"45* Offset LM"

[bunny]

Has anyone spent any time with the "45* Offset LM"?
A drawing is available below in Hook's collection (Thank You Sir!) on page 16.

Still Drawings-10.pdf

(2.08 MiB) Downloaded 199 times

I have made an armful of different heads for the 1 inch ID tubing I have been using.

One change I have made and continue to use is the elimination of the reflux return tube.
I believe if your running close to the "aqueous" state (or not) with some liquid supported above or
close to the top of your packing it doesn't matter exactly where your reflux lands. I have not noticed
any difference with or without the return tube.

I'm also experimenting with the location of the take-off tube.
Currently, I have moved it up the condenser tube. This seems to help in 3 ways: 1) The condensate
is a little cooler if the take-off tube is closer to the actual condenser. 2)The take-off tube is further
away from the main column making collection easier. 3) The reflux gets to travel a longer distance
touching the hot pipe before it reaches the packing.

The picture of yesterday's run shows about 8 inches contact in it's journey back down the column.

This design is very simple with just a valved take-off tube and one perpendicular low head dam.
If anyone is using something like this, I would like to hear about it.

bunny

[Setsumi]

So it is a LM head that use a Liebig as reflux management. My consern would be the effectivenes of the Liebig to maintain 100% reflux... although it is probably not necessary in all settings. AND it seems you run a small diameter column, myself find larger diameter columns easier to run due to lower vapour spead. Although I understand that access and availability to larger diameter tube is not always a given.

I agree with you that RLM is probably not necessary, although initially it was introduced to keep the reflux ratio in LM higher through out the run. But once a run slows down you probably are past energy efficient recovery of alc.

What packing do you use? And what lenght is your column? What is your abv and take off speed?

Last, what is your opinion on LM vs VM? Myself currently runs CCVM but there are many discussions that promote LM.

[bunny]

So it is a LM head that use a Liebig as reflux management.

Well it is in toto LM. But really it's valve and power management to control reflux. You can use whatever you want to knock the vapor down. Look at the pics and you will see a couple liebigs, a couple outer wrapped coils and an air cooled variety.


My consern would be the effectivenes of the Liebig to maintain 100% reflux... although it is probably not necessary in all settings. AND it seems you run a small diameter column, myself find larger diameter columns easier to run due to lower vapour spead. Although I understand that access and availability to larger diameter tube is not always a given.

Everything I have shown is able to to due 100% reflux up to column flooding +. Vapor speed is easy to control if you know your true amperage, voltage, and element resistance.

I agree with you that RLM is probably not necessary, although initially it was introduced to keep the reflux ratio in LM higher through out the run. But once a run slows down you probably are past energy efficient recovery of alc.

My runs usually don't slow down as the take-off rate remains constant through most of the run. When I get a small (5-10*) spike in my lower thermometer I shut down.

What packing do you use? And what lenght is your column? What is your abv and take off speed?

I use Manu's SPP at 48" packed. My abv is somewhere around 96.5 temp corrected.
Take-off speed: anywhere from 125ml/hr to a very comfortable 300ml/hr. I operate
from 14-20ips vapor speed, 5.00-6.00A (TRMS)


1" plumbing is not for the "GO FAST" crowd but I can make some really fine neutral.


Last, what is your opinion on LM vs VM? Myself currently runs CCVM but there are many discussions that promote LM.

Since neutral is my only desire, LM is really the only choice for me. With LM I can easily set my reflux ratio and be on my way. I have tried VM and wasn't that impressed. You don't want to know what I think about CCVM.

[Oatmeal]

Now I think I would to hear more about your thoughts on ccvm....

But mostly just appreciate the peek into your distilling universe!

[drmiller100]

I run them in my continuous stills. Collecting the liquid caused me headaches so I have tried a dam, fittings.

[HiroP]

Your 45 degree design is very similar to the I built a year ago and am really enjoying using.

With mine I there are two parts - the top condensing head - a straight 1 1/2" copper pipe about 14 " long (thin coiled copper inside for cooling/condensing) which is above a 'liquid management' piece (1 1/2" tube) about 10" vertical and then 45 degrees and 4 " tube that contains an interior slot plate and output tube in the 4" section - like the one on page 16 and yours, but I have added 'tee' fitting on the outlet pipe and two needle valves- one for collecting and one for returning/refluxing back into the the 10 " vertical pipe. I use a 6" piece of silicone tubing to connect the output pipe (2") to the "tee" fitting - this acts as a 'sight glass'. Two pieces connect with clover tri clamps.

