VM spirit run, neutral

[casper the Irish]

I just followed Hooks design, the two exits are to be equal and 1 third column diameter. And it was reminiscent of Rad's and others I'd seen with for some reason that "waist" or narrow section in the middle. This vertical condenser tees from 2" and back up to 2" thru a short 3/4" exit. I made it like Rad's with a wee reservoir and inner tee to gather liquid below the coil - his boka design there to have the best of both worlds. Also can be capped without coil for potstill.

It was one of Hookline's 20 drawings and his comment seemed to suggest it was theoretical, worth building so wanting to explore ideas and it looked within my skills and understanding if not as elegant as Dads CCVM that's what I made.

What volume are you getting when you go above 90%? The 3" boka is dramatically more volume than the 2"VM, it's shorter at 48" high and starts about 93% before the slide. Whereas the VM sticks at 89 from start to end... so far

I shall use the stepladder and add 12" to the column, see if that makes a difference!

[humbledore]

The diameter of the column relates to throughput, speed of product coming out. The height affects ABV. If you are getting 93% on a 48" column and 89% on a 70 inch column there's something definitely wrong. 70" is more than enough to get you to azeo in any standard 2" column. And that 89% was running low wines, not wash. I am running out of advice for you, maybe someone else will step in. there must be something wrong with the design. I would spend some time looking at more tried and true builds, sorry!

And I'm familiar with the concentric cup collection area but that's for a boka. If you are not taking off from that collection cup you just have extra reflux in there to smear unless I'm not understanding something.

[DAD300]

From the picture...the reflux coil is in the center of a horizontal? More pics please...

[casper the Irish]

I have only run the 2" VM at 54" so far (say 60" from top of keg)


The coil inside a 2" pipe attaches here. I can cap it to use in potstill mode. The horizontal is 9" so the condenser sits about 6" from the bend/ top of column

[casper the Irish]

[still_stirrin]

Casper,

A couple of things I note about your rig:

1) the VM valve is below the horizontal portion, making it susceptable to flooding, especially with packing in the horizontal portion. That flooding means you can't really run it as a VM, but rather as a LM (you're regulating the liquid takeoff rate) with the rest of the liquid smearing the upcoming vapors. Removing the horizontal section packing might help reduce the smearing too.

2) your reflux condenser is operating as a CM head, causing the upcoming vapors to regulate by the condensing rate. In this case, the horizontal section's packing helps to stabilize the reflux. But remember, it causes smearing in your design.

3) your minimum reflux ratio is set by the boiler rise diameter and your reflux condenser's diameter and/or your VM takeoff diameter (the Tee's, if you will). Since your column has centering rings (which I'd doubt really help you much) also restrict the vapor flow, causing expansion and condensation, they too affect the reflux ratio.

You've obviously got a lot of things working in your still, some good, some not so good. Smearing seems to be the biggest problem (as I see it). I'd move the "so-called" VM valve back up to the centerline of the horizontal section and reduce the length of pipe between the valve and your reducing Tee. Then, I'd eliminate the packing in the horizontal section. Next, I'd remove the centering rings from your column (to increase the vapor upflow rate. Let your column packing and the reflux condenser to their jobs.

I agree with the other posters here that your column height should get you easily to 190proof. You may need to turn your boiler heat down a bit once you establish reflux equilibrium. But then your VM valve should work properly for your takeoff.

I hope my oratory has some benefit for you. In the end, its all about how you run it. Good luck.
ss

[casper the Irish]

Offset VM

Thanks ss. Valve now inline close to outtake. Packing removed. One of three rings removed, two centring rings are 1" inside 2" so maybe not so restricting? 1 at top before bend, other 18" off the bottom near keg.

I began this post worried that I was indeed getting LM when the valve was cracked just open in reflux. Leaving valve open I wondered what the reflux ratio might be, was there reflux built in by the reducer ratio at outtake or did I need the valve at all (apart from full refluxing). I then found I needed to adjust the gas, thus heat management. Now you observe CM and smearing. This design seems to be not so elegant after all and I want to get this done right, as well as elegantly simple if possible.
I can make a new head for this column. Where should I look now, what do you recommend as the latest thinking on VM stills? Dads ccvm perhaps....

