Concentric Pot/Reflux Still

[rad14701]

so would anyone who's built this dare to say that this design could outperform the Boka given the right dimensions?

Perhaps... Depends on the Pro's and Con's... If you can't wind a condenser coil but can solder, well... Pretty easy to add a coupling and a concentric above the Bokakob slant plates...

[bluenose]

Any thoughts on how one that was 1" x 1.5" x 2" might perform if it was sitting on a 2" x 30" packed column?

[rad14701]

Any thoughts on how one that was 1" x 1.5" x 2" might perform if it was sitting on a 2" x 30" packed column?

It should work fine... It is essentially a dephlegmator positioned atop a packed column, providing full reflux all the time... I use my 3/4" x 1" x 1.25" atop a 1.25" packed column and get better performance than using a coiled condenser...

[Pyewacket]

I gave one of my 1" inch concentrics to a good friend of mine a few weeks ago. He is running this on a Bayou classic with a 15 gallon boiler. This little still is able to keep up (Condenser stuffed with copper scrubbers) when running very low on the 20PSI regulator. Not to get too deep into the evolution of his interest, but he did not originally think he was going to run this little still on such a high BTU burner...but, it gave this little gal a run for her money.

We were able to do a cleaning run (both vinegar and old heads), a brandy run, and a rum run all in one very VERY long day at his parent's house...god bless his folks; I guess, even after 20+ year...we continue to give them a bit of grief (heck they love us). We ran the burner about as low as we could to get a twisted stream... WE HAD A BLAST... we ran the condenser off into his parent's pool...enjoyed a cold day in Norther California. What a great little still....

He is a very intelligent fella, and with the experience over the weekend, he decided to run this gal doing a vodka run (at his house) on a 2inch column (yep, a tiny 1inch concentric on top of a 40inchX2inch column). He struggled with some concepts at first, but he understood that he was able to get 95% with a bit of finesse. He emailed me excited!!!:

I ran my 12 gallons of plain old sugar wash last night and pulled eight jars.

500ml 88%

300ml 89%

300ml 95%

300ml 95%

300ml 95%

300ml 95%

300ml 95%

300ml 95%

Around the 3rd bottle I finally got it tuned to 171.5 degrees at the head and started getting 95% in the parrot. It went really slow after that and finally gave up around 4AM and opened it up to strip what was left.

Now, it is funny that he was running lower ABV at the beginning, but he did not believe that he could achieve 95%...so he was happy with 88/89%...he started fiddling, and he had an "AH HAAA!" moment, and he was able to dial it in.

Love this still...should become a sticky

[rad14701]

Now, it is funny that he was running lower ABV at the beginning, but he did not believe that he could achieve 95%...so he was happy with 88/89%...he started fiddling, and he had an "AH HAAA!" moment, and he was able to dial it in.

Love this still...should become a sticky

Yep... It took him a while to figure out the reflux thing and then it ran like a charm... I'm sure the next run he does will go much smoother...

[Pyewacket]

I'm sure the next run he does will go much smoother...

Yes indeed. The only issue with the 1" is striping run speeds. I was worried that we weren't going to be able to turn the burner down low enough to even run this still...I am going to suggest that he switch to a 10psi regulator for a bit more control. Ultimately, he would be better off scaling it to 1.5. If I have time, I may just make one for him...won't cost much if I can pull off the no reducer design.

On a side note, I always run stripping runs for my neutrals. It impresses me a bit more that he had the still stable for as long as he did with just a sugar wash.

I wish I took a photo of the little head on top of the 2inch column...

[gatorpit]

you know this maybe it seeing as I cant wind a coil to save my life,lol I was a plumber for years and ran enough line but never had to wind a double helix condenser coil! yikes, I could have saved some money by going this route I reckon, thers a boka drawing that's similar but with a jacketed coil instead of a sleeve with an insert inside the coil forcing the vapor up around it, seems like an easier coil to wind? how about if the head was was a 2"running through a 3" jacket with a with a 3/4 coldfinger running down the whole business (as per pyewacket) but with the condensate coming straight off the 2" with the cold finger insert(surrounded with packing?) into a double plates take off system just below the head assembly in a separate collar? does this make sense , I have it drawn up but can't get it into the computer at the moment but seems viable?

