VM/LM questions

[Sam.]

Hi all, am starting to get serious about building my new still. Have decided to go with a 4" VM/LM combo. Have a few questions.

1. Is 1250mm about the standard height for the column?

2. Is the only reason of having reducers and restricting the flow at the take offs to direct more product to the VM part or could you make the whole length (including coil housing) 4"?

3. At what takeoff rate would you expect while pulling hearts?

4. Wheres the best place to buy needle valves?

5. Will liebig condensers be enough for spirit runs? (will be doing stripping runs in a pot still)

6. Gate valve or ball valve? (or is this just potatoe/potato)

All help will be very much appreciated.

P.S. If my mate can't hook me up with some 4" pipe might be able to buy some of yours 8-ball.

Cheers S&L

[MacStill]

I'm sure 5Star will chime in here, he's the VM guru on this forum ;)

Needle valves or any other type of valve is something mrs mac deals with on a daily basis, it's her job....... so if you want a good one PM her and she'll sort it out for you, it's all above board and sold direct at wholesale prices that we dont make any money out of.

Now! a 4" reflux still........... YEAH BABY! :dance: :dance: :dance:

[busman]

I'm no guru :violin: :text-lol: , but having done a lot of research before building my VM, if I were comtemplating a 4" build then my answers to those questions would be:

1) 1250 is about right for a 2". For a 4" I would make the packed section of the column at least 1500mm. If clearance was an issue then I would also use a "hammerhead" style condensor (ie. at a right angle to the column) so that I could get as much height on my column as possible without it hitting my ceiling.

2) You don't need a restrictor in the column at the takeoff, some have them, others have been built with just a hole bored into the side of the column for the takeoff branch, so yes you could just have a continuous 4" section from end to end. You'll also save a shitload of money by not having to buy any 4" reducers.

3) One of them piece-of-string questions there :lol: . Most peoples 2" will pull an easy 1.2L/hr, up to 2-2.5L/hr max (if you're careful), 5Star's 3" pulls 5L/hr if I'm not mistaken. 4"? Who knows? 8? 10? A lot! :lol:

4) Mrs Mac :lol:

5) You're going to be condensing a lot of vapour with a 4" column - you'll either want a pretty serious liebig, or a shotgun (and if you went with the hammerhead reflux condensor at the top of the column, I'd make that a shotgun as well)

6) They both have their pro's and con's, a gate valve allows finer adjustment, I use a ball valve because I like that you can see how far open it is at a glance.

My $0.02.

Cheers

busman

oh yeah, and

4" reflux still........... YEAH BABY! :dance: :dance: :dance:

lol, we're the loonies of the hobby-distilling world over here aren't we? :laughing-rolling:

[R-sole]

Use the design calculators here to calculate your column height.

http://homedistiller.org/reflux_calc.htm
http://homedistiller.org/refluxdesign.htm#hetp

I can't get it to aezeotrope now matter how i play with it.
1400mm column at 4000w seems to be a sweetspot at 95.2%

Have you thought about what type of packing and how much of it you'll need and costed that out? :shifty:

I would be looking at a shotgun product condensor or a triple wall liebig.

[Sam.]

Thanks for the info guys.

I think I will try for the 4" all the way through if I can so I don't need to use the reducers for ease and cost.

For the column height because I am using gas it is hard to input a power, I just assumed longer is better (ie more refluxing) and that 1250 was a minimum standard?

For the needle valves will have to chat to Mrs, McStill it seems.

For the condenser I was thinking of a shotgun. Just to confirm that the shotgun has the one off take splitting into several then all of them running through a big jacket? (like a multi-liebig?)

Also having the diameter this big I guess centering rings will be a necessitity. Would I just use 3" - 2" reducers with three packed in the column? (Bottom, middle, top)?

S&L

[MacStill]

I was reading something the other day on HD about large diameter reflux column packing that made me think.

It was along the lines of SS scrubbers compressing a little under the weight of all the distillate (reflux) once the column was trying to equalize, and the problems it would cause.

If your column was 1500 long you could fit 13 plates in it, this would be enough to get 95% but would be a lot of work, the up side would be that you have permanent packing that would never need replacing.

