help with 3 inch stainless VM-LM design

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lucaman
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help with 3 inch stainless VM-LM design

Post by lucaman » Thu May 19, 2011 4:44 am

I want to start building my first still, and would love any advice, suggestions, concerns etc.
This might look a little extreme for a first build but I figure it might as well also be my last. My logic is there’s no point fucking around.

I want to make a 3 inch vm/lm combo. The build will be all stainless except for the top condenser and the packing, which will be copper, and the water lines which will be plastic. I’m using stainless because I can buy it cheap and have access to a good workshop to get all the work done easy. Also I like the lack of maintenance of stainless, and I’ve never really worked with copper much.

We will plasma cut a 3 inch hole in the top of the keg and weld on a 3 inch male connector.
The column, t piece and head will be 3 inch 316 grade stainless.

I will get 6 inches of 3 inch 309 grade stainless turned down to male and female thread. These will be cut into 1.5 inch lengths so that a male coupling can be tig welded to the top of each section and a female coupling to the bottoms. This way all sections can be separated for packing and cleaning. Also the head can be attached straight to the keg for a pot still or stripping runs, and the VM section can be left out if I don’t want to use it.

The colmn will separate into 2 pieces in the centre. Packed column length of maybe 1500mm (59 inches)?

The take off line will be 309 grade stainless ¼ inch hydraulic line with a compression style screw on connector which can easily be moved from ball valve to needle valve as needed. I don’t think I will ever want to use both at once. This will have a liebig type condenser.

For the VM take-off, 1 inch threaded pipe will be welded to the side to make a threaded T for the stainless ball valve. I know this sounds difficult but the right tools are there. Would I be better off with larger diameter, like 2 inch? Also, would this be best to come off horizontally or at an angle?

The head will be a typical Boka dual plate style with either a bought neddle valve or one made from a small stainless T piece using the motorbike spoke design. The top condenser will be the usual dual coiI type. I am not sure what diameter copper pipe to use for this nor what length I would need to make it.

I will put the thermometer inlet below the bottom slanted plate.
I will put 2 centreing rings in the column, one above the packing and one half way up at the join.
The heat source will be a large propane burner.
I hope this makes some sense. I’m still very new to all this. Thanks for any advice.
design mockup
design mockup

rad14701
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Re: help with 3 inch stainless VM-LM design

Post by rad14701 » Thu May 19, 2011 6:54 am

Sounds like you have a decent grasp of what you want there, lucaman... However, there are a couple items that you might reconsider...

The packed column section only needs to be in the 48" (4') range even for a 3" column... I doubt that you would see increased performance by going higher and doing so may even start to degrade the performance... No need for the added overall height if there is no real benefit...

There wouldn't be much benefit in increasing the keg opening to 3" as has been proven many times by previous builders... A 2" to 3" tri-clamp adapter and two tri-clamps would allow for greater flexibility should you decide to build additional stills, and you know you will... But if you do decide to go with the 3" conversion then that would also work fine...

Aside from that, I'm not seeing anything jumping out as abnormal...

Manback
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Re: help with 3 inch stainless VM-LM design

Post by Manback » Thu May 19, 2011 7:07 pm

lucaman wrote:I want to start building my first still, and would love any advice, suggestions, concerns etc.
This might look a little extreme for a first build but I figure it might as well also be my last. My logic is there’s no point fucking around.

I want to make a 3 inch vm/lm combo. The build will be all stainless except for the top condenser and the packing, which will be copper, and the water lines which will be plastic. I’m using stainless because I can buy it cheap and have access to a good workshop to get all the work done easy. Also I like the lack of maintenance of stainless, and I’ve never really worked with copper much.
Why use stainless for the reflux condenser but not the product condenser? Agree on all counts re stainless. My copper is brazed in with oxy/acetylene
lucaman wrote: We will plasma cut a 3 inch hole in the top of the keg and weld on a 3 inch male connector.
The column, t piece and head will be 3 inch 316 grade stainless.

I will get 6 inches of 3 inch 309 grade stainless turned down to male and female thread. These will be cut into 1.5 inch lengths so that a male coupling can be tig welded to the top of each section and a female coupling to the bottoms. This way all sections can be separated for packing and cleaning. Also the head can be attached straight to the keg for a pot still or stripping runs, and the VM section can be left out if I don’t want to use it.
Why 309??

