I’m looking to purchase a 20 liter rotovap from usalab I’m just wondering what chiller and pump I should get to achieved maximum efficiency
matching the chiller capacity to the heater capacity is a decent start.
the energy you put in to make vapor has to be taken out to make liquid again.
ie if you’ve got 4500W of heat available, having only 200W of cooling will make for very disappointing performance. Whilst having 5000W will allow you to condense most of the vapor you can produce.
how many watts is the heat bath on your proposed purchase?
Edit: there are also terms in the maths that involve delta-T (temp differential), heat transfer fluid flow rate, and evaporator/condenser surface area…which reminds me I’m supposed to be spec’ing a pump to keep my FFE evaporating at full speed…and need to go find that math. 
http://future4200.com/search?q=ethanol+math
http://future4200.com/search?q=Chiller+calc
2 Likes
It’s 8kw heating power
A must in a Roto is a dual recovery flask for uninterrupted process.
Also upgrade chiller. A 10l upgraded chiller outputs more an hour than 20 l regular one, a 20liter upgraded chiller better than 50l regular. It’s all a matter of the liters per hour you can distill and the chiller is key.
A double condenser is an awesome upgrade if you can
A vacumm regulator is very nice but not essential for hi volume operation
2 Likes
https://www.usalabequipment.com/usa-lab-20l-rotary-evaporator-turnkey-setup-rotovap-re-1020
I’m seeing 17000BtU of heating and 4000 to 13500 BtU of cooling in their turn key setup.
so I suggest upgrading from the DSLB 30/30 to the DSLB 50/30 which does 12000 to 25500 BtU
https://www.usalabequipment.com/usa-lab-30-c-50l-recirculating-chiller-dlsb-50-30-30l-min/
2 Likes
Oh sorry I’ve decided to get a re-5003
What’s the best upgraded chiller for that?
same logic…
match hot to cold.
and then add a little more cold for good measure.
8kw is about 27kBtU
so bigger than the DSLB 50/30 would be advised.
2 Likes
What would you recommend for pump?
have you looked at Best value pump for a 5L roto
a diaphragm pump or water aspirator (like the one spec’d by USA Labs) is most appropriate for a rotovap, because chances are you’re going to get solvent in it. don’t recall which welch pump we were running on our 50L setups, and have no idea (doubt) an aspirator will keep up.
1 Like
In that thread, it basically says the aspirator can’t keep up. I would also be interested in pumps that can power a 20L. As I will be adding 2 of those once I reach my scale with the 2 5L’s.
1 Like
If you go with a water aspirator pump, keep in mind the motor heats the water up and you have to keep adding frozen bottle of water or the lil one I use is hooked up to a lytron water chiller which keeps my water at 7c the whole time. The hotter the water the less vac it will pull, this is just my experience I usually use diaphragm but I use the water one on the roto that I decarb in so the water absorbs all the nasty smell so I don’t have to run a cold trap otherwise it smells horrible.
4 Likes
Grab a Welch 2047B-01
1 Like
Sure. That doesn’t mean it can’t be done if one is determined. A fast water pump and a chiller and a big Venturi.
Makes great sense if you’ve got unlimited cold water. Even if you have to pressurize it I imagine
What would be an appropriate vacuum level to use with a 50l rotovap and diaphragm pump?
I have just ordered a vacuum regulator and wondering what I should have to set to.
I’ve experienced this first hand with my 5l rotovap and water aspirator. This is why I’ve decided to go with a YH-700 diaphragm pump paired with the RE-5003 50l rotovap I ordered from lanphan.
Hello,
If you use re-5003, you could use 50L chiller. and also need to make sure the lowest temp. then we could make sure accurate model.
if you want to know which model for chiller, pls tell me.
I use a lytron water chiller for my water aspirator pump, keeps it at a constant 35f. Tou can get them in ebay for pretty cheap. If tou so fo this route tour fonna have to fine tune the valve rhat pulls water from your pump. My pump pushes water out faster than the chiller does, so aftwr a few wet floors i got it dialed in
1 Like
What about using dry ice/icecubes to keep the water in the water aspirator down?
Ice cubes work. I used to use those frozen cooler insert things vs ice cubes.
8kw heating is a lot. You better get a good chiller.
Other wise the un-condense vapors will get into your vacuum pump.
Then you either change the pump oil frequently or you you may damage your expensive pump.
Did you decided which 20L rotary vap to get?
I know a 20L dual condenser unit that is working very effectively.