[Sam.]

Forgot to put on the last post, I have three large packs of copper mesh that I bought from the Amphora Society for the packing.

I guess the weight of the spirit could be an issue, will need to check after the first run I guess! :D

[Kimbo]

It was along the lines of SS scrubbers compressing a little under the weight of all the distillate

Yeah Mine compressed a bit in my 2.5" column, but i feel it made it better ;)
once i open up the LM valve, i can pretty much walk away from it.
it will give me a consistent 96% till it slows down to stuff all when it hits the tails.

[R-sole]

Forgot to put on the last post, I have three large packs of copper mesh that I bought from the Amphora Society for the packing.

I guess the weight of the spirit could be an issue, will need to check after the first run I guess! :D

Best you open one of those packs and roll a piece of mesh up enough to fit in a piece of 4".
Weigh one or two or six of em and add up how much you'll need to pack the column.


I believe you're in for a shock. :(

[8-ball]

if you buy the 4" pipe from me ill do it by the half meter since you probably don't want 2m of it
i think 5Star said you can only post in 1.1m max lengths

[Sam.]

If I do buy it, it might be for the lot because if this build is a success I reckon my mate will want one as well ;)

[crozdog]

What are you going to pack it with?? copper mesh? spp? marbles?

I believe there are issues when going above 3" with ensuring you get even packing.... hence why plates tend to be more effective with bigger diameter columns.

[Sam.]

It will be packed with the structured copper mesh from the amphora society

http://www.amphora-society.com/Structur ... d_p_6.html

I bought 6 pounds and with my calculation should pack about 1.215m (4.5ft) of 4" so should be enough.

Seeming this stuff is prerolled getting it uniform shouldn't be a problem.

The problem I am beginning to worry about is the distillate compacting it, wonder if I could attach the centering rings to the column to hold the packing in place as well? The only issue then would be I won't be able to take the packing out once in, but I will only be using it for reflux purposes not stripping.

[busman]

You'll still want to take it out every couple of runs to clean it and fluff it out. By the third run in my 2" VM my copper mesh had compacted to the point that it caused the column to flood.

[R-sole]

You need to be able to take the packing out.

This is what it looks like after 4 runs.

packing1.jpg

You have seriously underestimated how much packing you need. I suggest you get a piece, roll it to fit in a piece of 4 inch pipe (104mm roll) so it's tight as you can roll it.
Then unroll it an d measure the length per roll.

X that by the length of column you need.



Not trying to knock you, just trying to save you from a mistake. :crazy:

[Sam.]

Holy shit that is a lot of packing!

I didn't realise it needed to be packed that tight, can you get away with having it a bit looser? or will this just cause it to compress more? or will you increase the theoretical plate height way too much?

Once you have cleaned that, does it look brand new again?

[MacStill]

Holy shit that is a lot of packing!

and I'm pretty sure that's from a 3" column ;)

What size boiler you plan on using?

[Sam.]

Was thinking of starting with a 50L keg boiler but I guess a lot bigger would be better for 4", maybe I am just dreaming and should start off with a 3" :(

[R-sole]

That's from a 3" column. Yes you can clean it by soaking in a 10% acid solutiona nd then neutralising with a 10% alkaline solution.

Comes up like this....

packing2.jpg

Really, i mean really...open your packing and roll it up tight as you can to a 104mm roll....

These are 80mm rolls and hold over 5m of mesh per roll.

Thats 110 metres....

[busman]

maybe I am just dreaming and should start off with a 3" :(

I would say build it once, build it right, and build it as big as the budget will stretch. If you have the money, the tools and the time to build a 4", then build a 4". If you build a 3" (which will still be at considerable expense) when you know you could have done a 4", you may never be happy with it. Just expect everything to cost more the bigger it gets and you'll be fine, don't skimp on the amount of packing or the height of the column to save a few bucks if you don't need to, and remember your still is going to serve you for a great many years and save you many times its own cost to build in the long run.

:shock: Gawd I sound like an old fart don't I? :laughing-rolling: