How can I improve the performance of my Findenser?

If your Findenser is struggling to contain all the solvent in your application, it is most likely due to one or more of the following issues.

Please carefully review the following information, and adjust your method where appropriate, in order to obtain optimal performance from your Findenser.

Too much solvent
  • If a flask is too large or over-filled, the condensation load on the Findenser could exceed its ability to cool and condense effectively. In such circumstances, Findenser may not contain the solvent.
  • Working solvent volumes should be a maximum of half the flask volume, e.g. 5 ml in a 10 ml flask, or 1 L in a 2 L flask.
  • The maximum recommended solvent and flask volume for use with each type of Findenser is:
    • Standard (full-length) Findenser: maximum flask size 2 L, with maximum solvent volume 1 L
    • Findenser Mini: maximum flask size 250 ml, with maximum solvent volume 125 ml.
Overheating or poorly regulated heating
  • There is no benefit to the chemistry in overheating the solvent as the chemistry cannot get any hotter than the solvent boiling point, no matter how high the temperature.  Overheating will simply generate more vapour, which could be beyond Findenser’s capacity to condense.
  • The hotplate or block temperature should be no more than 20°C above solvent boiling point for high boiling point solvents (>80°C), or 10°C above boiling point for lower boiling point solvents (<80°C).
  • Where an oil bath is used, the hotplate or oil bath temperature should be no more than 10°C above the boiling point of solvent for high boiling point solvents (>80°C), or no more than 5°C above boiling point for lower boiling point solvents (<80°C).
  • In all cases, extra care should be taken if the heating control is not fully calibrated, or does not have precise settings.
Inert gas flow encouraging evaporation
  • A flow of inert gas (e.g. nitrogen) through the flask can encourage evaporation and reduce performance of the Findenser.
  • If inert gas is required it should be introduced through the top joint of the Findenser, with all flask ports sealed (using a suitable bubbler to avoid build-up of pressure) and not through a flask sidearm or joint at the bottom of the Findenser. Gas flow should be kept to a minimum.
Ambient temperature too similar to solvent boiling point temperature
  • Because Findenser uses air to cool and dissipate heat, it requires the ambient air temperature (room temperature) to be significantly cooler than the boiling temperature.
  • At relatively high ambient temperatures, there may be insufficient air cooling for the heat from the Findenser fins to be effectively dissipated, which may result in Findenser not containing the solvent.
  • The performance in each case will depend on how different the ambient air temperature is from the boiling point temperature, so there should not be a problem with condensing high boiling point solvents.
  • To maximise performance, keep the lab cool if possible, and ensure there is sufficient airflow around the Findenser to enable effective heat dissipation.
Very low boiling point solvent, e.g. diethyl ether
  • Some very low boiling solvents (particularly in large volumes) are just too difficult to condense with any kind of air condenser.  In such circumstances a water-cooled condenser may be the only option.
  • Findenser can cope with smaller volumes of diethyl ether (up to 100 ml in a 250 ml flask) with a hotplate / heating block accurately controlled at no more than 5°C above boiling point.