10
Rotavapor
R-220 EX
3 Function
3 Function
Fig. 3.1: Principle of operation of the R-220 EX
A vacuum rotary evaporator is used for quick single-stage
distillations that treat the product gently. The process is
based on the evaporation and condensation of solvents in
a rotating evaporating flask.
It is possible to work under a vacuum to ensure gentler treat-
ment of the product and increase productive output.
Distillation may be done either under a vacuum or at atmos-
pheric pressure.
A secure closeness is guaranteed in the low pressure range.
3.1 Principle of Operation
Evaporation Zone
The solvent in the evaporating flask is heated by the hea-
ting bath. The rotation of the evaporating flask ensures an
intensive exchange of heat and mass within the contents
of the flask, forming a thin film of solvent on the inner sur-
face of the flask. This combination of turbulence and film
prevents local overheating and ensures high distillation
speed.
Rotary Drive
The drive unit ensure the uniform rotation of the evapo-
rating flask.
Cooling Zone
The solvent vapor flows into the cooler at a high speed.
This is where the energy in the solvent vapor is transferred
to the cooling medium (e.g., water). The solvent conden-
ses.
Receiving Flask
The receiving flask is used to collect the condensate.
Vacuum Cover
The system pressure is reduced so as to lower the boiling
point of the solvent. The reduction in thermal loading that
results ensures gentle treatment of the product and offers
energetic advantages.
The pressure (vacuum) of distillation, the temperature of
the heating bath, the rotational speed, and the size of the
evapo rating flask all affect the evaporation output. Refer to
Chapter 5.5.3 for how to select the optimum conditions of
dis tillation.