[rad14701]

I honestly don't think you'd even need a coldfinger... These concentrics are far more efficient than I ever anticipated... I haven't even run my bigger original one in months because the shorter one is so efficient, with or without some structured packing in the top 1/3 - 1/2...

[multipazz]

I have been looking at this design for over a week now

I have been thinking of adding an additional jacket to the design

as i see it, this would serve 2 purposes

first both the inlet and outlet would be at the top ( running counter flow )

second I can have multiple outlets from the inner jacket
I am thinking 4 holes around the colum
this would serve to more evenly balance the flow of water
around the hot section

from what I have read I don't think the condenser requires the additional jacket
but it may also allow a further small reduction in overall length
making an ultra compact condenser

my thoughts are
.75 (22mm) throat
1" (28mm) chamber
1.25 (35mm) primary jacket
1.5 (42mm) secondary

the only down side I can see would be if the return path
taking hot water and starts heating the primary jacket
this could be counter productive

I guess I would need to know the temperature of the outlet water
to know if this could be an issue.

any thoughts on this would be appreciated

[rad14701]

multipazz, there's really no need to over-complicate this simple design... Trust me, it works perfectly just the way it is...

I just did a run yesterday with the second concentric I've discussed in this topic and it didn't even work up a sweat even with the stove burner cranked up all the way during tails collection... And the coolant flow rate was barely 1 liter per minute, if that... And with SS scrubber in the top 1/3 and only 6 inches of SS packed column I was taking off spirits at 186 proof all the way into the tails... From a 3.5 gallon boiler charge of wash and feints I ended up with 1 gallon of 100 proof neutral and 1.5 quarts of feints for future recycling...

The configuration used was my small scale LM still head build using a 4 gallon boiler and a concentric reflux condenser in place of a wound condenser...

[multipazz]

thanks rad

in my heart, I already knew, you are right

KISS (keep it simple stupid) as they say

more components = more chance of something going wrong

I did think it would look nice with the extra stage of concentric pipe
and I doubt you would want or need any further reduction in length
not like you will ever need to carry it in your pocket lol

aesthetically, it is already a beautiful design

thanks

[baron4406]

Wow guys been a while since I've been on here, haven't stilled anything since early summer- got too busy. Anyway I built an indoor,electric setup. I also wanted to build a 3" setup with corresponding still, however something just popped into my head. My 2" concentric runs like a dream, in fact its so efficient I only need the tiniest trickle of water thru it and 3/4 of the tube is ice cold. It just works. So I'm thinking since my 2" setup is so efficient why not just run it on my 3" column?? I'm gonna be running a short (like less than 30 inches) column mainly because my roof is so low in my basement. This is just to run whiskey, running the still hybrid "Rad style" is the way to go. I'm thinking my concentric condenser will have more than enough efficiency to handle a 3" column. I was looking at my 3" concentric design and I may have built it too short. Plus I'd rather just use the setup that worked so well.

Anyone think this will work?

[wolfpac]

going to make this my first build.been running a milehi for over a year with good results but ready for a little better. going with 2 inch by 32 for the column and 18 inches for the concentric.want to make a very clean neutral mostly.does it sound right?

[Doogie]

Question Rad - I have built a new modular Boka with a shotbun (12") up top.

I am thinking of modding my 2' concentric to a 1' concentric and combining that with the modular boka I am making (2' riser, 1.5' boka component, 1.5' shotgun, all 2'). Of course, I will not modify the concentric until my boka is proven, but in your knowledgeable opinion, would the concentric (packed of course) used in place of the shotgun, work well?

I am thinking of increasing the rise by .5-.75feet and shortening the concentric to 1' (I do have height restrictions)

thanks!

[rad14701]

Doogie, I think the concentric would work adequately with packing... And I'd go so far as to say that most concentrics can be shorter than we have been building them... I haven't run my longer one in months...

