getting two 20L rotos from AI.
Going with dual condensors, dual recieving flasks, and a DLSB-50/30 chiller from USA labs. looking at either a welch 2052 or 2163. Wondering if thats overkill?
Want to push them to their absolute max.
ive seen alot of recommendations for tiny ass pumps. id rather spend the extra 2-3K and pull a couple more liters an hour if possible. Thoughts?
unlike SPD or WFE, with your rotovap it’s generally not the pump that is the choke point. it’s the chiller.
so long as you’re not looking at an aspirator based “pump”.
throwing a bigger pump on there without a bigger chiller just puts your solvent in your pump.
the DSLB-50/30 is a 50L -30 chiller so its way bigger then standard chillers. hence why im trying to max out my pump similarly.
so basically ive got the big chiller, now how big could i theoretically go on a pump before im pulling ethanol into my pump? plus i will have a cold trap in front of the pump so i know roughly how hard i can rock it before i start pullin ethanol through.
You can get. $300 Chinese pump that uses circulating water. I use this for my 20l. Like said above, you don’t need a massive pump for rotovap. Across international tries to over sell you on auxiliary equipment. I’ll post a link when I’m at my PC. (Unless someone can beat me to it. I’m sure other people have this pump.)
Also wanted to add you can get the same rotovap as AI for half the price via alibaba. I think touch science may have them. I also recommend YChem, or I can hook you up with my girl who knows how to cheat on import tax 
It’s more about UL listing. Nothing China is getting UL listed or I’d go cheaper
I get that. I’m not trying to go for cheap. I’m trying to go for the ABSOLUTE most ethanol this 20L can pull off a second. Not the cheapest workable roto
Im getting the same setup ( two 20L from AI with dual condensers and receiving flasks ) as you are next month and I wondered the same question. Are you getting the vacuum regulator as well?
You have used the word “big” What are you referring to? You chiller is “big” because it has a large reservoir? That means the liquid won’t heat up as fast working against the heat of your evaporation. What makes a pump “big”? Sucking power? Vac depth?
The point of the vacuum is to lower the boiling point of the etoh. The deeper the vacuum, the lower the boiling point. The lower the boiling point the more terpene/cannabanoid retention. I’m guessing you’re making CBD products, so you don’t care about terps. You’re not going to boil off your cannabanoids. High CFM’s will vac the system faster, then perhaps pull vapor past the condensers into your pump.
What do you want to be “big” about your pump?
This is the pump I was referring to:
http://www.kdinstrument.com/products/Electric-Water-circulating-pump.html
okay i get what your sayin now. So basically once we have enough vac to lower it to the desired boiling point, additional vac is essentially pointless?
essentially i want to run it as hot as possible without losing any cannabanoid profile in order to boil off the maximum amount of ethanol per minute. so it would be more about chiller power since the vac doesnt rly play much of a roll anymore.
By big i mean large resorvoir and large amount of chilling power so the temp of resorvoir stays at a consistent temp even when its up against massive amounts of hot ETOH vapors.
so hotter i go on roto, more ETOH is boiled per minute, so the chiller must be able to not only keep up with the hotter vapors, but also more vapor in general per minute.
that make more sense? its definitely a rough way to put it, im no scientist by anymeans.
so what i want is the MAX amount of ETOH i can evaporate and recover per minute without negatively impacting my oil (dont care about terps)
You get it now
so how instead of matching BTUs of heat to BTUs of cooling i need to surpass the cooling side with like 25% more power then heating ya? or maybe even more like 40%?
May I ask how much biomass you’re extracting/day and how you’re doing it?
you’ll get more benefit from adding ping pong balls to your bath. (or an insulation dome)
I imagine The more cooling power and cooling surface area you can add the hotter you can run your bath. You will be better off adding preheat to your input as well as adding a cooler of ice to your collection flasks. There is a thread on here about a roto booster where someone put a plastic sleeve over the outside of his condenser and filled with dry ice to add to the cooling power.