This was Hooks drawing, and this is what I have built.
In it he argues: "consider the idea of preferentially directing vapor flow directly toward takeoff valve in a VM instead of at the reflux condenser.
If we combine this idea (swept tee) with Manbacks vapour flow experiment we get this:"

Hook's drawing

Offset VM restricted, vertical condenser

I am also working with a 3" bokakob, my first still, so for the MkII I really wanted a simple design VM that featured the latest thinking among the experts. After months of study on here I thought Hooks seemed "cutting edge" as well as simple to make... but what do I know? And I think I am having as much fun working the copper as I wait for the endless 30l fermentations to gather enough low wines.

PS
The new valve position allows it to be removed eg for potstill, or, to insert a vapour gin basket as below. Can any gin head tell me if this is necessary or would a bag of herbs dropped in with the column packing is better (refluxing the herbs)

Gin basket?

[still_stirrin]

You might need a liquid drain on your gin basket if vapor condenses in it prior to full heat. Otherwise, I think it's much better.

And I can appreciate the valve-on/valve-off modularity too. It's kinda' like mine except my VM valve is 1" (25mm) and my concentric reflux condenser is vertically located above the column (so liquid spillover drops directly back down the column.

I believe (seriously) that you'll see an improvement with the neutral purity. I can get 190proof out of mine and its only 39" (1m) of marble packed column.

But I do like the simplicity of VM operation for high %ABV spirits. It packs it all in there: reflux equilibrium then open the VM valve a bit (I do about 1/2 open giving me a reflux ratio of 16 = (2/.5)^2) to 1. Runs steady until you hit the tails and the vapor takeoff all but stops. Open the valve wide open and bring the heat up a bit and drive it hard to get the rest of the tails for feints.
ss

[still_stirrin]

For your question regarding placement of the gin basket, Odin's the expert. But I've read his comments on placement and he often recommends they be put into the boiler, as in a tea basket hanging in the boiler. Column mounted baskets would do the same thing too, I'd suspect.

Jimbo also has made gins/gineevers too. Perhaps he'll chime in here too. If not, send him a PM, he'll answer you.

Although a design engineer, I'm not experienced at making gin (yet) although interested in the process and designs.
ss

[skow69]

Hookline used the smaller throat for the RC in an attempt to reduce the minimum reflux ratio. All things being equal, a junction will cause a vapor stream to split in proportion to the size of the pipes, so two 3/4 inch legs result in a minimum RR of 50%. This is a common feature of many VM designs. There is no magic in making them 1/3 the column diameter, except maybe to increase vapor speed or turbulence.

On a related note, VM discussions often debate the inertial effect of rising vapor barreling past the takeoff arm and lunging headlong into the RC. Hook's notes indicate he was hoping to benefit from the inertia of the vapor by sweeping to the horizontal and connecting the RC at 90*.

As you said, it was a conceptual design. That makes your still the proof-of-concept model, so now we can start to evaluate some of these ideas. [Actually, I think you altered the design significantly by replacing the sweep with a 90* ell and extending the horizontal section. Hook didn't want to make it difficult for the reflux to get to the column, he just wanted to nudge the vapor to the left a little.]

At any rate, I think we have sufficient reason to conclude that any advantages of this sort of condenser offset are quickly overcome by the difficulties of dealing with the side effects and unintended consequences. If it was me, I would lose the ell, rotate the tee, and restrict the RC throat to the same size as the product takeoff. Replace the ball valve with a gate valve, install it as close to the tee as possible, and take out the centering rings.

I just think you have beat your head against the wall long enough.

Skol
skow

[DAD300]

I will admit I couldn't make any sense of the design until I saw the drawing.

The reflux condenser is in an indirect vapor path!

a. it is probably producing very little reflux, unless in 100% reflux, valve closed.
b. if the column and horizontal branch are not ABSOLUTELY positioned, vertical and Perpendicular or aligned to make the reflux transfer back to the column...the whole horizontal will pool until it overflows back to the column. As skow69 said, "Actually, I think you altered the design significantly by replacing the sweep with a 90* ell and extending the horizontal section." So, if you tilt the column off vertical, to make the reflux drain correctly, you also ruin the columns vapor path.