[Doogie]

cool - thanks - I will run with the shotgun for a while, and then shorten up the concentric after I know the backup is fine ... then report the results

[longhaul]

Rad is my hero. I had(still have) one of those 4L air cooled countertop stills. I think it was great for learning the basics and getting into the hobby of distilling. It wasn't too long I was looking at still designs trying to decide what I needed going forward. Enter Rad and his concentric still. Adding to the challenge, was the problem that I had never soldered before. I have welded, but never soldered. To start with I had acquired a 22 qt pressure cooker and a 13 qt pressure cooker. I figured I needed the bigger one for stripping runs, but didn't have the patience to save up low wines for a spirit run of that size. I built Rad's concentric, using 3/4 to 1 to 11/4. I wasn't as brave about the condenser so built it a bit longer at 12 inches. I built 2 columns, one at 6" and one at 12". The 12" is packed with copper scrubbers. The 1" in the condenser is also packed with copper scrubber. I adapted tri clover sanitary fittings to both of the boilers, and added a 11/4 tri clover fitting to the bottom of both columns. I can now swap columns between both boilers. I didn't solder the lower 3/4" fitting between the column and condenser, making it easy to separate them to swap columns. I have had no problem with vapor loss. I use the 12" for reflux runs on my saved up feints. I have gotten 87.5% hearts consistently with the reflux setup. The condenser works so well that I have trouble turning the water flow down enough. I love this set up. It is easy to clean and maintain. Many thanks to Rad for his design work.

[rad14701]

Thanks, longhaul... I can't take total credit for the idea itself, just some of the build techniques...

I just finished running mine with both column extensions but still in hybrid mode at a rate of 1oz/30ml per minute... From 13 quarts/liters of wash and feints I ended up with 4oz/125ml foreshots, 1 quart/liter of 94%/188 proof hearts, and 1 quart/liter of 80%/160 proof feints... Yes, at a take off rate of 1oz/30ml per minute... Had I run in true reflux mode the run would have taken longer and I would have had more hearts but I don't like wasting the time and gas... Coolant flow was very low and the spirits came off the still at my alcometers calibrated temperature of 60F...

[DoublyDooble]

A friend of mine who's been enjoying some of my stuff wants to get into stillin' and I'm probably going to help him build his first still. I've been itching to build another and have some plans for my own, but this little gem has been in the back of my head for a while and I re-read the entire thread yesterday to let it try to soak in a bit more.

Maybe I missed this and it was mentioned somewhere...but quick question. I know there are probably a lot of ways to fill the gaps in a reducer-less design (trying to go that route for cost savings). I'm wondering if anyone has tried, or has thoughts on, using cheap test caps with a hole drilled in the center as a solution for a reducer? If I do a 2" packed column off the boiler and go to a 1" throat that would then go into the 1" x 1.5" x 2" condenser, that 2" to 1" drop seems like a lot of space to fill without a reducer, but I was thinking of taking a 2" test cap at about $2.50 and drilling a hole, flaring the end of the 1" a bit, pulling it tight, and soldering the test cap to the 1" and then on top of the 2" column. That'd save me at least $10 just on this build and be a good technique to use in the future.

Anyone tried this?
Am I missing something?
Any reason this doesn't make sense or I shouldn't go this route?
Other reducer'less options for going from 2" to 1"?

The only thing I can think is that it might not be the sturdiest attachment and that there could be issues with the condenser sitting on top of that. I don't think it would be an issue, but just trying to think what might be negative about this option.

I may pick up some parts and give it a try just for the heck of it, see how easy/difficult it is and how solid it seems afterwards.

[Swedish Pride]

Not sure about the test caps you are referring to but I did hear about one lad who had flattened out a pipe and cut disks that he used like you describe, it was on his Liebing condenser though so the dimension were smaller.

Can't recall where I saw it, I'm sure it was in one of the construction or soldering discussions I trawled through.

What I can tell you is that it's not a very good idea (or easy to get right) to make your own reducers.

I, like you didn't want to pay for it, so I just cut loads of "V's" in the top and bottom of my 1.25 inch jacket for and clamped it in and soldered on to my 3/4 inch output pipe.