Also - if you take tube with a thickness of around 1.6mm, and chuck a thread in it.. well, most threads are gonna be a mm five, two mm deep.. tricky?? As opposed to welding on some triclamps :D that way you can angle whatever way you want, as well.. yes, we love triclamps here..
lucaman wrote: The colmn will separate into 2 pieces in the centre. Packed column length of maybe 1500mm (59 inches)?
59" is cool, as long as you have centering collar, BUT

Sounds like you are running gas. Allow 400mm for the gas setup, 500mm for the keg, 1500mm for the packed column,
400mm for the top bits.. you got yourself a 2.8m column.. how you gonna deal to the top of it?

Now, if you were to go for a 48" column, you're looking at 2.5, instead. Which is still fucking tall, but manageable - and the effect on take-off/purity/both will be pretty miniscule..
lucaman wrote: The take off line will be 309 grade stainless ¼ inch hydraulic line with a compression style screw on connector which can easily be moved from ball valve to needle valve as needed. I don’t think I will ever want to use both at once. This will have a liebig type condenser.
Again, 309??

And if it's all in SS.. will need to be a reasonable liebig, I'd go shotgun inside 2" if i was you. 80cm or so long, 4x 1/2" vapour tubes - gives you 3m or so of cooling. Stripping with (presumably) around 4kW and a weak little SS liebig will suuuuck.
lucaman wrote: For the VM take-off, 1 inch threaded pipe will be welded to the side to make a threaded T for the stainless ball valve. I know this sounds difficult but the right tools are there. Would I be better off with larger diameter, like 2 inch? Also, would this be best to come off horizontally or at an angle?
I'd go for 1.5" - 2". 2" if you aren't doing much in the way of head-pressure.
lucaman wrote: The head will be a typical Boka dual plate style with either a bought neddle valve or one made from a small stainless T piece using the motorbike spoke design. The top condenser will be the usual dual coiI type. I am not sure what diameter copper pipe to use for this nor what length I would need to make it.
If i were you, I'd tee up some 5/16, bang it around some 1" and then some 2". Leave about 3-4mm between each coil. and make it around 200 - 250mm tall to be on the safe side.
lucaman wrote: I will put the thermometer inlet below the bottom slanted plate.
I will put 2 centreing rings in the column, one above the packing and one half way up at the join.
The heat source will be a large propane burner.
I hope this makes some sense. I’m still very new to all this. Thanks for any advice.
design.jpg

lucaman
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Re: help with 3 inch stainless VM-LM design

Post by lucaman » Fri May 20, 2011 5:08 pm

Hey guys thanks for all the advice. :D
My reasoning for the 309 grade threaded fittings and tube is that the price is right. I can get them for free. The threaded adapters were to be turned down from heavier pipe, say 3 or 4mm so wall thickness was not such an issue.
And I was under the impression from some mates in the wine industry that the tri clamp connections were a little bit shit. But it seems I was wrong and they are hell affective and convenient for this application. So if I can get them cheap enough I will use them, but its hard to turn down free. I'm not too concerned about modifying the keg because I have a couple of them.
I was using copper for the product condenser because it has better heat co-efficient so I wouldnt need to use as much. But I will look into using stainless and going bigger. Again will come down to price.

As for the column length 4 foot works for me. I was unsure of how long was needed. The ratio vs fixed independant values arguement got tiring.
I'd go for 1.5" - 2". 2" if you aren't doing much in the way of head-pressure.
Yeah I will go 1.5" or 2" but Im not sure what you mean by head pressure. :?
And if it's all in SS.. will need to be a reasonable liebig, I'd go shotgun inside 2" if i was you. 80cm or so long, 4x 1/2" vapour tubes - gives you 3m or so of cooling.

I like that idea. I just need to look into how to split one line into 4.

Thanks again!

L

HookLine
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Re: help with 3 inch stainless VM-LM design

Post by HookLine » Fri May 20, 2011 5:20 pm

I'd go for a 2" take-off port, or larger.
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LWTCS
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Re: help with 3 inch stainless VM-LM design

Post by LWTCS » Fri May 20, 2011 5:23 pm

Off Topic,,,,,,,,,,,,,,,,,,,,

Hook

Back on topic now
Trample the injured and hurdle the dead.

nzl.james
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Re: help with 3 inch stainless VM-LM design

Post by nzl.james » Sun May 22, 2011 1:35 am

what your building is almost identical to what im half way through. if you look in "My still" section I posted a thread "help me finish my still". Im welding all the stainless up tomorrow and have a wash ready to go, so ill have results in a few days.
rather than plasma cutting the 3in hole in the top of the keg (which will probably leave splatter stuck to the inside), I took out the sanke valve thing, then hammered a piece of wood in the hole, which gave the holesaw something to drill into to centre it. makes a clean hole to weld a triclamp ferrule to.

