Spiral Pot Riser

[myles]

Please don't confuse this with the locked post below titled "Question about the Spiral Still". This is a post about a POT STILL and not a reflux still.

I have a nice copper coil that I am working on. 1" tube that has 7 or 8 coils about 10" or so in diameter. Picture to follow as I am still cleaning it up.

This is the MASH version which I would not recomend as I suspect it would surge.


I am thinking about incorporating it (as a vertical coil not like the horiziontal one seen on MASH) as the riser on my glycol pot boiler.

Used for stilling on the grain with moderate power, it should introduce a little bit of reflux due to the longer vapour path. With 1" tube it should be OK for vapour and natural reflux to be in the tube at the same time.

You sometimes see illustrations of oldtimers stills with a vertical spiral vapour path over the boiler. Just wondering if any of you pot stillers out there have actually run one like this.
Myles

[rad14701]

Hey, myles, I entertained the horizontal air cooled worm some years ago... My thinking was that it would perhaps induce a small amount of reflux in the lower halves of the coils... I think you are right about the potential for surging... Surely there must be some way of negating or at least diminishing the amount of surging...

[mash rookie]

Hey, myles, I entertained the horizontal air cooled worm some years ago... My thinking was that it would perhaps induce a small amount of reflux in the lower halves of the coils... I think you are right about the potential for surging... Surely there must be some way of negating or at least diminishing the amount of surging...

I really like the idea of the horizontal coil. Interesting.
First thought is size of tubing. It needs to be large enough that vapor can push through liquid collecting at the bottom of the spiral yet small enough that liquid will collect and create a trap so that vapor has flow through it like what we see on a plate still.

With the one inch tubing, minor surging should not be an issue it would be part actually part of the process. Although not being able to return liquid to the start for true refluxing, it does seem like there would be a reflux action.

I use a simple clear tubing loop on my ferment buckets as air locks. I visualize the horizontal worm bubbling like that at each loop.

I would love to here how it performs. Simplicity, air cooled, Refluxing? I love it.
Keep it up Myles!

[rad14701]

Think along the lines of coiled thumpers... I even pondered overflow tubes to maintain a maximum fluid level in the coils...

EDIT: To Add...

My thinking is that small tubes made of 1/4" or smaller could be run between mid-way up each coil and the bottom of the preceding coil... The tube should be attached to the outside of each coil as any vapor will tend to hug the inside of the coils... This will help insure all vapor travels through the coils rather than sneaking through the thumper return/leveling tubes without the need for airlocks... Whether a reflux tube on the first coil would be need is debatable and might depend on where the height of the vapor inlet, whether on the high side or low side of the initial coil... That's my thinking anyway...

[myles]

No folks I want to fit it vertically not horizontally. I have not fitted the spacers to maintain the pitch angles yet but this will give you an indication of what I am thinking of.



So whad do you think this will look like when connected to this?

[Prairiepiss]

A UFO.

Rad if you put some sort of reflux return tubes on the coil . Wouldn't you need a vapor trap of some sort on them?

[rad14701]

Rad if you put some sort of reflux return tubes on the coil . Wouldn't you need a vapor trap of some sort on them?

I don't think you would if the tubes were positioned properly... But at this point the concept is a bit off topic...


myles, that would look sweet...

[Prairiepiss]

Ok I'm sory I thought you were talking about the coil in the position that myles is working with.

And myles I think it will look great. I couldn't help myself on the UFO comment.

I was thinking. That if you are worried about it surging. You could posably make the distance between coils at the bottom more than the top. this would make a steeper incline where more reflux return is letting it flow back to the boiler faster. with less chance of pooling.

[myles]

At the moment the coil is only 16" high. It is 21 foot long and is going to be expanded to closer to 3 foot tall to increase the slope angles. I may even chop out a coil or two, but either way I don't think pooling will be an issue.

The surging comment was actually aimed at the horizontal coil. Which does have some potential and would be more efficient on an angle like an archimedes screw. HOWEVER, it would clearly be a variation of an inclined reflux column (and a bit of a curiosity) and as such would be in the column section and not here in the pot still section.

[myles]

I think that I named this post wrong. It would be more acurate to call this a spiral lyne arm.

Anyway however she is named she looks like this.



She needs a vinegar bath and a polish but basically she is good to go. I misscalculated the balance just a touch, but not enough to be any sort of problem.

I think I will give her an air cooled coil condenser to play with, even if it needs a boost with a fan or something to finish off.


(older picture before I chopped a few coils out)

Yes I know it will look a bit like a "spiral still" but this is definitely a pot still and will be run as such. She is destined to go on the glycol double boiler.

[myles]

Things have moved on a bit (slowly) and I built a new connector for the spiral riser.



The riser was shortened a bit and the section cut off was turned into a 3 core spiral liebig to match the riser. The connector is the standard 'beefed up easy flange' with the copper tube turned over to make the mating surface. I use a brass rod instead of copper wire because I like the look. Off course it is a bit harder to work in but I made a mandrel for the pillar drill so that after roughly grinding it down with a bench grinder, I could finish off with abrasive paper on a wooden stick.



You won't see it when the clamp is on off course, but I know it is there.

[Odin]

This should give you extra reflux, Myles!

It reminds me of a really funny Swedish still. Made from these 30 liter bucket fermenters. Just make a sugar wash, they suggested. When it is done, rack it of, let it clear, then put it back. On the lid they put a coil like yours. Only thinner and with around 14 to 15 windings. So light, no struts in between the coils. After 14 or 15 windings, it would go down in another 14 to 15 windings. Inside the fermenter vessel (now boiler) they would put a 25 or 50 watts aquarium heater. The mash would not boil, but the slightly increased temperature and many coils would, in about 3 weeks time, give you a few liters at 95%. I actually read posts of people using it and stating that the claims made were true! Only problem was heads & tails seperations could not be done.

I think the amount of reflux you get will be ugely dependent on how much energy you throw into your boiler. With really low energy input, there might be a prettry drastic increase in ABV, I reckon.

Odin.

[myles]

To be honest Odin, those spiral stills are running at very low power ( hundreds of watts only). They need to because they are intended to be reflux stills, and use air cooling to profide the reflux that runs back down the coil. This is going onto a copper double boiler and the coil is bigger - about 1" diameter tube and it will run on 2 to 3 kw.

The intention is to run at very low power at the start to get some degree of heads compression, but really this is just a pot still. I used the coil mainly because it was there and I wanted to find something to use it for. In the process I have also got a nice coiled liebig to match.

I think of this as a pot still with a long 1" lyne arm that rises on a slight upwards slope, and just happens to be wrapped into a coil to save space. I will be reserving this for stuff that needs to be heated gently for basic single or double run distillations, but on the grain or fruit pulp for maximum flavour.

I quite like the idea of stripping the cleared part of the fermented wash, and then adding that back to the boiler with the rest of the fermented fruit pulp (or grain) for a spirit run. Not quite a double run, more like a run and a half.

[Ian Jay]

That's a great finish on the copper.

[Odin]

@Myles: a run and a half is the way to go if you want taste! I do it all the time and love it.

Odin.

[myles]

Yes Odin, I have heard others talking about it but never really had the right equipment before to allow it.

Ian I just invested in an Erbauer bench grinder, 6" and 375w/230v. I took both stones off and have fitted spindles to use 6" polishing mops. I have a set of 3 mops, 1 sisal, 1 stitched cotton and 1 loose cotton, and that was the 1st bit of work that I have tried polishing with it. I am rebuilding all my equipment and reconfiguring my still room, and intend to polish everything that stands still long enough.

[emptyglass]

Yes Odin, I have heard others talking about it but never really had the right equipment before to allow it.

Ian I just invested in an Erbauer bench grinder, 6" and 375w/230v. I took both stones off and have fitted spindles to use 6" polishing mops. I have a set of 3 mops, 1 sisal, 1 stitched cotton and 1 loose cotton, and that was the 1st bit of work that I have tried polishing with it. I am rebuilding all my equipment and reconfiguring my still room, and intend to polish everything that stands still long enough.

Cant wait to see pics of your polished......I like shiny things. Got some good rouge?

I had a poorly made worm once upon a time, had flat spots, not enough to surge, but enough to smear cuts.

Makes me think, what if you introduced some flat spots to the spiral "leibig"?
As it is before the condensing stage, before its undesirable for that smearing effect, do you think it could be used to create the reflux you are looking for?
If in the right place/s, with the right downturn, it would act like a re-bioler sort of deal, given the 1 inch diameter.
I'm thinking you would need it to turn it down at least 3/4 the diameter of the tube, or possibly 1x the diameter if you wanted to create puddles of reflux.
Depends on if you want the reflux going back to the boiler, or re-boiling in the spiral.

If you want it returning to the boiler, just make the helix angle bigger. Like a steep arm. The length (and running environment) would then determine the ammount of reflux

Well thats my take, tell me to go to the back of the class if I must. Nothing I have done with a pot has beat running it through twice.

My wife still watches mash all the time. I'll have to pay closer attention.

[myles]

emptyglass the spiral liebig I was refering to isn't that coiled pot riser, it really IS a spiral liebig. It is going to be the product condenser on this still.

It is in this post http://homedistiller.org/forum/viewtopi ... e#p6913441 but as a taster here is an photo taken part way through the build.



That is 3 vapour tubes inside a single water jacket.

[myles]

I have now combined the liebig and spiral riser and am building them into the copper double boiler. Please see this thread: http://homedistiller.org/forum/viewtopi ... 3#p6891123

[Kareltje]

Wow!!!!
I thought I was original, but someone has already thought the same things.

Very impressing!

[raketemensch]

Damn, myles, nice work.

[eStill]

How well did the spiral riser work? Do you have a pic of it all assembled? Was this as a replacement for the reflux column? I'm looking for an alternative to a 2in copper column. I was considering a gentle spiral of 1in pipe. I've never seen it done before. Is it worth a try?

[Kareltje]

On my former still I had a riser of 28 mm inner diameter and 50 cm length.
On my present still I now have a riser of 13 mm inner diameter and 2 m length, plus a 25 cm connection to the still. I curled the 2 m to a spiral of about 5 windings of a total height of 25 cm.
The effect on the %ABV of both risers seem to be more or less alike. Not surprising as the content is almost the same. The winding does not have an influence on the content, maybe on the heat exchange.

Only problem might be: I sometimes filled the straight riser with copper curls for a packing to enhance the effect. I did not yet figure out if I can imitate some packing in the spiral. Maybe some small chain, as long as it does not block the gas stream in any way. Or maybe a pipe of 3 m length would compensate for that.

[eStill]

So, how would a 1M 50mm dia straight vertical column (of the sort we often see here) compare to a 2m spiral of 22mm diameter, for example?

[Kareltje]

So, how would a 1M 50mm dia straight vertical column (of the sort we often see here) compare to a 2m spiral of 22mm diameter, for example?

My calculation is simple: h*pi*r^2 is the volume. So for the first: 1.000 mm * 3,14 * 625 mm2 = about 2 litre.
2000 mm * 3,14 * 121 mm2 = about 0,75 litre. (Supposing that the 2 m is the length of the pipe, not the height of the spiral!!)
To get the same volume you would need a 22 mm-pipe of about 5,3 m length. Whether this length is curled or spiraled or straight is hardly important. I think! (Maybe for flavour?)

But as I already said: a straight pipe of 50 mm diam can easily be filled with packing, but this is more difficult than filling a 22 mm pipe, especially when curled or spiraled.
And another point but mainly of esthetics (or balance!!): I found it a challenge to position the spiral more or less in the middle on top of the kettle. Did not succeed perfectly, but sufficiently.

In the other direction: what about a column of 100 mm wide and 25 cm high? More like a helmet?

[der wo]

For a reflux still the diameter of the column and the wattage must be in balance.
If you have a column with 22mm dia, it will flood easily even without packing. With packing perhaps at 0.5kW. Because the high vapor speed hinders the reflux coming down. Bended to a spiral will make the flooding worse, because the reflux would flood even slower down.
If you have a column with 100mm dia, you would get many redistallations only, if you heat it with much power, perhaps 7-10kW, or the reflux will come too fast down compared to the vapor speed redistill it. So a 100mm column feed with 2kW will result in less purity than a 50mm column with 2kW.

So deciding the diameter of a column is easy, if you know how much wattage you want to use.
For example, if you only want to use 2kW, it's not necessary to upgrade from 2" to 3". And that's why you see here 2" or 3" mostly.

You can read such basics on the parent site too:
http://homedistiller.org/theory/refluxdesign/diameter" onclick="window.open(this.href);return false;" rel="nofollow


The spiral pot riser is only for pot stills. You can not add a reflux condenser on the top without flooding it.
Because the thin spiral has much surface, its passive reflux is high. Because it's a spiral, the passive reflux is slow, so it gets more redistilled.

[eStill]

Whether this length is curled or spiraled or straight is hardly important. I think! (Maybe for flavour?)

I'm happy enough with the equation for the volume of a cyinder, but I think the above is one of two key points. is the volume of the column all we care about?

The other point being: does it really not matter if the "column" isn't vertical?

[Kareltje]

Whether this length is curled or spiraled or straight is hardly important. I think! (Maybe for flavour?)

I'm happy enough with the equation for the volume of a cyinder, but I think the above is one of two key points. is the volume of the column all we care about?

The other point being: does it really not matter if the "column" isn't vertical?

Der Wo had some interesting points about the interaction of heatflow and size and shape of the column.
I have no experience with that, as I am limited by the capacity of my condenser: I regulate my burner so that the destillate comes out at an acceptable temperature. And then see what comes of it.
Latest comparison: in pot still mode I ran at 0,53 W, with the spiral I ran at 0,61 W. 8 ltr of 37 % ABV made 70 % ABV and 80 % ABV, both at about 3 ltr. But that depends on cuts too, of course.

I tried to use the spiral horizontally as a series of small thumpers. It gurgled, at first quite strong, but later on at a steady pace. And it danced a bit too. Nice sound and sight.
But I have to try that again in order to tell more about it. I plan to compare it with other constellations, but that will take some time. So I do not know if it really does matter. Or how really it matters.

[Kareltje]

At last I have some tests and pictures.
This is the pot still. Inside the shiny coat at the left there is a copper boiler of 10 l. The spiral at the right is a ss spiral of a total lenght of 7 m.
This is the still with the vertical spiral. Its total lenght is 2 m, the height of the spiral is about 25 cm. The height of the pipe underneath is about 25 cm too.
This is the horizontal spiral, that I call wokkel. I planned to imitate a series of 5 mini-thumpers. It bubbled a bit and the system of wokkel and cooling spiral did dance on the rythm.

[Kareltje]

This went too fast.
The test results are like this.
Stripping runs, starting from a wash of about 11 %ABV.

Of course the legenda is in Dutch, but should be easy to understand. liter = litre, vol-% = %ABV, destillaat = distilate, ketelrest = rest in the boiler. Potje deserves some explanation: this is the %ABV of the sample at the end of the sampling time. So this is not the graph of the output the parrot.


Different runs, but both starting from low wines of about 37 %ABV. Voorloop = heads, naloop = tails, Kippenvoer = the product of chickenfeed, 15 Marins = the product of would-be rum.

Yesterday I ran a wash of 35 %ABV with the spiral at only 0,381 kW and got 90 %ABV.
When I fired up I got 75 %ABV.

Edit: Oh, and the x-axis is in minutes. And as the heatflow was constant, easily recalculated to kWh.