Ponu still

[warr87]

I am interested in building a ponu at some point (probably not for a few months, but researching it for the moment). I know some of you on this site have been confused about its design and functioning so I'm going to provide everything I have found and hope to get some fruitful discussion on this design .

Here are some images that I have found:

"Ponu 1"

"Ponu 2"

"Ponu 3"

'Ponu 4"

"Ponu 5" A possible modification of the last (not something I will try, but thought I'd add it anyway).

ponu5_experiment.gif (5.83 KiB) Viewed 1783 times

My confusion:

In the diagram for "Ponu 1", it shows the largest tubing (going off to the right) as the one circulating back to the still, with the smaller tube being connected with the take-off porting that runs through the condenser. Also, this design has a vent to the atmosphere up the top (on the largest tubing). Also, I'm not entirely sure which tube is connected to the water-trap/lower coil. i find the same confusion with "Ponu 2". The difference with "Ponu 2" is that it does not show a vent to atmosphere.

"Ponu 3" is a detailed drawing though I am confused by the fact that the lower coil is connected to the take-off line as well as the secondary tubing that runs through the condenser. It is confusing for me because I was under the impression that the water-trap boiled off the vapor to be sent back up again, but the only way to the take-off tube is through the coil. Does this mean that the alcohol vapor is flashed off in the coil so that it rises up and through this take-off line and mixing with the liquid from the secondary tubing?

"Ponu 4" is a great illustration. If you remember that the coil has been removed from its chamber to show its purpose, as well as the fact that the coiling chamber has been split in half to emphases the different directions, then this shows how the ponu is operating. Also, the bottom of the lower coil is a little misleading, it remains pointed up so it does not go directly back into the boiler.

"Ponu 5" is proposed modification for the ponu. IMO I don't think it would work, at least how its proposed. It is an interesting idea though to increase the amount of reflux going on.

I do have questions: 1) How do you adjust the rate of take-off? A needle point value on the take-off line would only make liquid build up in the coil, and though some would go back down I'm not sure how helpful it would be with the ABV%/reflux action. Though maybe someone has a better thought on this? 2) Some designs have a vent to the atmosphere and some don't. Depending on where this is, I think this would merely let the vapor escape instead of being taken off. Is a vent necessary in this particular design?

I hope ozone doesn't mind this, but the following is from ozone about the action of the ponu:

I'm figuring out that these are the key elements..A--lower coil length, too long water flashes off with the alcohol, too short and the alcohol drops back into the pot. B-- The longer the distance between the secondary coil inlet and the lower coil inlet the smoother the still runs (this adds some height to the still, but minimal), shorter the distance and it "cycles the alcohol out more than flowing steady. As well you get two flash off and condensing cycles before it leaves the still, so you theoretically say it been double distilled.

With a ponu it's all about surface area on that lower coil.... I was able to install a wide but short coil in the 6", with the 3" it would be a longer but narrower coil (more like the first one I built).

Threads of interest:

http://homedistiller.org/forum/viewtopic.php?t=14533" onclick="window.open(this.href);return false;" rel="nofollow < ----- ozone's 6" ponu.

http://homedistiller.org/forum/viewtopic.php?t=15323 < ------ hstuurman's ponu.

My plan:

I want to build a short and compact ponu probably using either 2" or 3" copper. I can definitely get 2" pipe but I'm unsure about 3" right now. Since I want this for an apartment I was thinking that the lower coil to be around 12"-18". I'm unsure about the length of the upper coil. According to ozone, the 'longer' the distance between the two the smoother the still will run. Since the second coil is sitting inside of a water-cooled chamber, the wider the chamber the more length of tubing could be used, theoretically (at least i think :S) the greater the distance. I'm trying to add as much length as possible without going that far up.

If anyone has any theoretical numbers or ideas to throw around, I'm all ears .

[ozone39]

PONU #4 is a good break down of how the design works. PONU #5 is a very interesting concept, ran throgh the flow pattern 4 or 5 times and and do not see any reason for it not to work. In theory #5 would flash off and re-condense the alcohol 6 times.. Lower coil primer valves would be needed so that the alcohol/water vapor does not go backwards through the lower coils at start up )I put these on my ponus reguardless, helps with cleaning and flushing as well)...As far as the rate of take off it's all by sence and percentages. You can control output buy controling the heat input, but generally the slower you run the still the higher alcohol % you get. I figure head shots by % and time, hearts are based on % and taste, tails (most of the time very small) I drop into a seperate container. I do a rather aggresive heat up of the wash till the wash hits 200F (I have a thermometer in my boiler chamber just for this purpose) then turn theflame to low fire, still pretty much runs on auto pilot after that...

