Vacuum Still

Many like to post about a first successful ferment (or first all grain mash), or first still built/bought or first good run of the still. Tell us about all of these great times here.
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Bazil
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Vacuum Still

Post by Bazil »

I used mostly PVC on my setup to save money, after all my system should never get over melting point of PVC while in operation. I use a Plexiglas lid (and a giant rubber o-ring) so I can see into the pot which is held in place by nothing but the weight of the atmosphere. That way if something went wrong and the pressure went up the whole still would fall apart the second there was a positive pressure instead of exploding. I'm not using my still for alcohol, at the moment I'm just running large volumes of water to concentrate essential oils from.

The pot itself (at least for now) is a small painter's pressure vessel. The whole still sits on a small propane burner used for camping stoves. The low price of the PVC allows my to have a large column and condenser. Although I do use a copper condenser coil. I tested out using thin plastic tubing because it was so cheap but the condenser was at least three orders of magnitude less efficient. Also where ever possible I use screw together parts (including the pvc pipe) to make experimenting and swapping parts fast and easy. Though this makes leaks more likely they are easier to trouble shoot and fix since all I need to do most of the time is use more telfon tape.

To get the fluid I'm going to distill into the system I have a feed line with a valve. That way as the chamber starts to get low I can let more in by opening the valve. As long as there isn't any air in the line that doesn't really increase the pressure much. Just a bit from degassing which can be pulled out by running the pump for a few seconds. It has two chambers, the one that's heated and one for collecting the distillate. I have separated vacuum lines and valves for each chamber so once the chamber I use to collects the distillate gets full I can close the vacuum and condenser lines, break the vacuum on just that chamber, empty it, put it back and then open just open the vacuum line to that chamber so I can pull a vacuum before opening the line to the condenser.

It functions quite well now (though it was a long road), but requires me to baby sit it the whole time it's running because it doesn't have enough fail safes. I plan to add a vacuum releaser to it which will take all the labor out of removing the distillate. Also I need some valves, solenoids and thermostats so I don't have to be adjusting it by hand all the time and making sure the thing doesn't run empty, which would be catastrophic. I also intend to add a fridge and a pump to cool the condenser, right now I just run cold tap water (about 45F) through it, but the condensing power isn't that high since I'm often running it at very low temps of 100F or less.

So far I've managed to get the pressure down far enough to boil water at 60F, which is about half an inch of mercury above an absolute vacuum. This was a bit of an accident though since I was trying to pull ice out of the feed line. I don't usually run it at that pressure. All in all it pretty fun to run the thing, and very satisfying to see a moderately complex machine I designed and built actually function. I'll come back later to add pics since I don't have any of it in it's current configuration. Anyone have any feed back or suggestions?
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Re: Vacuum Still

Post by Prairiepiss »

Built it out of PVC and plexiglass. Really? Is this a joke? Have you read the rules we live by?
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Re: Vacuum Still

Post by Bazil »

Um, nope and nope... The PVC and plexiglass aren't exposed to high temps or pressures. In fact while it's boiling away I can set it up so the pot is cool to the touch. I only went metal where I absolutely had too. Basically the part that is directly exposed to flame, the condenser coil, and various fittings which needed to be reliable and leak free.

The plastics are generally resistant to chemical attack at the temps and concentrations they would experience even if I was using it to distill ethanol, which I'm not.
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Re: Vacuum Still

Post by BIGBIRD123 »

Are you freaking kidding? Dude, you need to do some serious reading...like right here...

http://homedistiller.org/forum/viewforum.php?f=46

...and especially here...

http://homedistiller.org/forum/viewtopi ... =35&t=5090
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Re: Vacuum Still

Post by bellybuster »

This has got to be a joke.
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Re: Vacuum Still

Post by Prairiepiss »

Like I said have you read the rules we live by?

8. These forums take a very strong negative view on the usage of plastics and synthetics in distilling. It simply is not safe to use in any area of hobby distilling (however HPDE buckets are acceptable for fermentation.) There simply are too many types of plastics and lack of reliable information about plastics, for us to reliably advocate their use anywhere in the distillation apparatus. Also, from past posting history, this topic seems to quickly boil down into an almost religious flame war. Thus we simply will not put up with it, and posts about any form of plastic use will be edited, deleted or locked. There is a forum for proven info for or against any material (material/safety.)
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Re: Vacuum Still

Post by Bazil »

My set up is perfectly safe. I'm a scientist and have done vacuum distillation in the laboratory before. I also studied the materials carefully before choosing. Although considering I was unaware that this forum prohibits the discussion of stills that use plastics as a blanket policy not taking the details into account. Further more I'm not going to switch my materials just so I can discuss it on here. So I guess this will be my last post.
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Re: Vacuum Still

Post by Prairiepiss »

My set up is perfectly safe.
This would be your opinion. Research I have done shows PVC and plexiglass is not safe materials for a still. And you shouldn't want to change it to discuss it. You should want to change it for safety reasons. But obviously you know better then those of us that are not scientists.
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Re: Vacuum Still

Post by NcGunny »

I really hope you are joking about this or just a troll which I assume from ur posts the second is more likely. Every guy I ever knew that was in a scientific field had as much equipment at home as he did in his lab. And if you are serious...really stop watching Youtube videos. Half the distillation videos on there are accidents waiting to happen...read..ask questions...learn from others mistakes before something goes Ka..Bamm!!!
Is your life worth.."Better fix that next time"????
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Re: Vacuum Still

Post by Bazil »

Listen I understand where you guys are coming from Ethanol+plastic+high temps+confined space=bad. Under normal conditions a still is a bad place to have plastic. Ethanol is capable of attacking and weakening PVC and many other plastics at elevated temps and pressures. Stills generally have both of those, but I think what you guys are missing is only one of those four things I listed that my still actually has is the plastic. Remember as I stated earlier I'm not distilling ethanol or other flammable/explosive products. Also keep in mind this is also a vacuum still that is held together by external atmospheric pressure. A positive pressure inside the still is not possible.

You know people with as much equipment in their homes as their lab? They were either really rich or the lab was really poor. Then again you could be talking about different kinds of labs than I'm familiar with since my area of study was biology and chemistry. My current profession is in equipment for automating certain lab tests and no I've never watched any YouTube video on distillation. I can see why they made rule #8. People get hot under the collar when someone uses the "P word" around here. I'm not a troll, I just wanted thoughtful feedback not negativity. But I feel that either I didn't explain my setup to you guys well or you guys simply don't understand what I'm trying to say. I should draw up a design so you can see exactly what I'm trying to describe.
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Re: Vacuum Still

Post by Prairiepiss »

Alcohol essential oils. What's the difference? I've researched essential oils. And they feel the same about plastics as we do for alcohol. Stainless and copper are also preferred for essential oils. So your choice of materials makes no since.

I hope the essential oils you are making with it. Are for fragrance. And not medicinal. Even aroma therapy wants the purest oils.

So maybe you should explain to us what it is you are trying to make with this plastic still? Because I for one can't figure it out.
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Re: Vacuum Still

Post by bearriver »

Prairiepiss wrote: I hope the essential oils you are making with it. Are for fragrance. And not medicinal.
This exactly. Rules are rules and they exist because people are retarded. Someone is likely to read a thread like this and stop at "pvc is safe" then apply it no some twisted fantasy. It sure wouldn't be the first time.

To the op: You mentioned that you aren't going to switch your materials to post here. Now everything your going to get here is going to be "negative" if that is what you want to call it. You know the rules, I think you can quit wasting everyone's time and find another website to post this at.
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Re: Vacuum Still

Post by Bazil »

Ok, I understand your position completely. Like I mentioned I choose the materials I did for the ease of changing things at low cost on the fly to improve the design. If I ever decide to build one as an appliance rather than for conducting experiments I'll probably go with metal for the reliability and durability. In that case I'll come back and share it with you guys.
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Re: Vacuum Still

Post by Prairiepiss »

Why would you build something to experiment with. That will not make a safe usable product to test?
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Re: Vacuum Still

Post by Bazil »

It does make a safe usable product for most of what I'm doing. The water that is being distilled out my wife is using in our humidifier for instance. The nutrient rich precipitate I collected I used for plant food. Also my goal isn't to distill out certain products for human consumption. It's more to remove water or other unwanted things from the solution without destroying other chemicals that are usually degraded when heated. The container that these substances are in is one of the metal parts. It's what is left behind that I want for human consumption. Currently my goal is to concentrate flavor from plant material without altering them. I don't want to go into detail about what plant and why since I'm trying to create a novel product that no one else has and I don't want someone who has more money and resources than me to steal my idea and beat me to the punch.

I realize this forum is mostly geared towards ethanol production, but you guys have a lot of experience with still building and running and I was looking for feedback. Technically if I didn't care how hot things got I'd just throw it all in a pot and boil it, no still needed.

Also even if I did use it to still out products, it's fine for experimentation. The products wouldn't need to be consumable for the experiment. It would be more for rapid prototyping of still design. At the moment it only costs me between 5 and 20 dollars to make a major change to the design. Once the design was optimized for production of a particular product, I would drop the money for the metal parts, which cost 10 times the price. Most of you guys know exactly what you want to get out so you just go for a tried and true design, you don't have to prototype.
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