Do you mean you want to be able to keep running the roto while you empty the recieving flask?
Others and myself have made different mods. I’m using a 20l collection pot connected to the roto rf with a hose, so all the etho goes directly into the 20l pot. When I want to empty that I just close the valve on the roto rf and keep the roto running while I empty the pot with a pump. Then when that is empty I pull a vac with another pump on that pot and once it’s under vac I just open the valve to the roto rf and it starts dumping back into the pot. This allows me to run the roto 24/7 if I so wish.
Some one else removed the entire roto rf and put a kf connection on the condenser and hosed it to a 15 gal keg, thus being able to run 15 gal nonstop.
I have a lot of phone calls and notifications nonstop on Monday’s, general business nonsense to deal with due to the general population taking the weekend off- it’s sort of like bang overstimulation!
From time to time, this phenomenon triggers raging psychotic mental fucking breakdowns
@spdking I haven’t seen you post much in awhile and I’d like to see you on more and contributing to the forum, I figured the only way to lure you out of your hole was to speak to you in your native language.
Idk why y’all put the vac takeoff on the top of the condenser- why not takeoff vac from the bottom of the condenser or even the middle? This is the same dumb problem I see with buchi rotovaps- why aren’t you pulling the vapors past the condensing surface of the coils? The vapor path seems inefficient and weird- am I mistaken?
The first condenser is feed intake on the top section. The vapor is doing a U shape. What he is doing is using “Hot condenser tek” to travel the vapor path towards the first condenser and using his second as a cold trap/condenser.
@spdking i have a few suggestions. The intake port needs to be well sealed. any leaks will start flashing and will carry the heavier compounds with the lighter ones. Second the vapor path is very short from the flask to the condenser. This will have to be precise operating to not carry oil with the solvent. Possibly look into a buffer zone to have some reflux happening. The buchi has these
The solvent needs a section to fall back down that’s carrying any heavier compounds.
Also a support brace for the condenser coils. Having them free dangle could cause some accidents. This applies to non discharge pump application where the metal bands need to be unstrapped.
I use to operate a buchi 220-pro and i continually fed instead of batch feeding. These are issues i see could happen.
How about a small receiving flask below the liquid-vapor separator (bump trap)? It’s counterproductive to send condensed solvent back to the boiling flask.
If you’re talking about the picture i posted than no you wouldn’t want a flask under that. You will have an impure recovery.
Your solvent is heading upwards. What this is creating a reflux. When your solvent is vaporizing from the water bath flask sometimes heavier compounds(oil,impurities, etc) are attatched to the lighter compounds(solvent) when vaporizing. If they Are traveling upwards and to a device such as this than the lighter molecule will have to shake off the heavier molecules or the whole compound will fall down. When this happens it’s making the lighter compounds strip off the heavier ones because it’s working harder to reach the top. This is just one way to get a purer recovery and an internal one with no extra required energy from outside heat exchangers.
hey tom,
Instead of assuming what NB Oler cares about try contacting them. Their team has been SOLID AS HELL, especially compared to others in this industry. MY guess is that they are a little busy running a business and didn’t see or chose not to respond on this forum. I can attest to their work and their customer service if you contact them directly, it is my opinion that they are not deserving of being lumped in with B&W and summit…
How are you able to get so much vapor production on a 20L flask to get 80L/hr of recovery?
Aren’t you limited to the surface area, vacuum and temp you can achieve. So it’s either your delta t non existent, bath temp is really high (not typical temps), you have high vacuum. Looks like the distance to the condenser was shortened as well.
Could be a combination of a few.
Interested to see what parameters the roto is ran at to get 80L/hr. @spdking
Surface area is dependent on roto speed. Higher the speed = more surface area. Key word is “feeding” not batch. He is operating the roto off of only two process variables. controlling vacuum and feed rate. This is how continual feed rotos are ran. Minus feed rate for batch application.
Before you spend a small fortune on a duel condenser rotovap remember you can use a couple 50’ stainless steel coils to achieve the same affect for about 400 bucks. Put them inline after the roto condenser, one in ice water and the second in dry ice acetone slurry leading to a cold trap. Use as big of a collection flask as you can on your cold trap or you’ll be stopping constantly
In a pinch we’ve partially submerged the inlet line into the hot water bath for the boiling flask. Not super efficient, and you have to make sure the boiling flask doesn’t contact that line, but it kind of works
Yeah that’s pretty minimal for surface area contact. That’s why 2 50’ stainless coils are more ideal. It’s a lot more space for it to travel to warm it up. In the past I’ve used silicone tubing coiled up (about 25 ft) for both hot injection and cooling vapor before a cold trap and after a condenser and I find the stainless is way better. It transfers heat a lot more effeciently.
I was honestly how surprised a difference it makes. The first time I tried it was about 4 years ago on a short path system I was using to recover ethanol in a pinch. I set up 25 ft of silicone hose in a coil inside of ice water with a pond pump after the spd and before the cold trap and it almost doubled the output. Dry ice slurry on cold trap for final stage of cooling. Used way less dry ice on the cold trap as well since the vapor was already mostly cooled and ultimately it all lead to way deeper vacuum levels.
