Ultra Compact VM/LM/RLM Combo Head

[nitropowered]

In the past 2 weeks I researched a lot, I discovered the difference between VM, LM, RLM and about their PROs and CONs.. I wanted to design one head that supported all these 3 systems so I can try them all together. After some sketches and more researching I made a nice design but when I checked the price of all that fancy connectors, reductors, T-joints etc.. I simply realized that it's too expensive .

So, I was still determined in building my still and the only solution was to compress the amount of pieces needed to the smallest possible pool, this is what I got:

Compact Low Cost VM/LM/RLM Combo Head

VM mode = BallV adjusted, RefluxNV closed, TakeOffNV closed
LM mode = BallV closed, RefluxNV closed, TakeOffNV adjusted
RLM mode = BallV closed, RefluxNV adjusted, TakeOffNV open

Measures in mm.

The left outlet is for VM takeoff (planning to manufacture it myself because the 54x28x54 T fitting isn't so cheap and would be harder to cut and solder the slanted plates), ~1" tube + ball valve.
The two green things are needle valves (I had a lot of fun with CAD but I was too tired to finish it xD)
The condenser is a 11"x2" shotgun/graham hybrid (4 x 3/8" tube shotgun wrapped with a 3/8 coil), the 4 tubes are filled with Scrubber pieces, the top chamber too. (I understand that manufacturing and soldering in place the condenser will be a bit hard but I'm focusing on compactness and cheap overall price..)

Now I am interested about your expert opinion on my humble design, I would like to know if you guys think it will work? Let me know if there is any objection to this design. I am particularly interested about the condenser cooling capacity.. Do you think it will be enough for 1kw ~ 1.5kw?

[rad14701]

While the design looks fairly complicated and expensive to build, the only way to really determine whether it would function well is to put solder to copper... There are no blatant design flaws even though I see a few areas that may pose minor quirks, but I'll keep those to myself for now...

[nitropowered]

I agree on the complicated bit but why expensive? Anyway feel free to expose such incriminated areas xD.

Some additions:
The thermo port position is still WIP (position).
The plates had been drawn just for illustration (I am still going to study well the dimensions there)
Any measure can still change but the overall aspect is defined.

[LWTCS]

Really interesting.
Can you talk a bit more about the vapor path for the VM please?

[NcHooch]

Interesting ideas.
I gotta wonder if the LM might work better stacked on top of another 450mm of 54mm copper...with some scrubbies even
I like the VM setup tho.
Keep us updated

[Prairiepiss]

Really interesting.
Can you talk a bit more about the vapor path for the VM please?

Yes please.

[kiwistiller]

I suspect the rise on your VM takeoff will be your biggest challenge (in terms of maximum takeoff), that and the knockdown power (or lack thereof) of the vertical liebig. Nice thought process though.

[NcHooch]

Kiwi, the way I read it, VM uses the vapor column on the left which feeds into the graham portion of the combo condenser ... the shotgun portion of the combo condenser is for the LM & RLM .

Looks like it might be a little tricky to build but not impossible.

[Prairiepiss]

Ok am I missing something here? I thought I had the VM theory figured out. But this design goes against what I thought to be right. Here is the way I understood it? Please correct me if I'm wrong. I am trying to learn not discourage the op from this.

The way I thought a VM worked is this. It works on the principal that alcohol vapor is heavier then water vapor. This is why the VM takeoff came out and went down to the product condenser. The alcohol vapors being heavier would follow the lower path of the takeoff. The water vapors being lighter would rise past the takeoff to the reflux condenser condense and fall back down. The product condenser would then condense the vapors to a liquid causing a slight vacuum to draw more alcohol vapors into the takeoff.

With this being my understanding. How with this design will the heavier alcohol vapors follow a path upward to the product condenser? I think once it got primed and vapors started condensing it mite draw alcohol vapors up? But maybe at a lower percentage?

Don't get me wrong with this post. Like I said I'm just trying to learn. And I find this design pretty intriguing. Especially if my thinking of how a VM works is wrong.

