Bokakobs slanted plate coloumn

[Grayson_Stewart]

3.1415 x 1" = length of one inner coil = 3.14"
3.1415 x 1.75" = length of one outer coil = 5.49"

For a 5" long coil there would be 5"/.25" individual coils, or 20 coils of each.

[20 x 3.14"] + [20 x 5.49"] = 172.6"

172.6" / 12" = 14.38 ft of tubing required.

This does not account for the run of tubing used to reach the inlet and exit water supply.

1" = 2.54 cm

[Guest]

Thanks grayson, Much apreciated.

[OldStormy]

Hi to the experienced guys,
Advice please. I am considering building an eliptical plate still a la Bokakob but am querying the location of the thermometer as shown on his mini still diagram as it is in the column packing. I would have though just below the collection plate but above the packing would have been better, ie. in the vapour.
Comments please.
Cheers,
OldStormy

[jbrew9999]

Yes, put it above the packing but below the first plate. And there has been some talk of avoiding putting it in the path of the dripping reflux so maybe put it off center or less than half way in.

Also I recommend that your head separates from your column so that you have at least a chance at cleaning flux off of the lower plate.

And don't worry about cutting perfect eliptical plates to solder inside of the head. Just cut diagonal slits in the head and slide rectangular plates into the slits. The rectangular plates can come from a piece of scrap pipe, cut open and beaten flat.

[nimrod77]

Just wondering on the top end cap for the size of the vent hole, is 1/4" big enough?
Cheers

[jbrew9999]

You don't need a cap at all. But if you want one anyway, the hole is just there as a safety precaution so I guess 1/4" would be fine.

[Guest]

My advice (i.e. Alex's advice):

Plate: How will you know how *deep* to cut the slit for the plate? Depth matters so as to not obstruct vapor path! Do the math or email me for a template to help understand. Angle of plate isn't important as long as takeoff tube is submerged by condensate. Top plate and bottom plate should overlap by at least 1/4". Next, the vertical spacing between the bottom of the top plate...and the top of the bottom plate...should be *at least* 1/4". Top plate should be 1/16th (or more) smaller diameter than the coil.

Vent: NO cap at all. Top must be open. Condenser should stop all vapors. Wrap coil with copper packing material, plus, stuff inside coil with same. No vapors should escape.

Thermometer placement: 1/3rd of the way down the packing - just as the picture & instructions of the Mini-Still indicate. This will give you time to adjust to temp changes in column (ie. the content temp and therefore timing of cuts). If thermometer is placed higher and temp rises, by then tails will be in distillate - too late! You gain nothing by having it above packing. Alex made many tests to confirm this.

Flux: use water soluble, then hot water will remove it. Pre-clean column pipe and plates before soldering, then all to remove is the flux with a hot bath, then water test-run.

Just my $0.02, but info from the designer himself. Do as you wish. Mini-Still is great.

Eth&All

[OldStormy]

Hi Guys,
Thanks for the info. jbrew, I had already perceived the problem of the thermometer in the way of condensate - thanks for your response. Eth&All, thanks for the detailed response, very appreciated. I understand the placement of the thermometer a little better now as well as the top plate size.
Cheers,
OldStormy

[jbrew9999]

Alex is talking about soldering the top plate to the condenser. That is why it has to be smaller than the diameter of the coil. You could also just cut a slit for the top plate and install it just like the bottom plate. That way you wouldn't have to worry about what orientation your coil is in in the column. (the weight of your cooling hoses might want to spin the condenser into a certain position. That must be why Alex has that cut-out in the top of the mini-still for the coil tubes to sit in. Either method will work. His restricts the direction your cooling hoses come off the column but makes the lower plate easier to clean. Mine method allows your condeser to spin freely in the head and you don't have to cut any circular plates.

If you do solder the upper plate to the coil, make sure you position the coil so that any condensate that forms on it will hit the plate otherwise condensate from the coil on the 'high-side' of the plate might miss the plate completely and drip right back down the column.

[Guest]

>You could also just cut a slit for the top plate and install it just like the bottom plate. That way you wouldn't have to worry about what orientation your coil is in in the column. (the weight of your cooling hoses might want to spin the condenser into a certain position. That must be why Alex has that cut-out in the top of the mini-still for the coil tubes to sit in. Either method will work.

Orientation is important when soldering on top plate to coil, as described (it's job is to direct condensate to the lower plate). But weight of cooling hose.....I can't imagine that! The weight is minimal with 1/4" I.D. tubing and the amount of water in the hose is trivial (it barely flows out!) so no issue with pulling. If 1/4" copper tubing is wound as double helix coil onto a 1/2" pipe for a mandrel, then it will barely fit inside the 1.5" column (no slop). No way it will turn inside column once hoses are lined out to water supply. There's nothing tugging at it to make it move. This would be an issue if coil is substantially smaller than column; hmmmm - no it wouldn't either! It should be wrapped in copper gauze (e.g. coil in 2" column) there's just no pull on the coil at all from hoses. Cut-outs only put coil lower in the column if desired (careful of vertical spacing of plates!) because the intake/outflow tubing part of the coil sit on top of the column. Cut outs make it sit down flush (but not necessary).

>His restricts the direction your cooling hoses come off the column but makes the lower plate easier to clean. Mine method allows your condeser to spin freely in the head and you don't have to cut any circular plates.