I agree, you have beat your head long enough. You have all the parts and pieces to make an inline VM (column, "T", Reflux Condenser,...). If this was an effort to reduce the height, changing it to an inline design will make it so much more efficient that you won't need the height you loose.

Now, I'm glad for the post. Shows people are experimenting. Bob had a lot of Boka Designs he never built also...

[HookLine]

Hey, one of my crazy ideas finally gets put to the real world test. As all ideas should be. Thank you, casper.

On a related note, VM discussions often debate the inertial effect of rising vapor barreling past the takeoff arm and lunging headlong into the RC. Hook's notes indicate he was hoping to benefit from the inertia of the vapor by sweeping to the horizontal and connecting the RC at 90º.

Yup.

The basic point of this design idea was to see if it would help lower the minimum reflux ratio (for a given column : takeoff port ratio), by using the vapour momentum to force it past the reflux condenser port a bit more, especially when the valve is wide open.

I disagree with Dad300 that "it is probably producing very little reflux, unless in 100% reflux, valve closed". No doubt it will change the response curve for the valve setting (which is kinda the point), so you will need to adapt to that, but otherwise I think it will work on the same lines as any VM.

But that is what experiments are for, to see which idiot is right!

Further comments:

1. having a reducer at the output end of the horizontal section not only helps balance the column : takeoff port ratio, but also prevents reflux condensate flowing down the output path,

2. place the valve immediately after the reducer, like in the drawing, [EDIT: just noticed you already have discussed that change],

3. raise the output end of the horizontal section slightly (before soldering in), so it is angled slightly upwards and the condensate will more easily flow back to the column, like some have done with the tube-and-shell condenser design popularised by Harry (search for "Jackson Crossflow Condenser"), usually enough play in fittings to allow that,

4. keep the horizontal section as short as practically possible (without being obsessive about it), and keep the reflux port nearer the output end (i.e. after the vapour has finished the 90º turn to horizontal),

5. easy enough to add LM, either by inserting a small dam near the column end of the horizontal section, or setting up the reflux condenser shell as a liquid trap, like some of Bokakob's designs (and I have done a drawing or two showing how to do that with this design idea),

6. make sure the reflux is returned to near the centre of the packing (at the top).

Looking forward to hearing how it all works.

Cheers

[phillmystill]

By deep do you mean on a VM when the drizzle slows to drops, needs more heat and not much reflux... That's where I got to as the temp rose to 97°C and ABV 85%. Even tho my column is 2" the output slowed to 5 drops/sec collecting those fusels. Good to know there's better stuff to come.

Do I dump the fusels? -For rums, are the fusels part of rum oils, to be kept and recycled as feints, or do they preceded the good oils?

And can I assume y'all do stripping runs first?

This experience has helped me make it simpler. My new pot still for stripping runs is a 36l SS cooking pot. Some SS car exhaust pipe welded on the lid, fasteners spot welded and plastic water pipe to act as a sealing gasket.

Hi Casper, following this thread with interest. I do however feel the need to challenge the statement highlighted in red.

Plastics (apart from ptfe) are not considered safe to have in a hot alcohol vapour environment; they can contain undesirable chemicals that could leach into your product.

People on here generally use ptfe tape or flour paste to seal things up.

[skow69]

Hey, one of my crazy ideas finally gets put to the real world test. As all ideas should be. Thank you, casper.
.
.
.
Cheers

'bout time you showed up.

[casper the Irish]

Oh good to hear from you Hookline. That's what I am puzzling right now, to understand the effect that condensate "raining" into the horizontal vapour path is doing to the output flow. It does appear to supercool it I was measuring 75°C at the reducer port. Would the flow not also be turbulated, I did wonder if with the RC moved tight to the bend I should keep some inches after the rainstorm to let the flow gather and settle before exit. I suppose I am asking why BOTH exits need to be close together, what effect the horizontal has on the outtake, and especially if I just switched the RC away to the bend but kept that 9" lyne arm?

