I have been distilling for about a year I work as a Mechanical Drafter and I have the ability to draw up 3d models of still designs.
I have not built a still before. However I am keen on building a vapor management rig in my spare time over Christmas. I have a basic know-how of the principals and physics behind distilling however I am new to the world of designing and building efficient column stills.
I have drawn up models of a 2" and 3" vapor management stills, although they are only rough designs and I believe have some design errors. I will upload them shortly i was wondering if people with experience in building stills could lead me in the right direction to fixing up the designs.
I have about an hour and a half a day in which I can work on the 3d models and will continue to work on them until the plans are agreed to be error proof and of an optimum design.
Once the model is finished I plan to compile an item list and make a step by step construction method to building the stills I believe this will be of advantage to allot of the members of this site who do not have knowledge of building stills and want an up to date optimum design still.
Hi Nicks, your drawings are beautiful. The 2" looks more in proportion for home stillin needs. The 3" is HUGE; it will need a minimum boiler charge of 40L and a rocket motor to power it by my rekoning...perhaps a longer leibig will not go amiss on the 3"? The cap on the top of the column should be showing a vent hole...it's important to show it in the drawing because it must be there.
I await developments and other comments with great interest. Cheers!
The reflux condenser section in both versions is serious overkill. 250 mm is plenty for both. If you use a double coil condenser it can be shorter, about 200 mm. Even that still gives you plenty of condenser capacity.
There is nothing wrong with having the tall packing section in the 3", but past about 1500 mm of packing height you start running into seriously diminishing returns. You also start running into height problems with standard houses and buildings. Very few here run above 1500 mm or so of packing.
The tube size from the chimney drop through the Liebig is too big. For 2 or 3" VM columns you only need 13 mm (1/2") inside 19 mm (3/4").
It is better if the larger outer coolant jacket on a Liebig condenser is only the next size up from the inner vapour tube. So use 12 mm inside 19 mm, 19 mm inside 25 mm, etc.
The chimney drop on the 3" does not have to be that long. (I realise that extra length comes mostly from the extra packing height.) The 2" chimney drop length is fine.
Tomorrow i shall add vent holes to the caps on the top of both of the columns on the design.
How long should i make the liebig on the 3"?
Can i make the reflux column shorter? If so how much? I tried to stick to the 1:24 rule so the length of the column is 24 times the width + the length of the condenser is this correct?
Hi Hook thanks for your comments i will shorten the top of the column to 200mm to allow for a double coil condenser
When i get around to building my still i will purchase a condenser off you .
I will shorten the 3" packing section to 1500mm tomorrow
I will also change to liebig down to 13 mm (1/2") inside 19 mm (3/4"). I'm just wondering how long i should make them? and should the 3" one be longer than the 2"
Also I'm just wondering is the chimney drop the tube between the elbow and the liebig or is the chimney drop the total distance from the elbow to the very end of the takeoff pipe.
I will make sure the top caps on both the models are vented.
NicksExa_N13 wrote:Hi Hook thanks for your comments i will shorten the top of the column to 200mm to allow for a double coil condenser
Leave approx a 40 mm gap between the bottom of the condenser and the top of the take-off port.
When i get around to building my still i will purchase a condenser off you .
I will shorten the 3" packing section to 1500mm tomorrow
I will also change to liebig down to 13 mm (1/2") inside 19 mm (3/4"). I'm just wondering how long i should make them? and should the 3" one be longer than the 2"
500 mm is enough for the length of the coolant jacket. My Liebig is 1/2 inside 3/4", times 500 mm long, and I also use it for stripping runs at 2400 w and it handles that easily. The output rate of a reflux column is not high anyway.
Also I'm just wondering is the chimney drop the tube between the elbow and the liebig or is the chimney drop the total distance from the elbow to the very end of the takeoff pipe.
I would think it is to the top of the Lieibg. As the output rate of a reflux column is not high, so the vapour will be condensed in the first 2 inches or so of the Liebig.
I will make sure the top caps on both the models are vented.
Nicks, I think the leibig on the 3" needs to cope with a higher output than the 2", mainly because the 3" will handle a bigger heat input. (column diameter = speed = heat input).
Re the chimney drop, I believe this is the distance between the bottom of the reflux condenser and the vapor take-off port. The vapors do not rise on their own, they are pushed up the column from below, thus the vapors have weight. The greater the pile of vapors above the take-off port, the more vapors will want to flow down the take-off port.
For the same reason, (vapors have weight), vapors dropping down the pipe to the leibig will cause suction at the take-off port.
This remains a topic under experiment. Some lengths and diameters may be better than others, but the gate valve will find the balance whatever!
Another design element you may want to consider: You really don't need to use the large, (read expensive), valves. The valve can be placed after the elbow and reducer. In this position a 1" or even 3/4" valve would be more than enough.
It is the very things that we think we know, that keep us from learning what we should know.
Valved Reflux, 3"x54" Bok 'mini', 2 liebig based pots and the 'Blockhead' 60K btu propane heat
Above is the latest on the 3" vm design i have changed the tee into a reducing tee that reduces from 3" down to 1" i have also changed the liebig down to 3/8" copper running through 3'4" copper pipe.
In the drawing 1/2" inside 3/4" would not fit.
What do you peoples think of the design any comments on further design improvement is much appreciated
Btw you have to click on the thumbnail to enlarge the drawing of the still.
Okie dokes, sorry i must have made an error of judgment when drawing the liebig condenser when the model is in wire-frame mode there is an abundance of lines and things can become quite confusing I will change it back to 1/2" inside 3/4"
I have thought of two possible locations for the reducer from 2" down to 3/4" these being between the gate valve and the elbow or after the elbow.?
I'm assuming the reducer from 3/4 inch down to 1/2 inch on the take off line should be positioned just before the liebig condenser?
I'm also wondering would the use of a centring ring make this vm design more efficient?
Thanks for the comments on the design please keep them coming as in the end i believe the finished model and plans will be a benefit to myself and many forum members.
NicksExa_N13 wrote:Okie dokes, sorry i must have made an error of judgment when drawing the liebig condenser when the model is in wire-frame mode there is an abundance of lines and things can become quite confusing I will change it back to 1/2" inside 3/4"
I have thought of two possible locations for the reducer from 2" down to 3/4" these being between the gate valve and the elbow or after the elbow.?
Either way works.
You have a 2" gate valve? You can reduce between the take-off port and the valve, which means you only need a 3/4 valve, which saves a fair bit of cash.
I'm assuming the reducer from 3/4 inch down to 1/2 inch on the take off line should be positioned just before the liebig condenser?
I started with 3/4" to the top of the Liebig, than swapped to 1/2". Doesn't seem to make any difference.
I'm also wondering would the use of a centring ring make this vm design more efficient?
Yes, use some kind of reflux centring set-up.
Thanks for the comments on the design please keep them coming as in the end i believe the finished model and plans will be a benefit to myself and many forum members.
I think it will. A good drawing is worth a thousand words.
First post, and sorry in advance for the dumb question, but this VM still looks like an easy build, so why are there so many CM stills on the market and apparently in use(judging from the number of pictures of different designs I've seen)?
I've only played around with a pot still of limited size and was thinking of going with a Mile High 3" "Torpedo Reflux" tower because of apparent build quality and claimed speed and quality of output, but after reading many posts it seems that CM designs are not viewed favorably. Since the VM design in this post looks to be buildable from off the shelf parts I'm going that route unless someone has a better idea that they'd care to offer. Is there something I'm missing? Is there a link that I've missed to a more proven VM still?
Lastly, what kind of vent are we talking about in the top of the column? An open vent hole, a completely open stack, a pressure valve of some sort? Thanks in advance for any and all help.
BBQKing wrote:First post, and sorry in advance for the dumb question, but this VM still looks like an easy build, so why are there so many CM stills on the market and apparently in use(judging from the number of pictures of different designs I've seen)?
Not sure. Maybe it is because the commercial guys have not caught up with design development. Or maybe there are copyright issues with other designs. But CM is definitely inferior to LM and VM for making neutral.
I've only played around with a pot still of limited size and was thinking of going with a Mile High 3" "Torpedo Reflux" tower because of apparent build quality and claimed speed and quality of output, but after reading many posts it seems that CM designs are not viewed favorably. Since the VM design in this post looks to be buildable from off the shelf parts I'm going that route unless someone has a better idea that they'd care to offer. Is there something I'm missing? Is there a link that I've missed to a more proven VM still?
No, that is about as good as a basic VM column gets, with the small changes I suggested.
Lastly, what kind of vent are we talking about in the top of the column? An open vent hole, a completely open stack, a pressure valve of some sort? Thanks in advance for any and all help.
Any of those will do. I would not use a pressure relief valve unless it is a very reliable one. Simply leaving the top of the column open is fine. No need to make it any more complicated than necessary. If your reflux condenser is working properly there will be no vapours escaping.
Thank you for the reply. I've been living on this forum for the past 2 weeks and I'm starting to have brief moments of clarity every few hours as the absorbed information filters itself in my brain and starts to make sense. This is really interesting stuff.
Take your time. A little patience and research & reading, and the occasional question at the start will pay off big time in the long run. Worst thing you can do in this hobby is rush in half cocked.
Updated the Plan as condenser was spelt wrong and i must have been in a day dream when i wrote that the chimney drop is DN10 1/5 inch pipe. I meant to write DN15 1/2 inch pipe
As usual click on the thumbnail to enlarge the image
I have not drawn up the centering ring because I'm not 100% certain on the exact location it should be placed.
I'm fairly sure the internal diameter of the centering ring should be the same internal diameter as the 2 in pipe coming of the tee. Is this correct?
I was also wondering if the shape affects the performance. For example should the centering ring be the shape of a washer or the shape or a truncated hollow cone?
Also i was wondering performance wise would it be better or worse off... if instead of having a 3-2 inch reducing tee if had a normal 3 inch tee reducing down to 3/4 inch in the same location as shown on the plans here? If this was an option would it be ok to not run a centering ring in this location?
Nick
Last edited by NicksExa_N13 on Sun Nov 29, 2009 10:17 pm, edited 1 time in total.
I have not drawn up the centering ring because I'm not 100% certain on the exact location it should be placed.
Either on top of the packing, 2" below the take off port. Or at the bottom of the reflux condenser, an inch or so above the take-off port.
I'm fairly sure the internal diameter of the centering ring should be the same internal diameter as the 2 in pipe coming of the tee. Is this correct?
No, wouldn't presume that. For a start it depends in part on where the ring is located, above or below the take-off port. I use a 19 mm centering ring in a 50 mm column, above the take-off port.
I was also wondering if the shape affects the performance. For example should the centering ring be the shape of a washer or the shape or a truncated hollow cone?
Good questions. Again may depend on where it is located. Main aims are to centre reflux and allow vapour through.
Also i was wondering performance wise would it be better or worse off... if instead of having a 3-2 inch reducing tee if had a normal 3 inch tee reducing down to 3/4 inch in the same location as shown on the plans here?
If you have a 3 x 3 x 3 tee, I would use it.
If this was an option would it be ok to not run a centering ring in this location?
Ok here is the 3x3x3 Tee design i had to use two reducers to get from 3 inch down to 3/4 inch. As i don't think a 3 Inch to 3/4 Inch reducer exists.
I will draw in a centering ring later on both the 3x3x3 and 3x3x3 designs coming straight off the bottom of the reflux condenser as shown in Hooklines post link above
Hi Hookline no i haven't seen that version i guess the expansion at the start of the packed version directs steam entering the packed column into the centre of the collumn and the reducer directs steam of the reflux condensor to the centre of the collumn also. Performance wise would this be a better design than the 3" pipe with a centering ring?
Nick,
One more thing, you want to minimize the distance between the valve and the Tee. IMO maximize the length of the product condenser - I did and my condensate comes out cooler that room temperature
SB
Time flies like an arrow
Fruit flies like a banana Groucho
NicksExa_N13 wrote:Hi Hookline no i haven't seen that version i guess the expansion at the start of the packed version directs steam entering the packed column into the centre of the collumn
Never considered that. Though I suspect that the vapour expands out very qiuckly in the small space inside the reducer.
NicksExa_N13 wrote:and the reducer directs steam of the reflux condensor to the centre of the collumn also.
Only to a certain extent, given it is 2" inside 3", and only if you stick the 2" all the way through the reducer. I would still have a centring ring on the packing, or something.
NicksExa_N13 wrote:Performance wise would this be a better design than the 3" pipe with a centering ring?
Can't give you side by side comparisons offhand. But the end results from most basic versions of a VM or LM column are the same, ethanol around 95%. Main advantage of this design is if you only have limited amounts of 3", and you can use a 2" tee. Main disadvantage is you need a breakable join in the 3" to be able to get the packing in/out.
