@Thetetraguy 20L a minute
@Speedofgreen it condenses a little bit maybe a few drops
When I pull tok deep of a vac with my welch wobl, I noticed this as well. I was/am using tap h20. I do use the waste water for my garden.
I now keep vac at -26.5hg and no more vapour into my pump.
My chiller should be fixed soon. Hopefully with much colder condenser fluid, I should be able to do +50% more volume.
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When I notice this I twist the knob to pull less vac but I notice the vapor still makes its way up.
I’ll post a video later but i dont think this should be happening
details on that motor and passthrough?
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Found my problem!!! Was the cheap ass bestvaluevacs cold trap i was running in between my rotovap and dpump
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I actually am facing the same problem as you are right now with my Lanphan RE501 and Welch diaphragm. What exactly was wrong with the cold trap?
I have the same setup, but I never use a cold trap. 48c water bath, -26.5 +/-.x, and zero vapor past the 2nd to last coil.
Which chiller do you use?
Seal. Its the cheap one from bvv. https://www.bestvaluevacs.com/1-5-gallon-cold-trap-2qt-tank-dry-ice-liquid-nitrogen.html
Lol
Tap h20 currently
My -20c is being repaired
Damn so you use tap h20 and get a gallon an hour?
Oh wow, so you were leaking at the cold trap?
Im near 1g/hr
Yes
My tap is about 50f or colder
Yeah I’m just gonna get a new one tbh. Most likely thier new stainless model. It looks a lot better. Cause I like using a cold trap with my diaphragm pump and I need one to purge out my eho.
I think I figured out the issue - my circulating fluid is isopropyl alcohol which has a low heat capacity
Going to test when I get my ethylene glycol since I’ll be running a mix in my chiller instead
Does anyone else run isopropyl or other alcohols in their chillers for their rotos?
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I’m interested in a 1L setup from hfs. They said I can put a 3L flask on it.
My question is how much is this going to recover per hour. And what type of pump can I get away with using.
And finally can I get away without a chiller?
Dry ice and a water pump maybe?
Yup! That’ll do it. Propylene glycol is going to have a much better heat capacity than any alcohol. Not quite as good as water though. I’m just using ice water right now.
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Ok so after a lot of playing around I have found that I can get a solid 25LPH recovery time on my 20L re1020 rotovap.
No preheating cool, though I have used one before-
The goal is to balance the amount of evaporative cooling - which should be a lot- with the heat of your bath, your vacuum, the temp of your feed, and the viscosity of your flask material as determined by the saturation level.
I use a brass bleed valve to control the vac level and I then tweak the temp, feed speed, and vac until it seems to be balanced and I can walk away from it for a long time and it seems to maintain itself.
I think the main thing to consider is balancing the evaporative cooling of the material of the flask with an increasing vac level until it seems to balance. Hard to explain without just showing it live- I have a vid on my insta from last night @vene.ficium
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Awesome
It’s a 100rpm 12v gear motor 3/8 D shaft. The feedthrough is a stainless steel rotary feedthrough 3/8 D shaft as well. The feedthrough is not a Ferro fluid model, it has a serviceable O ring. I have to replace the Vac grease every 3 run.
If I were to build it all over again I would definitely go Ferro fluid feedthrough.
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