I could not get it to seal the "V's" well enough to even try to run it as was so I ended up sticking loads if silicone on it to keep the water in the leibing.
I'm left with a butt-ugly Leibing, but at least it works

[DoublyDooble]

I, like you didn't want to pay for it, so I just cut loads of "V's" in the top and bottom of my 1.25 inch jacket for and clamped it in and soldered on to my 3/4 inch output pipe.

I could not get it to seal the "V's" well enough to even try to run it as was so I ended up sticking loads if silicone on it to keep the water in the leibing.
I'm left with a butt-ugly Leibing, but at least it works

I hear ya loud and clear on this stuff. In some ways it makes no sense to try to fabricate things, at least for me. While I by no means have loads of money floating around, I do have a job where I set my own hours and I realize that from a mathematical perspective, it would be far more efficient to go work an extra 2-3 hours one evening and earn enough to buy the reducers, pipe, needle valve, etc. rather than the amount of time spent thinking about other options and trying things that may or may not work. But, that's part of the beauty of hobbies like this.

Here's what test caps look like:http://www.nationalbuildersupply.com/sh ... ApaJ8P8HAQ

They're about 80-85% LESS than a "normal" cap, for obvious reasons. They're thin and light and not designed to be left permanently. The bummer is that the big box stores like Lowes and HD don't carry them, at least not in 2" or higher, and the site I listed was going to be $10+ for shipping a $2 part. No thanks. Then today I had to run an errand about an hour north of here and on the way passed a plumbing/heating supply warehouse. Decided to just pop in. Sure enough, grabbed a couple of 2" and 3" for cheap. I think they might just work.

I have to decide what size I'm going to go with. I got a bunch of pipe for fairly cheap and have been trying to decide what still to build next http://homedistiller.org/forum/viewtopi ... 17&t=53466, and like I mentioned, I got turned on to this as a condenser to build for a buddy who's wants to get into this hobby and is going to be best setup with a 5gal gas stovetop still, and since Rad has had so much success in that setup, I thought this was perfect. But now that I've been thinking, I think I might want to build this for myself as a trial run, and make it large enough that if I put it on a 2" or 3" column it will handle everything. Then I can decide what size to build for my buddy when he comes and visits.

Rad...or anybody...thoughts on what size this should be based on other factors in the setup? If I build this for myself, I'll probably want to put it on a 3" column coming off my keg, I have a 4500w internal electric element. I'm just wondering if going from 3" to 1" in the throat is too drastic? Or how long/tall the condenser needs to be in that configuration?

[rad14701]

Rad...or anybody...thoughts on what size this should be based on other factors in the setup? If I build this for myself, I'll probably want to put it on a 3" column coming off my keg, I have a 4500w internal electric element. I'm just wondering if going from 3" to 1" in the throat is too drastic? Or how long/tall the condenser needs to be in that configuration?

I'd consider 1.25" the minimum for a throat on a 3" column... But that being a less popular size you might need to go to 1.5" unless you make your own reducers...

[DoublyDooble]

I'd consider 1.25" the minimum for a throat on a 3" column... But that being a less popular size you might need to go to 1.5" unless you make your own reducers...

The way I see it if I go 1.25" throat, then the other two layers could be 1.5" and 2" outer diameter. If I go 1.5" throat, the only thing that makes sense is 2" and 3" outer. I have plenty of 2" and 3" pipe...but I'll definitely be thinking about making my own reducers, b/c at those diameters, cost would add up pretty quickly.

This coming week I'm going to try to fool around with those test caps I got and see how feasible it is to use those as a reducer. If it works, they're dirt cheap (about $2.50 for the 3" and less than $2 for the 2"). Great thing is that if they work, you can create whatever size hole you need in the center, so doing 1.25" would be no issue. I'll take pics when I do this and post...for better or worse.

[ben stiller]

I noticed that some of the builds have the collection cup slide over the outside of the condenser column while others slide
Up inside the inner part of the condenser. Is there an advantage to one style over the other? My thought is that the external
Style has a larger cup therefore the center tube does not have to extend into the condenser as much to have the proper
Amount of collection volume. Does that make it better?

[still_stirrin]

DD,

I too have a concentric reflux condenser. Its a great design, BtW.