4. I can take out all pipe and reduce the lyne arm to max4" which is the length of the 2" tee. In fact I could cut the tee by an inch or two. So if I make the horizontal short as possible which side of the tee do I trim most. You say keep my bend close, but my reducers closer?

3 & 6 I will tweak this angle although I have over an inch pooling depth in the horizontal so flooding is unlikely. I could also tweak the 2" at the bend for a bit of incline? I have a centring ring under the bend, which by the way is the best sweep bend I could find. So you would keep the two, maybe three centring rings as drawn, or just the top one?
Yes I liked the LM mod in your drawing and I did that too, saw it first in Rad's. I have a removeable 1" equal tee cut to fit there, allows about an ounce to gather when fitted. Is that enough, Rad seems to require 3oz or 4 oz

Regarding my wee potstill seal I have PTFE liquid tape sheet or tube and silicone foam. None helps seal a flexing lid I know the debate on plastic seals I did read the pva and brass lead caveats but can't otherwise find a flexible gasket thick enough. Ptfe tube is too hard to squeeze as a gasket. But I'm counting on the lid rim has a reveal which may hide the tubing from gasses inside. I don't do spirit runs on the potstill it's only 8% and reducing wash in that pot with only escaping steam in contact.

[myles]

There are so many advantages to the offset condenser VM design that I would not consider building any other VM design. The ONLY justification for the inline version is that it is cheaper and easier to build. For me that is a poor reason to build it.
My choice is a combined VM and LM.

You should insulate the entire vapour path upto the VM valve. Keep it hot and there is NO condensate above the VM valve. I like a horizontal condenser to save space, but you can use a vertical one.
Here is another one with a shell and tube reflux condenser. Before the insulation was put on.

[myles]

The minimum reflux ratio you can achieve on a VM is determined by the cross sectional areas of the two vapour paths when the VM valve is wide open.
These are the vapour path into the reflux condenser chamber and the vapour path into the product branch. Closing the VM valve increases the reflux ratio and returns more reflux to the column.
You can now build proportinal valve VM heads, but I am not convinced that you actually need one.

[casper the Irish]

What are those offset advantages Myles. I was asking why the RC and outtake need to be close since Hooks design asks for the shortest possible horizontal, then I see your two vapour paths seem to be as far apart as possible, so what is happening at the tee. If steam is light and ethanol is heavy why would paths separate better at a horizontal tee. I can see the advantage for LM but not for VM

You might see (photo above) my extended insulation up to the valve.

[skow69]

In the words of Eric Clapton, "HangonHangonHangonHangonHangon!"

Casper -- the still heads that Myles is talking about have no relation to the hookline design you have been working on. The fluid dynamics are totally different. Don't try to equate the challenges of one to the characteristics of the other or you'll be headed back down the rabbit hole. Look at the top of the column where your vapor hangs a hard left. Myles' splits to opposite directions. Then your vapor rolls down the hall to chose a fate. Exactly 50% of Myles' heads for the exit. The other 50% condenses and takes the express shute back to an explicitly designed location to enter the packing. Meanwhile most of your vapor condensed into a puddle defined by a bell reducer and the tolerance of the level you used to plumb the column.

That's oversimplified, of course, but you get the idea right? Apples and oranges. I am a big fan of the style Myles shows. It would be a good alternative to your design, but it is not a tweak, it is a tabla rasa reset.

why the RC and outtake need to be close

they don't.

so what is happening at the tee

vapor splits

If steam is light and ethanol is heavy why would paths separate better at a horizontal tee.

They won't. The streams will be homogeneous and identical, same as your still, composition determined by vapor pressures of the components, Rault's Law, and all that shit. See Parent Site/Theory.

Don't work so hard at making it hard.

[casper the Irish]

I don't know how these things work, I just see copper and ask why, begin to work at it until I understand it. I have found that until I build, the range of opinion and theory here is a bit overwhelming and for a newbie not easy to discern older ideas from innovation, all spoken with authority (but maybe wrong) and often is really hard to understand... So I build and learn as I go. To keep learning I need to keep building. It all starts too complicated until I work hard to make it simple. And there are so many rabbit holes on here to explore!

