| If the goal is to distill volatile solvents (alcohols, hydrocarbons, ketones) or corrosive substances (e.g. acids) or media that generates huge
amounts of water vapour, then a mechanical vacuum pump (if it is not entirely teflon coated inside) is not the weapon of choice. Any scrubbers that
one might use to prevent the harmful vapours from entering the pump will fail in time by saturation, human error or mechanical failure and the
contaminants will enter the pump. It is just a question of when and not if. Once the corrosive or solvent agent is inside the pump oil, the seals and
mating surfaces will say a swift "goodbye" and the unit is scrap. I've seen it happen many times and the only solution is to use an aspirator station
that is basically indestructible by solvents or corrosive agents. Furthermore, one can use a suitable neutralising solution in the aspirator container
to take care of acid vapours or any other contaminants. |
