7. FAQ's and Knowledgebase / Rotary Evaporators

Can I add further liquid to a rotary evaporator during operation?

Q: Can I add further liquid into a rotary evaporator while it is already running?

A: Yes – this is possible with certain models of rotary evaporator, such as the KNF RC600 model, by using the refilling valve accessory.

RC600 rotary evaporator
The RC600 rotary evaporator by KNF

It is possible to add further liquid or solvent into the RC600 rotary evaporator even when the unit is in use and under vacuum.

The refilling valve accessory must be installed (sold as a separate accessory, reference 300639) this is labelled as part 5 in the diagram below;

RC600 Rotary Evaporator Parts
RC600 Rotary Evaporator parts diagram

Additional liquid may then be added to the evaporation flask (labelled 13 in the diagram above)

“Using the refilling valve, the evaporation flask may be refilled under vacuum during operation as follows;

  1. Connect the refilling valve to the additional medium
  2. Open the refilling valve

The additional medium will be drawn into the evaporation flask”


See further information on the RC600 rotary evaporator here, or contact us with any questions;