Idea, tell me why it won't work

[Absinthe2001]

First of all, Hello, this is my delurk message. I have an idea that I am in the process of trying, but since I haven't seen but one example that was anything like it, I'd like to hear why what I am thinking is wrong.

First of all, my main interest is in essential oils but that should not be germane to this situation, since I am guessing the underlying design flaws will be the same.

I just purchased at auction for a whopping $2 a lovely SS 4 qt Revereware pressure cooker. This will be my boiler. I am not concerned about the size since I am not trying to distill 5 gallons of mash, but rather a couple pounds of botanical material. But I digress. So I went to the local home center and purchased some copper. I got a threaded 1/2 adapter male and female. I plan on removing the tiny valve from the center of the lid and re-drilling it to fit this pair of adaptors, hoping that if I screw them together tight enough I will not need additional gasketting, after all there is none in use with the SS valve that is there right now. Once I have them in place I will be able to either solder or dry fit a 1/2 copper pipe on to it. I plan on doing 2 corners on that so that it is a very simple still head with no additional column and after the 2 corners connecting it to the condenser.

Here is were I am expecting the problem. I have only seen one still for sale that used a design like this, as all the ones I have seen here use running water so bear with me and help me to understand where my thinking is flawed.

I got 20' of soft coiled 1/4" L copper tubing. I also picked up an igloo cooler (the round ones that you fill with drinks and dispense with a push button spigot on the bottom. I drilled a hole in the bottom, and one in the top (side) and placed the coil in there with one end sticking out the bottom and one sticking out the top. My plan is to connect the output of the still head with a reducer to the top of the coil, fill the cooler with ice and water, and perhaps a little salt, (or even who knows, maybe dry ice ) and simply use the bottom of the coil as a drip spout. To me, 20' of 1/4" tubing seems like a lot of surface area, and what I am guessing to be 5 or so gallons of ice water would be a pretty good heat sink.

Once I get some silicone sealant around the drilled holes I will try a run with water to see if I have simply designed a steam jetty or a still.

I am not looking for spoon feeding, or specific EO info, as I know this is a forum for beverage based distilling. I do feel that there is enough in common that there should be some transferable concepts. And to me it seems odd that if everyone is using running water, I can't be the only person to think of chilling a long coil in a bucket of non running water so I am seeking the counsel of the wise.

I assume, that with this as a simple design, I could expand later by making a proper column and even a proper water jacket condenser but I just want to see somethign work

[Hawke]

What you are making is a potstill. The 1/4" tubing is going to make it run extremely slow. Maybe 100ml an hour?
There is nothing wrong with using a worm in a bucket, but 1/4 inch is pretty small.

[blanikdog]

Agreed Hawke. My original pot still had 3/8" coil and when I recently changed to a new 3/4" coil I was amazed how much it sped up the process. I can now do 40 litres in the same time as it took to run 25litres. A bit longer to heat up, but that's minor when compared to output.

blanik

[ImaDKrook]

I am a rookie myself but I would say 3/8 as well the most important thing is to keep it bigger before it gets cool. It takes a large volume of vapor to equal only a little bit of liquid. As far spending the money for a cooler not necessary. A five gallon bucket is free from many sources and five gallons would not get warm at all with a 4 liter pot. Top six inches might warm up but not much more. I would try to get one stainless fitting welding into the top (pots are probably too thin to drill and tap) and then adapt to copper or whatever(safety). Keep it at 1/2 or 3/4 until it gets near the water because volume for vapor will be your friend until it condenses. Making the worm will be so easy if you just buy one single box of canning salt take a funnel and fill it then wrap it around something to coil it (obviously it will be something that will fit inside of the bucket with some space left over). It will take less than 15 min. total time. Instead of trying to put caps on it merely bend the tubing with vise grips and press/roll it really hard (heck flatten with a hammer) and it will hold, then cut off both ends. Lowe's has $2.00 water hose to 3/8 compression fittings to wash out the salt. The tubing full of salt keeps it from flatting out while winding. May take an hour or so for the salt to break loose and come out after turning on the water. Do not use sand it will be harder to get out plus it will be harder to get in. Keep the coil going down hill so your take off will be smooth and not spit. Do NOT install a valve. It would blow up! You say duh but some folks ............. Oh buy refrigeration type tubing it will coil much easier.

My three cents worth.

Krook

[Absinthe2001]

I just measured the tubing and it is .315 ID and .375 OD. Perhaps that is larger than what I said. I do hope this will allow more 100 ml/hr it would seem to be larger t han standard laboratory glass.

Anyway, thanks for mentioning the "worm in a bucket" term. I guess it is much easier to find examples of something when you know what to call it. I certainly could not believe that I had invented it I saw (and of course can't find it now) a small desktop one powered by a sterno or something like that and in the "worm in a bucket" it seemed to take ice cubes (maybe twice the size of a large rocks glass). I couldn't imagine that it made too much at a time but it was pretty and would look cool on someone's desk.

Well I never made it to Lowes today to get the silicone so another day on that. As for the rest of the design I had just a couple questions.