I just can't see the [restricts] problem you describe and I have fed water from left and right and behind. Again, clear vinyl tubing is teeny amount of weight. Not sure of what spinning is all about. Water can be fed from any direction.

If you cut another slot for soldering in upper plate (instead of attaching to coil), do the math good!!!! Hope you don't get it in too deep, nor too close to lower plate. But yes, it does work just as good. Also, be sure to bend down center notch in lower plate before soldering in the upper plate!!!!!!!

>If you do solder the upper plate to the coil, make sure you position the coil so that any condensate that forms on it will hit the plate otherwise condensate from the coil on the 'high-side' of the plate might miss the plate completely and drip right back down the column.

Maybe, but there's a whole lot of dripping going right back down the column anyway - reflux! Condensate follows the circular coil right down to the plate.

Not making a troublesome disagreement, but what you describe doesn't sound like MiniStill I know (like in the picture). Just my advice from actually building/using the MiniStill. Nice discussion! - Eth&All

[Grayson_Stewart]

Orientation is important when soldering on top plate to coil, as described (it's job is to direct condensate to the lower plate). But weight of cooling hose.....I can't imagine that! The weight is minimal with 1/4" I.D. tubing and the amount of water in the hose is trivial (it barely flows out!) so no issue with pulling.

Huh? Faster water flow weighs more than sedentary water?

If 1/4" copper tubing is wound as double helix coil onto a 1/2" pipe for a mandrel, then it will barely fit inside the 1.5" column (no slop). No way it will turn inside column once hoses are lined out to water supply. There's nothing tugging at it to make it move.

You take a filled 3/4" garden hose and attach it to the end of your 1/4" tubing and see if 6 feet or more of garden hose swaying in a catenary arch like a power line doesn't have to be adjusted, rotated, moved, and lined up and the garden hose then tied off to something throughout a run.

Cut-outs only put coil lower in the column if desired

Wouldn't it just be easier to cut off another inch or so to achieve whatever elevation change is required for the coil??

If you cut another slot for soldering in upper plate (instead of attaching to coil), do the math good!!!! Hope you don't get it in too deep, nor too close to lower plate.

What math? Just wrap a string around the column on a slant and trace out a cut line for the top plate....move down whatever depth you desire and repeat with the string for the bottom plate cut. And if Bokokob reads this, I claim copyrights to the string idea

Maybe, but there's a whole lot of dripping going right back down the column anyway - reflux!

Sure is, and if you don't have a upper plate attached to the column by soldering in place that leakage back down the column will prevent you from ever knowing the true total distilate output thereby affecting the reflux ratio you could calculate. Also, you would never be able to use the detuned column as an efficient pot still head or for stripping runs.

[Guest]

Stewart if you want to run a water hose to the top of your column, go right ahead. Yeah I'd say that would pull over the Eiffel tower. But 3/8" O.D. (1/4" I.D.) vinyl supply lines ain't gonna move anything on a Mini-Still no matter which way they're pointing or how full of water they are.

The other points you made...gee, ...I don't know what to say! But hey, that's what forums are for - to exchange ideas. Thanks for comments.

Mini-Still builders - good luck building & using, and hope you like it. It's a dandy little thing that kicks butt. Build it however you want!!

[jbrew9999]

Thanks for the support, Grayson.


Eth&All,
Please note that the stability (structural) of the column is not only affected by the weight of the cooling hoses but also the lenth of the column,and the sturdiness of the boiler top (lid or bowl).

[manu de hanoi]

advice : calculate the height of water your steam will have to go through, that will give you the pressure in your boiler-----> your joints ( flour paste for example) might not hold the pressure.

[scree]

3.1415 x 1" = length of one inner coil = 3.14"
3.1415 x 1.75" = length of one outer coil = 5.49"

For a 5" long coil there would be 5"/.25" individual coils, or 20 coils of each.

[20 x 3.14"] + [20 x 5.49"] = 172.6"

172.6" / 12" = 14.38 ft of tubing required.

This does not account for the run of tubing used to reach the inlet and exit water supply.

1" = 2.54 cm

I basically did the same exercise except I worked backwards instead.
I figured on using 20' of 1/4" tubing.
Diameter x pi for the outer coil + diameter x pi for the inside coil.
I figured 2 turns per inch rather than 4 to allow for 1/4" spacing. For a 5" coil, it would take 10 turns for each coil.
In this case if I wanted 10' of tubing, I would add 3.14" to 5.49" for a factor of 8.63".
10' or 120" divided by 8.63" would give the number of wraps.
120/8.63= 13 wraps with about 8" remaining for connections or 12 wraps with around 16" for connections.
12 wraps would make a 6" condenser.
In my case, with a 3" outer coil and 2" inner, for 20' of tubing, it took 17 wraps for each coil or just over 8".

I notched the top of the head to fit the tubes. With a spot of solder they don't rub and the condenser is kept centered.

I wanted a lid to keep out dust as well as protect the ceiling in the shed from hot air.( Speaking of hot air...) Anyways,
I used a flat piece of thin copper sheeting for the lid. I soldered a finger (dead finger?) to the bottom of the lid that sets in the middle of the condenser. The finger has a good 1/2" of clearance, so it is not a tight fit at all. The whole thing is very light and unobstructed so that with any rise in pressure, it will work as a relief valve.

[scree]

A 30 cm (11.8") long coil in a 2" column? I understand that 6" is plenty. I have 8" in a 3" and it's more than plenty.
http://homedistiller.org/forum/viewtopi ... 17&t=16225