Hey great project man!
Having access to fabrication/machine shops with willing operators is priceless. I have no doubt you can get one of these up and running.
I’m confused about your intentions. Are you making something to recover bulk ethanol from the post-extraction solution or something to distill cannabinoids from crude?
The main idea behind a thin/wiped film evaporator (both internal and external main condenser designs) is to minimize the residence time of thermally sensitive products. The internal condenser design (short path) is meant to allow higher vacuum ranges to get the lowest possible boiling temperature.
To recover ethanol after extraction you won’t need to use temperatures high enough to degrade the cannabinoids at a high rate so residence time in the still isn’t really a big issue. This makes it hard to justify the complication/expense of a wiped film design, either internally or externally condensed.
If you used an internal condenser design for recovering bulk ethanol you would likely overload the condenser quickly and any type of bubbling/bumping of the solution, which is common, would contaminate the clean ethanol very easily. An external condenser design would probably work as a replacement for a rotovap but isn’t really the best tool for the job and rotovaps are already relatively cheap and plentiful. Once you are at large scale you would run into the same issue as rotovaps in that you would need to use so many separate wiper units to keep up with production you would quickly want to replace them for a tube-in-shell evaporator system because it is way more efficient from multiple stand points.
If you were on a medium to large scale and needed hundreds of liters per hour recovery I would suggest attempting a falling or rising film evaporator build instead of a wiper.
If you really just need about 5 gallons per hour recovery like you mentioned, a 50L rotovap with a good solid chiller (4-5Kw @ 0C) should be able to fit the bill just fine and will probably cost less than the money you’ll spend on this project.
If your aim is to distill cannabinoids from crude I think you are headed in the right direction with the internal condenser design. I will include a couple pics of proven condenser designs you can work off of. Maybe @Future can chime in about the ferrofluid seals, I know the Skunkpharmers were using one when they almost had their Terp Trommel project up and running.