[hstuurman]

Ponu 3 is the same as ponu 4. In 1 & 2 the 10mm tube (big one looping up, and down to the big coil) is drawn right, in 3 it is drawn left. This is the blue tube in ponu 4. The smaller tube conneted to this one (red in 4) is going to the final condensing-coil.

I've made some changes during the build, the 10 mm tube through the cooler isn't placed beside the 6 mm coil, but inside, and the T on the top isn't placed, this I recommend, cause it gives you the oppertunity to back-flush the coils for cleaning (see ozon's still).

Ponu 5 is interresting, never seen this set-up. I think the Ponu is an interesting design, with many oprtunitys. See the 2 still's Ozone build, and mine smaller one.

[ozone39]

I would not install any needle valves any where on this design. Once the lower coil gets hot and starts flashing off alcohol all you have to do is control the heat input (burner) so that the wash just sits there and simmers slowly (enougt to keep is boiling). The still will pretty much adjust itself from there...I do have a temp gauge on my condeser so I can keep track of that, I generally run around 85F. I do this so the alcohol that ends up in the parrot is not to hot (this condesor also controls the temperature of the final product comming out).

[warr87]

Ponu 3 is the same as ponu 4. In 1 & 2 the 10mm tube (big one looping up, and down to the big coil) is drawn right, in 3 it is drawn left. This is the blue tube in ponu 4. The smaller tube conneted to this one (red in 4) is going to the final condensing-coil.

I've made some changes during the build, the 10 mm tube through the cooler isn't placed beside the 6 mm coil, but inside, and the T on the top isn't placed, this I recommend, cause it gives you the oppertunity to back-flush the coils for cleaning (see ozon's still).

Ponu 5 is interresting, never seen this set-up. I think the Ponu is an interesting design, with many oprtunitys. See the 2 still's Ozone build, and mine smaller one.

By writing it all out I think I solved any problems I was having understanding the still, lol. Also, I was thinking the same thing as you, place the 10mm tube through the cooler down the middle of the secondary coil. I assume it was draw like that to show the separate pieces of the still.

As for the T, I was thinking: would an angled T, such as a SAN or COMBO Tee make the vapor path more efficient (going towards the secondary coil/cooler)? I'm unsure if this is a stupid question or not since I haven't built one before.

As for Ponu 5, I was unsure about it because I was under the impression that multiple heads connected to the boiler would result in one being more dominant than the other. But since there is actually only one entry into the process (drawn on the left hand side) I don't think that would be a problem. This design would work better for those wanting more reflux for their vodkas.

[Adverse Effects]

I am interested in building a ponu at some point

its an interesting unit that is why as far as i know i was the first to build one off of a concept drawing i found on a site 7 or 8 years ago (was not English so all i had to go on was a small drawing with no real measurements)

"Ponu 3"

looks like a drawing someone did of my build and sizes i gave

My confusion:
In the diagram for "Ponu 1", it shows the largest tubing (going off to the right) as the one circulating back to the still, with the smaller tube being connected with the take-off porting that runs through the condenser.

doing it that way will work just not as efficient flow path as it could be but that is just a drawing what is made in real life would be different

Also, this design has a vent to the atmosphere up the top (on the largest tubing).

i have made my unit able to pull apart in to 2 units for cleaning

at the T and next to it you can see 2 brass compression fittings undo both of them and there isnt any where i carnt use a high pressure hose to clean

Also, I'm not entirely sure which tube is connected to the water-trap/lower coil. i find the same confusion with "Ponu 2". The difference with "Ponu 2" is that it does not show a vent to atmosphere.

you do not want to vent to atmosphere you want it to stay in there till it go'd through the final cooling coil

"Ponu 3" is a detailed drawing though I am confused by the fact that the lower coil is connected to the take-off line as well as the secondary tubing that runs through the condenser. It is confusing for me because I was under the impression that the water-trap boiled off the vapor to be sent back up again, but the only way to the take-off tube is through the coil. Does this mean that the alcohol vapor is flashed off in the coil so that it rises up and through this take-off line and mixing with the liquid from the secondary tubing?