Manback
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Re: help with 3 inch stainless VM-LM design

Post by Manback » Tue May 24, 2011 1:12 am

So ethanol vapor is heavier than air. Therefore, the greater the distance between your take-off and coil condenser, the greater the weight of the ethanol pushing down on the take-off. Basically, if the distance is bigger, you can have a smaller take-off arm and achieve the same rate.

Think about it with water. If you have a bucket of water, it will really gush out a hole in the bottom. If you have only a few ml left in the bottom, the flow will be much weaker. Same thing :)

If you can do 2" then that will be ample :)

lucaman
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Re: help with 3 inch stainless VM-LM design

Post by lucaman » Thu Jul 21, 2011 4:06 am

Hey all,

i dissapeared for a while but I'm back on track and have most of my stuff and will start to knock it all up tomorrow. The plan is as follows:
still design 4.jpg
I liked the shotgun condenser idea so I will do 5 or 6 10mm lines inside 2 inch, all stainless, 1200mm long.
I was going to put the shotgun condenser vertically, but at an angle it can be attached closer to the keg without hitting if required.
We managed to track down all materials in 318 stainless at good prices, all 1.6mm wall thinckness. Thats pretty thick walled for the 10mm lines in the shotgun consenser, hence the overkill dimentions.

Upped to 2 inch ball valve as per suggestions.

Bought full lengths of stuff to get the prices down, so we are making 3. A friend has claimed one, and we will have one left over to sell if anyone is interested.

For the valve we have a couple of sample taps for the wine industry laying around. I'll try this and if it doesn't give fine enough adjustment then Ill try something else. Given the low pressures and flow, the stainless needle valves are hard to justify just yet.
This is the tap: http://www.weware.com.au/productinfo.asp?ID=144" onclick="window.open(this.href);return false;" rel="nofollow It works much like the home made needle valves shown on this site, with a tapered bung that plugs a tapered hole as it is screwed in. I'll probably use it vertically as is shown in the picture with the treaded end down.

As for the boiler, I am unsure of how powerful I will need/ want. The 100k BTU burners are pretty overpriced at $150 but I'm worried the 3 ring 35000 BTU burners will be too slow to get boiling and maybe not pump enopugh heat to work my 3 inch still properly. Any recommendations?

i'll take plenty of pics as construction progresses.

Thanks for all the advice. :D

rad14701
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Re: help with 3 inch stainless VM-LM design

Post by rad14701 » Thu Jul 21, 2011 5:38 am

lucaman, that LM over VM combo still should serve you needs nicely... Keep us posted on your progress...

The high end of the heat input will only be for getting up to temperature and you will want fine grained adjustment capabilities on the low end for a reflux rig so don't get too carried away on the bigger is better mentality for the burner... You'd be better off having it take a few extra minutes to come to temperature if it means greater low flame control... No matter how much heat you throw at a keg it can only transfer heat into a mass of liquid at a given rate from the bottom so unless you implement a shroud you will merely be heating the atmosphere with any overkill heat... Heat smarter, not with brute force - kinda like the "work smarter, not harder" idiom... :idea:

lucaman
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Re: help with 3 inch stainless VM-LM design

Post by lucaman » Fri Jul 29, 2011 3:54 pm

We've made a start, and everything is turning out nicely.
1.JPG
The shotgun condensers look HUGE, at 1.2m long, and would knock the heat out of anything.
4.JPG
3.JPG

The TIG work is turrning out well. The pipe is blocked up and fully purged with argon gas during welding, to reduce oxidation reactions inside. Then is all pickled and cleaned up, with the insides ground flat so centring rings can be slid in. everything other than the copper mesh and the coil condenser is out of 316 grade stainless (maring grade), so they will stay nice for ever.
2.JPG
5.JPG
They will be around 2.5m tall when theyre all assembled and running, I'm going to need a chair.
It has all turned out fairly expensive and taken a lot of hours, but they should be great when they are finished. :D Then I wont have to keep using the puny still spirits thing.

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