I find I have very fine control when refluxing- I can compress heads nicely at low temp and can rebalance the column (36" x 1 1/2" copper tube and stainless steel scrubbies) at the end to extend hearts collection. Keeping a 3" column of distiliate in the clear tubing I pull around 50% collect and 50% back into reflux at the beginning and end of the run and 80/20% collect/reflux in the center of hearts.

On a reflux run of sugar wash after heads I now can get mostly 90 -95 abv and stop collecting at 80 abv. Towards the end of the run I need to stop collecting at 50/50 and rebalance the column (100 % reflux for 10 minutes) about 3 times (temp rises = column out of balance) and lower the boilers' electric element wattage to stabilize the temp and continue collecting hearts (90-85 abv).

I have not considered controlling the temp of the distillate in all this. I insulate every thing as much as I can and try to keep the take off distillate as hot and stable as possible (I run my condenser cooling water as slow as possible) as i am reinjecting back into the column as I need to. I also have a secondary cooling coil that chills the collected distillate before dripping into my jars.

I have also combined the condenser coil cap (a standard 1 1/2 copper cap) to have the 'vent' tube (6") in reflux mode and that becomes the collecting spout when reconfiguring to stripping runs and condensing piece angled down at 45 degrees off the top of my still lid. (Then I cool the coil as much as possible).

The 45 degree off the column works really well for me, glad to see your setup is similar.

[drmiller100]

Pro tip.
I put my needle valve on the reflux side, amd collect overflow.
The reflux rate is a requirement to match the heat source amd is constant across the run or across multiple runs

The product rate slows down all on its own as the wash is stripped of its ethanol. This means you never have to adjust the needle valve, even across different alcohol percentages unless you change your heat source.

I do have a bypass with valve to go full reflux on startup

[fzbwfk9r]

is using silicone tubing acceptable in the hot 95%Eth area?

[zed255]

For the water lines it is...

[bunny]

This is my most recent venture with the 45* LM head.
My previous testing pointed me to a 2" rig with 1500 watt x 120 volt element without a controller.
Further testing with a 10% abv solution I was able to collect 94mls/min. (5640mls/hr)
If I take off 500ml/hr this gives me a RR of 10 to 1.

This is a very easy build with minimal soldering, less than a typical LM design.

[bunny]

more pics:

[MereCashmere]

Now I’m real eager to hear your thoughts on CCVM

[Metalking00]

Whats the benefit of the 45* offset? Just easy to make? Or is there something else i dont see?

[Iulistoi]

I think 10:1 is a huge reflux rate. I can achieve 95% ABV with as low as 2:1 RR. Maybe 4:1 is high enough for the most exigent tastes and it can bring 96% ABV throughout the hearts run.

10:1 reflux rate would give a few hundreds mililiters of spirit per hour at a power of 2000W on a 2 inch column. Extremely booring. I think it's an unnecessary waste of power and cooling water. Most senses don't feel any difference between 95 and 96% ABV. I can taste the difference between 93 and 94 but higher than that is almost the same.

For a perfect neutral, I strip run with the column with low reflux ratio to 90% ABV mean strength. I dilute to 30% and run again for the spirit run, keeping the RR higher this time, at about 2:1. Cutting enough heads and tails is another big factor for a good neutral heart spirit.

[squigglefunk]

so I have this condenser that came with my crappy chinese still, it's a stainless steel thing with a coiled CSST stainless line inside it.

Could I repurpose this thing for a LM head ... I would be adding the tube (prob 1/4" copper) and needle valve there is a corner there where the liquid would naturally pool. Am I understanding this right , does it seem like this would work in theory?

[still_stirrin]

… there is a corner there where the liquid would naturally pool. Am I understanding this right, does it seem like this would work in theory?

In theory, yes.

But, I’d recommend calculating or better yet, measuring the liquid hold up in the corner of the “condenser can”. To do this, close the LM valve and orient the can in the position it will be when attached to the column. Then, pour water into the upper vent hole until water spills out back through the vapor inlet. Then, you can pour the water collected inside the condenser into a measuring cup. That will be the volume of condensate pooled in the condenser. Remember, the greater the condensate pool the greater your smearing will be through the run. In a sense, it is an “integrator” of the fractions as they condense.