Can you refer me to any diagram that explains Myles head. I see the VM gate valve is not horizontal yet mine must be.
If vapour splits at the tee only half gets refluxed, but, I like the way this outflow is kept dry, not rained on by condensate at the split.
I also like the LM return from his RC. Is liquid injected into the column upward or downward? I imagine the tube ends above packing but I can't see a nonreturn trap in the second pic.

I was reading Harry talking about flow and turbulence for example.
Harry argues this bypass liquid return can be used to suppress smearing of a VM. I've a boka cup at my condenser so could direct liquids directly from there into the column packing instead of falling into the flow to puddle. This will keep my ethanol flow dry instead of turbulated and wetted by condensate. Might be just what this design needs to make it work, and like Myles rig would keep the flows separate, ethanol flow dry and therefore purer, with wet condensate completely bypassing the bend returned directly into column packing.
Worth a try?

[skow69]

Hi Casper,

I am pretty disappointed in the quality of our communication, but you seem to be genuinely trying and I respect that. So I will try as long as you do.

I will try to answer your questions in a very literal manner and we'll see how that goes.

Can you refer me to any diagram that explains Myles head.
I will look.

I see the VM gate valve is not horizontal yet mine must be.
Myles head could be off level by 10 to 20 degrees with no noticeable effect on operation. A variation of 1 or 2 degrees on your horizontal section could totally destabilize the column by either depriving it of reflux or draining the lake. Moreover, a large pool/any pool of liquid reflux that isn't serving a specific and very important purpose is a really bad idea and should be avoided at any cost. I really think this should be intuitively obvious.

If vapour splits at the tee only half gets refluxed,
Half gets refluxed if the VM valve is full open. As the valve closes, more is refluxed and the reflux ratio increases.The valve is used to reduce the CMA of that branch.

but, I like the way this outflow is kept dry, not rained on by condensate at the split.
I also like the LM return from his RC. Is liquid injected into the column upward or downward? I imagine the tube ends above packing but I can't see a nonreturn trap in the second pic.
Opinions and designs vary on this. Below is a pic of mine looking up from below. It is intended to deliver reflux to the center of the packing.

I was reading Harry talking about flow and turbulence for example.
Harry argues this bypass liquid return can be used to suppress smearing of a VM. I've a boka cup at my condenser so could direct liquids directly from there into the column packing instead of falling into the flow to puddle. This will keep my ethanol flow dry instead of turbulated and wetted by condensate. Might be just what this design needs to make it work, and like Myles rig would keep the flows separate, ethanol flow dry and therefore purer, with wet condensate completely bypassing the bend returned directly into column packing.
Worth a try?

If you can make the plumbing work, sure, go for it. But wouldn't it be easier to move the condenser to the other side of the column?

[casper the Irish]

There's no problem with your communication, getting this quality of advice is a privilege. Just requires a lot of study and head scratching for me to clamber up there with you guys making sense.

To move the condenser other side means swapping the ell for a tee? I will have a go at that for rig Mk3. Looks like it's possible to still indoors no high ceilings, great! I have neighbours watching so I have to still outdoors at night when the moon don't shine.
But that would be a new head and not least for Hookline's sake I want for a while to stick with this idea from Manback and see if Harry has an answer to this smearing, pooling and washing (wetting and cooling) of outtake at the RC.

Harry proposed a return by-pass for "heads-trapping", with a valve to bleed off the heads. Why not return ALL the reflux liquids to the column by this route. It's an easy modification. I read that turbulence is needed to separate the streams. This bypass idea returns all RC liquids to the column just above the packing AND does turbulence splitting before the ell well away from takeoff port. No puddle. If puddle or wet copper is sticky, absorbent to pollutants, this bypass will keep the flow into the bend dry right past the RC thru to the valve.

Will post pics next week when I have more low wines ready for a second run.

[skow69]

There's no problem with your communication, getting this quality of advice is a privilege. Just requires a lot of study and head scratching for me to clamber up there with you guys making sense.

To move the condenser other side means swapping the ell for a tee?
Yes it would. As in the style of those Myles heads above, or mine for that matter.