[nitropowered]

Sorry guys I have some internet issues.. responding from phone at the moment. NcHooch got it right, the vapor rises and enters left tube going up to the graham condenser and then it comes back down to the outlet. About your theory Prairiepiss I think that the vapor never disjoints in two streams of vapor.. the only thing that happens is that vapor enrichens in alcohol every time it condenses and reboils in the packing, once it gets to the head you can only collect it or reflux it down the pipe. I 'm no expert too so maybe i'm wrong.. it is not drawn in the picture but all the vapor pipes should be isolated and this is only the head, under which lies 1.5m of packing. Another tweak i though is to close the top hole when the head is in vm mode so there is more pressure pushing thowards the vm exit (adding a pressure fitting on top for more security). Sorry for the bad english and the late answer xD keep the feedback and let me know if more clarifications are needed.

[LWTCS]

Yes insulating will be important on the VM riser. Think my question mark would be will the VM side under perform,,,,,,,,,or will any of thepeices under perform compared to comparable sized dedicated still heads............I does have a flair for the obvious doesn't I?

[Prairiepiss]

I will correct you on that. Do not block the atmosphere port. It is there for safety. Your reflux condenser should be knocking down all the vapors so there shouldn't be any pressure at the vent. If pressure build up occurs its a potential bomb. This much I know for sure.

[Prairiepiss]

And the reflux dripping through the packing is only part of the equation. If that is all it took then all reflux stills with packing would work perfectly and all would have the same purity output. Would they not?

[nitropowered]

Closing the port refers to VM mode... in VM mode vapor can exit through the graham condenser so it's not a closed chamber. I said about the pressure fitting in case I forgot to open the top in LM mode. The purity output of a still is based mainly on two things: packing height (and performance) and reflux ratio (dripping back liquid/ dripping out liquid). The only things I'm not sure of on this design are the cooling capacity of the condenser and the efficency of the VM takeoff valve, because the vapor has to go up for the length uf the condenser.

[Prairiepiss]

VM mode you will be adjusting takeoff with the VM takeoff valve that can and will close off the takeoff. So the atmosphere port needs to be open. That's why its in the design.

[myles]

I am slightly concerned with this and would like to see some vapour paths indicated.

You should never shut off all the vapour paths. If you are running in VM mode no vapour should be allowed to get past your condenser, if it does you are running in CM mode not VM and you absolutely need 1 vapour path left open. With a subsequent condenser in that path.

I think I can see what you intend with the slant plates and the external by-pass return into the column, BUT that line should never be fully closed. That should be the primary route for reflux condensate to get back into the column. Why would you ever want to shut it?

If you ever close it you have reverted to the basic slant plate design and reversed the improvement provided by the external bypass.

Give us a bit more detail of your intentions please.

[Bushman]

I must be missing something on this thread. My question is why would you need a combination VM, LM, RLM if the results for all 3 is to attain a neutral spirit? I can see a combination pot & reflux for different liquors.

[nitropowered]

Ok now with this picture I hope that will be clear that there is always a vapor path open

Vapor Paths

Now, the green line is graham condenser vapor path, the yellow line is the shotgun vapor path exiting on the top. It's also indicated the cooling water flow.

When in VM mode = 1 open, 2-3 closed, takeoff vapor going up and condensing through graham condenser and exiting down right, reflux vapor (yellow) going to shotgun condensing and falling onto plates then dripping back to packing because 3 and 2 are closed.

When in LM mode = 1-3 closed, 2 adjusted, vapor following yellow path condensing and then falling to plates, takeoff coming out from bottom right and reflux dripping from plate

When in RLM = 1 closed, 3 adjusted, 2 open, vapor doing the same thing as in LM mode going up condensing falling on plate and then spreading in reflux through pipe 3 and to takeoff through tube 2 to the bottom right.

What I supposed before, was to add a pressure fitting on the top of the shotgun near the vent hole and close the vent hole to help pushing vapor along the green path when in VM mode. The pressure fitting was only to have cautionary measures if i forgot to reopen the vent hole when passing back to LM/RLM mode.

I must be missing something on this thread. My question is why would you need a combination VM, LM, RLM if the results for all 3 is to attain a neutral spirit? I can see a combination pot & reflux for different liquors.