The hole in top of the pressure cooker is pretty small. So my plan is to replace it with a copper connector That is threaded male on one end and slip fits onto standard water copper pipe. I will call this 1/2" but it mics out to .535 id .635 od for actual size. There is also a corresponding female threaded variety of this item which I will be using as a nut to fasten it. I will obviously be redriilling the hole to allow these adapters to fit. Will screwing these two together in a hole cut pretty tight to them be sufficient or do I need some kind of washer/gasket?

When making the attachments to the adapter it is possible that I could connect with a friction fit or I could sweat it with solder it. Do I want to permanently solder this whole contraption all the way from the pot top to the "worm". It would seem cumbersome to break down and clean in such a situation. Possibly I could just solder the still head from the pot top connector through the 2 90 degree angles and then friction fit it to the "worm". My issue is the nature of portability and storage.

On the other hand, since I haven't soldered anything yet, should I be thinking about making a column? Or perhaps a larger still head? As it is, I am not planning on making the still head any taller than necessary to be able to have a good downward angle into the "worm." Is there a better school of thought on that?

Granted the reason I have designed it the way I did was to simulate the ones I have seen for steam distillation made from lab glass. They come with either a 1 or 2 liter steam vessel and similar sized bio vessel all connected with laboratory pipe or direct glass connections. But since I shifted paradigms to a design that runs off the stove instead of a Bunsen burner I am willing to accept counsel from people that design these to run in this way as a matter of course.

[Hawke]

You will most likely need some type of gasket between the lid and the connector.
You could also buy a 1/2" union and a reducer to go from the riser/arm to the worm.
Joints will need to be soldered or use flour paste to seal.

[goose eye]

you aint the first lookin that path. if you backtrack you mite gleen some info.
he was goin comercial best i can rekolek

[Scribbler]

regarding your threading M&F fittings:

I did the same thing on my first still, it was an 8 litre pot with an SS lid outfitting with one of those swivel type venting ports for the steam. My pot still was all 1/2 inch pipe, what I got was a large size threaded male fitting (1 inch) which took a 1/2 inch 'soldered in' pipe at the exit end. my plan was exactly the same as yours, thread it on tight enough and not use gaskets. I ended up using a gasket for two reasons: vapour loss during testing, and also because the bending force of my condenser showed that the thin lid was a little too flexible for my liking.

I got a two iinch by two inch piece of 1/4 inch thick copper from a local metal shop. I drilled it out to allow my threaded male end to slip through and mounted this on the outside of the lid with the female coupler on the inside acting as the 'nut'... I guess I could have used a regular nut if I had found one with a matching fitting, but getting that in stainless steel would have been a hassle so I went the same way you went.

my copper plate helped out the stability issue but not the vapor issue (I hadn't expected it too). therefore what I did before each assembly of my still was to make up some flour dough paste (find the recipe on the forum here as a sticky somewhere...). I put the flour paste onto my copper plate in two rings, one on each side of the hole... I made the ring that would eventually sit against the lid a little thinner as there was a lot of contact area. the ring of dough that would touch the male coupler was a bit bigger... a doughnut somewhere between thumb or finger thickness... once it all screwed together I wet my fingers and ran them around pressing the gasket into the creases just to be safe... then I cut off some of the excess (just to make it pretty) using a butter knife. one quick check again at all the joints and she was good to go.


my condenser was also made with the same type of screw together connecter, but instead of pre-gasketting the deal, I screwed it together until it was tight (but not aligned properly for my in and out water tubes) so then I would back it off the minimum amount required to line things up where I wanted them... then I took a nice big wad of dough paste and rolled it in my hands until it was about 6 inches long and hotdog thickness. I wrapped this piece around the connector.


using this method I never had a single leak, and believe me, regular leak checking is something that I have made a habit of: if you spend time reading this forum you will quickly find out that there is plenty of good advice out there... I definitely appreciate all of the safety consciousness around here... it goes a long way to legitimizing this as a hobby.


is your lid going to seal up tight enough? what does it have for seals? You may want to consider ripping them out if they are rubber or some other chemical based product... you can use the flour dough paste if you do end up tossing the existing seals.

Scribbler.

[Absinthe2001]

The seal is rubber and in good shape. I am not yet concerned about that for the moment. For the most part this will not be processing alcohol but simple plant material and steam. I finally got a connector that I like, it is a 3/4 to 5/8" flare adapter. I am borrowing a friend's flaring tool and that will be the pot side connection to the tubing. The other side of the flare has a fair shoulder and if necessary I will seal the joint with silicone gasket material.

I have applied for a permit, in this state it is a crime even to own a still, but a permit can be had for free for certain purposes. I believe the definition language involves a boiler and a condenser. Until I have the permit the worm and pot will remain separate. I may have to rethink the design a little since I do want it to be able to break down for cleaning and such, now that the still head will be connected with threads and a flare it will allow me to sweat the rest of the still head together and then deal with the connection between the 1/2 and 3/8 of the worm, perhaps I will flare that and be done with it. But I think I need to expose more of the worm at the top to make the connection more flexible, and perhaps reach the sink from the stove.

The next step will to to figure out a way to mount a biomass container so that I can get steam to run through it without condensing on it. As well I need to not get the boiling water on it either.