional principle
The vacuum rotary evaporator is used to carry out single-
stage distillations at high speed and low stress. The process
is based on the evaporation and condensation of solvents
using a rotating evaporating flask. The distillation can be
performed under vacuum or at atmospheric pressure.
Evaporation zone
The solvent in the evaporating flask is heated by the hot
bath. The rotating evaporating flask generates intensive
turbulence in the flask and forms a thin film of solvent on
the inside surface of the flask. This combination of
turbulence and film prevents local overheating and guaran-
tees a high rate of distillation.
Rotary drive
The drive unit ensures uniform rotation of the evaporating
flask.
Cooling zone
The solvent vapor flows at high speed into the condenser.
This is where the solvent vapor´s energy is transferred to
the cooling medium (e.g. water) - the solvent condenses.
Receiving flask
The receiving flask is used to collect the condensate.
Vacuum connection
The solvent´s boiling point temperature can be lowered by
reducing the system pressure. This results in lower ther-
mal loading and less stress on the product.
The efficiency of the evaporator is influenced by the pressure
of distillation (vacuum), the temperature of the heating bath,
the speed of rotation and the size of the evaporating flask.
For details of how to select the optimum distillation conditions,
see Chapter 5.3, Selecting the conditions of distillation.
Figure 3: Functional principle of the R-187
3 Function