My column is 2" and it reduces to 1" at the condenser (4:1 reflux ratio minimum). The liquid cup is outside of the 1", in a 1-1/2" shell. The condenser water jacket is outside of that with a 2" outer shell. The condenser section is 14" long and can easily knock down vapor with up to 4.5kW power, maybe even more. I do use a SS scrubbie at the top of the condenser just to ensure the vapor fully collapses tho.

The great thing about the concentric is that it uses the pressure drop in the orifice (narrow section) to help with the thermal transfer whe the vapor velocity slows down once inside the condenser section. An excellant example of good thermodynamics design (thanks Rad).

After usung a concentric, you won't want to twist a coil ever again.
ss

[DoublyDooble]

My column is 2" and it reduces to 1" at the condenser (4:1 reflux ratio minimum). The liquid cup is outside of the 1", in a 1-1/2" shell. The condenser water jacket is outside of that with a 2" outer shell. The condenser section is 14" long and can easily knock down vapor with up to 4.5kW power, maybe even more. I do use a SS scrubbie at the top of the condenser just to ensure the vapor fully collapses tho.

These are the dimensions for what I think I'm going to build for my buddy and recommend he use a 2" column, even if it's coming off a big ol' pot on his stove. That way when he gets addicted and wants to move up to a still, he can plop it on a larger 2" column...although it seems like 14" is fairly long, and for someone starting on stove top, may cause clearance issues. I need to read this whole thread again and hear some more input from guys that have been experimenting with varying lengths.

After usung a concentric, you won't want to twist a coil ever again.
ss

I already don't want to twist a coil. I ruined so much copper twisting the first one. I finally froze it and had success doing it that way, but it ain't pretty, and I've been dreading that part of my next build. This might just solve the problem.

Regardless of what I build next for myself, I wanna build on of these condensers just for the fun of it.

[Hound Dog]

The test caps I have seen are very very thin. After all they are just meant for temporary plumbing testing. I think you will find them too thin to be useful. Just get the end of your pipe glowing red hot to anneal it and gently tap your way around gradually rolling the lip in. Once the copper is properly annealed it's hard to be gentle enough, just tap a little at a time.

[rad14701]

There are two different concentric designs in this topic... One incorporates an integral collection area while the other is merely a straight through stand-alone concentric condenser... I primarily use the stand-alone unit because it can be used in several different configurations... I can use it with my original two reducer LM head or could just as easily use it for CM or LM column configurations... I also plan or trying a dual slant plate (aka Bokakob) head...

[Kegg_jam]

Ok, i have a question about the operation / science of the concentric design.

My concentric is of the double reducer type. I've been running it with a temp probe stuck a couple inches into the loose packing at the top just so that i can monitor the amount of cooling needed to knock down all the vapors and make adjustments accordingly.

what i have experienced seems counter intuitive to me. as the temperature in the boiler is going up and towards the tail end of the run my temperature at the top of the concentric is actually going down.

at first i thought that maybe i had some air trapped in the concentric and it had worked its way out and was operating more efficiently. I have a needle valve on the output of the cooling line so as to keep some back pressure in the cooling system and maintain the water level in the condenser. the exit line is also routed up and above the inlet.

so i was wondering if anybody else would want to give measuring the temp at the head of the concentric a try and compare notes...?

I have a couple of ideas about it but wanted to know if anyone else experienced the same phenomena.

Thanks,

J

[rad14701]

Kegg_jam, I have never measured the temperature in the reflux condenser section but have noticed the progressively cooler top... My theory on this is that the cooler temperature is due to there being less alcohol and more water in the vapor and the mix doesn't rise as far up into the concentric chamber before collapsing... What I experience is the vapor temperature rising while the concentric itself gets colder...

My marble filled column works so efficiently that I've decided to shut down as soon as the vapor temperature climbs to 180F in reflux mode... There have been times when I have opened the take off valve as the tails come on and run in pot still mode until 208F but the resulting tails are so rank that I don't see that practice being worth the effort... They are at least as bad in reflux mode at 180F so that will be my stop point from now on - the recommended stop temperature for reflux columns...