Well there is no need for that obviously but i wanted to create a combo head so I could test multiple procedures without having to fabricate 3 heads

Let me know if there is still any misunderstanding and let's concentrate on the two point of interest that I'm concerned about:

1) Do you think a combo condenser will be enough to condense the vapor streams (I can lengthen it if someone thinks its too short but I would preserve the width and aspect)

2) Do you think that the 3 separate modes this head is capable of would be at least efficient as the corresponding single mode variants. Simply said do you think this head ran in LM mode is at least efficent as a standard LM head (boka, nixon-stone offset head) same for VM and RLM.

[kiwistiller]

1) looks too short to me for total reflux - depends on your power input. Use the calculator on the parent site.

2) Define "efficient".

I still think the rise and restriction on the VM path would render it ineffective without some very careful balancing of backpressures by constriction of the reflux condenser vapour path, which is likely to be a pain in the arse to get right and safe.

[rad14701]

What happens when vales 1, 2, and 3 are closed...??? You've gotta account for the Darwin probability factor...

That combo head still needs to sit atop a packed column of appropriate height for proper reflux... Not required in the diagram, but required in practical application...

[nitropowered]

1) looks too short to me for total reflux - depends on your power input. Use the calculator on the parent site.

2) Define "efficient".

I still think the rise and restriction on the VM path would render it ineffective without some very careful balancing of backpressures by constriction of the reflux condenser vapour path, which is likely to be a pain in the arse to get right and safe.

Yep I had some doubts about the cooling capacity of the 27mm x 10mm 4 pipe shotgun.. Now that you mention it total reflux would be a little hard to achieve..
Do you think that using near 0 C water taken from a tub filled with ice and putting scrubber in the shotgun would help?

Damn i wish i can try all this things without having to throw away money and time xD

By efficient I meant "as good as". Seems like both of the points are against me..

What happens when vales 1, 2, and 3 are closed...??? You've gotta account for the Darwin probability factor...

That combo head still needs to sit atop a packed column of appropriate height for proper reflux... Not required in the diagram, but required in practical application...

if 1,2 and 3 are closed the vapor condenses follows the yellow path and exits the top vent hole... I mentioned before that it would sit over a 1.5m scrubber packed column

[rad14701]

if 1,2 and 3 are closed the vapor condenses follows the yellow path and exits the top vent hole... I mentioned before that it would sit over a 1.5m scrubber packed column

Yeah, I see the vent now that I've looked at the full-sized image...

Build it and report your findings... If nothing else, it'll keep you ot of trouble for a while and will also help hone your soldering skills...

[nitropowered]

Well seems that the design isn't really worth spending time on realizing it, maybe when I have more time and some material leftovers I'll give it a try.

[astronomical]

I'm curious about this type of design. The idea of running both LM and VM is better heads compression (LM at start and VM for remainder). Correct? So I pose the question, "Will RLM improve the heads compression any?". If not, is there any actual benefit over a basic LM/VM combo besides the fact that you could run just RLM and have an automatic RR change? The RR change on a RLM doesnt kick in until the hearts are nearing their end, right? If so, it wouldnt help much to run RLM and VM in a single run for the sake of "oops, switched take off valves at incorrect time". In the end, is two simple soldering points and an extra needle valve worth the $30 it would cost? One last question. If I did a run starting with LM and ending with VM would it be true that so long as I switched from LM to VM before any heads were apparent I would have nearly the same results as switching to VM directly after the heads? That question assumes that the benefits of switching from LM to VM are only noticed when tails come into play.

Back to the design at hand, why not just go the easy route of a T below a (Bok w/ return) with a VM arm ( I'd assume originality). If your design functioned well it would be cool but all that cool ingenuity would be "behind the scenes" unless you had glass around the condenser area.

Exuse any incorrect assumed "facts". I'm learning.

[rad14701]

astronomical, I'm with you on not spending the extra... I'd go with either LM or RLM, but not both... And as for which to use of the two it depends more on whether you want to primarily have control take off or reflux... The main advantage of RLM is that you are guaranteed a preset amount of reflux regardless of the take off rate... This should, theoretically, keep the packed column within equilibrium for a longer period of time before any adjustments are required... The flip side of that is that you have to be willing to watch the take off rate slow over the duration of the run...