I will have a go at that for rig Mk3. Looks like it's possible to still indoors no high ceilings, great! I have neighbours watching so I have to still outdoors at night when the moon don't shine.
But that would be a new head and not least for Hookline's sake I want for a while to stick with this idea from Manback and see if Harry has an answer to this smearing (washing of outtake by condensate too near the valve).
Harry is the man! And he won't blow smoke up your skirt. Can I assume you are familiar with his tastylime library, then?

Harry proposed a return by-pass for "heads-trapping", with a valve to bleed off the heads. Why not return ALL the reflux liquids to the column by this route.
That's exactly what both of Myles' photos show: a full time unvalved dedicated reflux return tube from the condenser to the top of the packing. I think it's a great idea. Mine does the same thing. I'll post a pic below.

It's an easy modification. I read that turbulence is needed to separate the streams.
I don't understand that phrase. Please clarify.

This returns all RC liquids to the column just above the packing AND does it before the ell well away from takeoff port. No puddle. If puddle or wet copper is sticky, absorbent to pollutants, this bypass will keep the flow into the bend dry right thru to the valve.

Must it still be shortened?
You mean your horizontal tube? As long as you can keep the reflux out of it and make sure that nothing collects in it, that should take care of the big problems, so, theoretically, I suppose you could make it as long or short as you like. I would keep in mind, however, that it is a potential source of random effects that may not have been considered in the original design, like variations in the temperature gradient or flow characteristics. And that potential increases with more length.

I had found a way to use that lyne arm to counterbalance the leibig so the weight actually helps keep the column vertical but I'll shorten it, not sure why now so I am asking. Not a big deal, just trying to understand why before I do it.

I originally built this as a traditional inline VM. Then I read how LM is supposed to be really good at compressing heads and reconfigured into this. It's a bit of folly, too, as I just really like the symmetry and the curlyque vapor trap. The original reflux return line was 1/4 inch. I changed it to 3/8 when I found it couldn't handle the volume. It protrudes through the left fitting and turns down at the centerline in an attempt to optimize the reflux delivery location. The heads trap holds less than a half ounce. I wanted to keep it small to minimize smearing. All of the condensed reflux drains into the trap. Anything that isn't removed through the needle valve is then sent to the column above the packing.

[thepatchworkdoll]

http://www.dropbox.com/s/a28s7fac4x6cxt ... 3.JPG?dl=0" onclick="window.open(this.href);return false;" rel="nofollow
What about this VM Proportional Splitting Head that I use as my avatar. I built it under Harry's guidance and it serves me very well.
Your work looks good Skow but what happens if you forget one day and both valves are shut at the same time. Is there an out for the pressure build up. On my valve configuration it is impossible to have a closed still. When one valve is shut the other is open and vice versa. That's where the Proportional part comes into play. Hope this helps.
Regards
Patch

[humbledore]

I imagine that is why the valve handle is taken off. Patchwork are those to valve handles soldered together? I assume opening one closes the other?

[thepatchworkdoll]

Hi Humbledore your correct. They are welded together. One in the open position and one in the closed position. When one opens the other shuts. Very simple but extremely effective.
regards
Patch

[skow69]

Hey patch, how ya been? I have admired that clever device of yours ever since you broke it out a couple years ago on the other side of the hill. Every time see it I want to tee up a football and kick for three. I hope that some day you will donate it to Notre Dame and they will display it with Touchdown Jesus.

My LM valve is on the other side of the trap, so the return line vents to the atmosphere. Maximum pressure should be about 3 inches of water column or 0.1 psi. Funny thing though, I ran that through prototype testing and haven't touched it since except for cleaning runs when I like to steam blast the liebig. Turned out it just didn't add any functionality to a real run on that still. So it goes. I'm glad I built it and found out. How do you like yours? Do you use the 0 RR position a lot?

[skow69]

The Heavenly Host is going wild as the SON OF GOD signals the go-ahead score. From the opposite bench the Prince of Darkness skulks into the locker room to design his evil deceptions for the 2nd half.

[thepatchworkdoll]

Ha Ha Ha Skow
Thats magic man I like it a lot. Speak to you later
Patch

[skow69]

I got a football jones and it's only February.