in the lower coil you have 2 things happening

cooled liquid dropping down from the top cooling tank as it runs down the lower coil against the lower side of the inner wall of the coil as its doing that its getting reheated so the alcohol flashes off again and the non alcohol liquid continues to go down the coil the alcohol vapor go's up against the upper inside wall of the lower coil to the T in-between the 2 tanks the cold liquid falling has a tendency to push the reheated alcohol vapor out the side of the T and up to the top coil in the final cooling coil
hope that helps

"Ponu 4" is a great illustration. If you remember that the coil has been removed from its chamber to show its purpose, as well as the fact that the coiling chamber has been split in half to emphases the different directions, then this shows how the ponu is operating.

yes this is a exploded view i did for someone that could not work out the flow of the unit

Also, the bottom of the lower coil is a little misleading, it remains pointed up so it does not go directly back into the boiler.

i couldnt think of a better way of showing it so i just added a pipe on to the end of the water trap / water valve

"Ponu 5" is proposed modification for the ponu. IMO I don't think it would work, at least how its proposed. It is an interesting idea though to increase the amount of reflux going on.

this is something i was bouncing around wondering if it would improve things at all but decided that for all the extra work would be for a small gain so i never built it

I do have questions: 1) How do you adjust the rate of take-off?[/quote]
heat input

A needle point value on the take-off line would only make liquid build up in the coil, and though some would go back down I'm not sure how helpful it would be with the ABV%/reflux action.

noo you never want to restrict the output as this is the only pressure relief the unit has
the only valve you want on this unit is a small one on the input of the cooling water my unit used a very small amount of cooling the flow was about 2/3 as thick as a match-stick

2) Some designs have a vent to the atmosphere and some don't. Depending on where this is, I think this would merely let the vapor escape instead of being taken off. Is a vent necessary in this particular design?

as said above no venting is good venting on this unit

Threads of interest:

http://homedistiller.org/forum/viewtopic.php?t=14533" onclick="window.open(this.href);return false;" rel="nofollow < ----- ozone's 6" ponu.

http://homedistiller.org/forum/viewtopic.php?t=15323" onclick="window.open(this.href);return false;" rel="nofollow < ------ hstuurman's ponu.

my build with some pics back in 2008

Lower coil primer valves would be needed so that the alcohol/water vapor does not go backwards through the lower coils at start up

not needed as the the U bend on the lower coil fills with in seconds of the pot getting up close to temp

I put these on my ponus reguardless, helps with cleaning and flushing as well

not needed i mentioned above how i can clean mine

As far as the rate of take off it's all by sence and percentages. You can control output buy controling the heat input, but generally the slower you run the still the higher alcohol % you get.

http://youtu.be/NfEw4KZ1Qh8

I figure head shots by % and time, hearts are based on % and taste, tails (most of the time very small) I drop into a seperate container. I do a rather aggresive heat up of the wash till the wash hits 200F

that is basicly how i do it as well but i have found that you dont get much tails

still pretty much runs on auto pilot

i thought that it was one of the things i really liked about this still

Ponu 3 is the same as ponu 4. In 1 & 2 the 10mm tube (big one looping up, and down to the big coil) is drawn right, in 3 it is drawn left. This is the blue tube in ponu 4. The smaller tube conneted to this one (red in 4) is going to the final condensing-coil.

yes

I've made some changes during the build, the 10 mm tube through the cooler isn't placed beside the 6 mm coil, but inside, and the T on the top isn't placed, this I recommend, cause it gives you the oppertunity to back-flush the coils for cleaning (see ozon's still).

the vent is not needed the way i built it (explaned up a bit)
yes i run the the main tube down through the center of the top coil i just drew it that way to make it easier to see what is going on

I was thinking the same thing as you, place the 10mm tube through the cooler down the middle of the secondary coil. I assume it was draw like that to show the separate pieces of the still.

that is correct just made it easer to see for others

As for the T, I was thinking: would an angled T, such as a SAN or COMBO Tee make the vapor path more efficient (going towards the secondary coil/cooler)? I'm unsure if this is a stupid question or not since I haven't built one before.

i dont think the increase in efficiency would be worth the effort and complexity

As for Ponu 5, I was unsure about it because I was under the impression that multiple heads connected to the boiler would result in one being more dominant than the other. But since there is actually only one entry into the process (drawn on the left hand side) I don't think that would be a problem. This design would work better for those wanting more reflux for their vodkas.

yes that is why i was playing around with the idea when i drew that also heads 2 and 3 would not need to get as hot because the % in each one would be higher then the previous one there for not needing as much heat to flash off