Low cost LM/VM combohead

[Danespirit]

As i started on my new build (Compact potstillhead, a thread will follow), i got a few ideas comming into my mind. One of them is the idea of a LM/VM combohead.
While this may not be a new design, it's merely a combination of already known designs put together.
Design criteria: Easy to build, few parts and relativly cheap. Cheap is a keyword here, as this design also eliminates a costly valve.
I put a triclamp connection on the bottom, this of course would be optional for the builder and could reduce costs further if omitted.
First on,let me excuse for the bad drawing, my Autocad seems to have let me down here...so bare over with me.
Anyway, i am sure you all get the point when you look at it.
Materials: 2" stainless steel pipe , but of course copper would do as well...also it can be scaled up or down as you like.
This design with an angled condenserhousing will eliminate the need for a "roof" over the reducer. If one would choose to run it straight up and down, you would have to add this "roof" or solder a angled slant plate to the condensercoil. Otherwise your reflux would run straight down the column, passing the LM section.
So..ladies and gentlemen...join in for some constructive thoughts about this.

[humbledore]

Reminiscent of Manu's condenser controlled still, you'd have to put wire strips in the angled part of the column to make a space between coils and column wall. Otherwise there'd be pooling between the coils. And how do you get the reducer placed in the pipe? Other than that, interesting thinking.

[Danespirit]

Yes indeed.. Manu and DAD300 condenser controlled still influenced the design. As i wrote, it's not a new idea..just another combination for LM/VM.
One could make a kind of rail,the condenser could slide on it..wire strips would be a good choice.
If the column was made in stainless, you would simply weld the reducer on top of the downgoing pipe, and put another piece of 2" with a hole for the LM outlet on top of that. From there you only had to add the condensorhousing.
Edit: The hole for the LM outlet could be drilled or just grinded out at the bottom of the pipe by making a reversed U.

[DAD300]

Here's the manu LM version.

Liquid Management r.gif (4.1 KiB) Viewed 3400 times

Are you trying to keep it short?

Or to keep it inline...

It could all be done in triclamp with a 45 degree bend on top. If you use CSST for the reflux condenser it will allow the condensate to drain by.

But I suggest to keep them separate or one surly compromises the other, sometimes.

If you have the VM, there is also a way to put a "spoon" in it to be an LM. But it is not switchable during the run.

Look at Bigswedes post on his VM LM mixer.

[Danespirit]

Nice you are joining in DAD300..
I saw the idea of a "spoon" LM the other day..it's a interesting design. Though it should be very close to the refluxcoil in order to avoid splashing.
The point in using the angled design was to keep it simple and cheap. If one was to choose the straight up and down design,it would require a "roof"/hood over the reducer to keep the reflux from falling straight down the column.
Your CCVM with a LM slant plate solution is a very effective design, but would require a bit more work than a simple reducer on top of a pipe.
BTW..your 3" CCVM is beautiful.
Oh yes..of course i saw Big Swedes VM LM mixer..it's a piece of art, unfortunatly production equipment required to build like this is not at hand for anyone.
Almost forgot..for those who are reading and don't know Big Swedes build, here is the "Mix master": http://homedistiller.org/forum/viewtopi ... 17&t=48882

[HookLine]

Danespirit

1. VM port probably too close to the join between column and condenser housing, may not be able to get enough condenser on the column side of the port to condense everything in full reflux mode.

2. May not be enough vertical distance between condenser and VM port during take-off mode. That distance in a standard VM (typically 2-3") is a significant factor is helping vapour turn into the port and down the take-off path, due to slight but important differences in pressure. But not sure if that matters here. Experiment away!

Reminiscent of Manu's condenser controlled still, you'd have to put wire strips in the angled part of the column to make a space between coils and column wall.

May not be needed in this VM version. Reason for raising it in Manu's LM version is to keep the reflux condensate at the bottom centre of the condenser housing, so you can control the take-off ratio properly. But that doesn't matter here as the take-off port is off to the side of the condenser housing, not on the bottom of it.

I don't think condensate is going to back up much otherwise on the condenser coils. Worst case scenario is it gets to the same height as the diameter of the coil tubing, ie 1/4-3/8", before just spilling over and back down to the column.

[Danespirit]

Nice to see you joining in Hook..

1. VM port probably too close to the join between column and condenser housing, may not be able to get enough condenser on the column side of the port to condense everything in full reflux mode.

The design is intended to let the coil go all the way down and shield the VM takeoff, in order to get the column in total reflux.
Distance between the coil and VM port.. Yes i get your point there, i did not have that in mind, thanks for pointing out. You just gave me something to think about there..my currently VM setup has a distance of 50-60mm from the refluxcoil to the actual VM takeoff and runs fine there. Maybe a reduction to 40 or 30mm would be beneficial for my takeoff rate?
Assuming we had the right distance between the refluxcoil and VM takeoff in this design (moveable i know), does the diameter of the the takeoff branch have to match the column diameter (2") to get a even vapoursplit ? Would we disturb the laminar flow of the vapor by letting it pass the bend up to the refluxcoil, thus creating turbulent flow after the bend? At this point i am only thinking about the VM part of the column, as it would be the only part to worry about vapour flow.
I appreciate all the input from you guy's...

[DAD300]

The diameter of the takeoff in relation to the column is the minimum reflux ration. If you have a 2" column and a 2" takeoff you are theoretically 1:1. A 1" takeoff will be a minimum of approx 1 part takeoff for 3.6 parts reflux.

Achieving a minimum reflux ratio allows for max takeoff, (almost potstilling).

My idea is that turbulence and laminar can effect a dif, but minor at best.

[HookLine]

my currently VM setup has a distance of 50-60mm from the refluxcoil to the actual VM takeoff and runs fine there. Maybe a reduction to 40 or 30mm would be beneficial for my takeoff rate?

Increasing vertical distance between the take-off port and bottom of the reflux coil will help increase max take-off speed, due to small increase in pressure difference. I think some of the Swedes did some experiments on that stuff. But you can get the same effect by restricting the vapour flow into the reflux condenser section, above the take-off port. That is what i did on my bog standard 2" VM, added a 1" reducer on the bottom of the condenser coil.

Things are a bit different in a CC VM. But how much I don't know.

Assuming we had the right distance between the refluxcoil and VM takeoff in this design (moveable i know), does the diameter of the the takeoff branch have to match the column diameter (2") to get a even vapoursplit ? Would we disturb the laminar flow of the vapor by letting it pass the bend up to the refluxcoil, thus creating turbulent flow after the bend?

Like DAD said, the ratio of cross-sectional-areas of the take-off port and the entrance to the reflux condenser section is the most important thing.

But not the only thing. Turbulence helps vapour turn a corner more easily. You actually want to break up the laminar flow at the take-off port (or just before it).

[Danespirit]

Thank you DAD300 and Hookline..those explanations really gave me some good input.
If i ain't off building this VM head, it surely gave me some ideas for improving the one i already have..
I will implement this knowledge and improve my VM..
Thanks again, guys...

[Oatmeal]

This one would be real easy to incorporate. I just need a 3" 90. And a shotgun. That's all I need in this world...





And a dephlagamator