One issue that I have with these 45* angle designs for LM reflux heads is that the condensate that spills over the weir (the plate as bunny has installed, or the spill over to the vapor inlet as you’ve proposed) is that the condensate will wick back down the tube wall as it flows back to the column (and packing). For reflux to be efficiently effective, the falling condensate needs to interact with the rising hot vapors to transfer the heat from the vapors back into the condensate, creating a reboil of the volatile constituents.

The 45* angle almost ensures the condensate will flow back along the wall of the column. The Boka design (slant plates) has the weir spillover falling back into the center of the column via the notched tab in the lower plate. This helps with the interaction between condensate and vapor.
ss

[bunny]

Now I’m real eager to hear your thoughts on CCVM

My thoughts about CCVM are mine and not to be shared.
If you have some interest in what I have been doing for two years in this hole, please join in.

Whats the benefit of the 45* offset? Just easy to make? Or is there something else i dont see?

It is easy to make and just as easy to run. You may gain a little overhead clearance, but not a lot.
I'm running this with a 1500w x 120v element without a controller. Full control is by the take-off rate alone.
The only concern is the RC needs to be able to knock down every thing sent up the column during 100% reflux.

I think 10:1 is a huge reflux rate. I can achieve 95% ABV with as low as 2:1 RR. Maybe 4:1 is high enough for the most exigent tastes and it can bring 96% ABV throughout the hearts run.

10:1 reflux rate would give a few hundreds mililiters of spirit per hour at a power of 2000W on a 2 inch column. Extremely booring. I think it's an unnecessary waste of power and cooling water. Most senses don't feel any difference between 95 and 96% ABV. I can taste the difference between 93 and 94 but higher than that is almost the same.

For a perfect neutral, I strip run with the column with low reflux ratio to 90% ABV mean strength. I dilute to 30% and run again for the spirit run, keeping the RR higher this time, at about 2:1. Cutting enough heads and tails is another big factor for a good neutral heart spirit.

Some of us have higher goals when it comes to neutral. I have tried to exceed "Canadian Snowflake Vodka". I believe I have at least equalled it and maybe reached further north to "Santa's Reindeer Teardrops".
You're perfectly welcome to drink whatever you like.

so I have this condenser that came with my crappy chinese still, it's a stainless steel thing with a coiled CSST stainless line inside it.

Could I repurpose this thing for a LM head ... I would be adding the tube (prob 1/4" copper) and needle valve there is a corner there where the liquid would naturally pool. Am I understanding this right , does it seem like this would work in theory?

LM_module.gif

Why yes, I think that could work.
I would swap hot and cold water entry/exit.

I also disagree wholeheartedly with SS about pooling.
All of your reflux will pass through that area continuously flushing it out.
Smearing is not likely.

I also disagree about the reflux running down the walls of the column being any kind of a problem at all.
The reflux runs down over the weir, most of it keeps going and hits the scrubby topper and that's where the separations begin. In addition running down the hot wall reheats the reflux before it hits the scrubby topper. I have not noticed ANY performance difference whether the reflux was centered or just ran down the wall.

[squigglefunk]

Why yes, I think that could work.
I would swap hot and cold water entry/exit.

I also disagree wholeheartedly with SS about pooling.
All of your reflux will pass through that area continuously flushing it out.
Smearing is not likely.

I also disagree about the reflux running down the walls of the column being any kind of a problem at all.
The reflux runs down over the weir, most of it keeps going and hits the scrubby topper and that's where the separations begin. In addition running down the hot wall reheats the reflux before it hits the scrubby topper. I have not noticed ANY performance difference whether the reflux was centered or just ran down the wall.

thank ye kindly for giving me your thoughts, I have been trying to figure out something to do with this weird condenser ....

and I am thirsty for reindeer tears now

[Oatmeal]

I'd settle for a sip of Canadian snowflakes....my neutrals are probably comparable to American pond water...

Wasn't it concluded that condensate wicks back into the packing, making things like centering rings unnecessary?

Anyways, it's cool to see the offset LM put into practice!

[squigglefunk]

I'd settle for a sip of Canadian snowflakes....my neutrals are probably comparable to American pond water...

my first attempt at neutral might be closer to pond scum... subtle mildew notes with a light bouquet of chlorophyll

[squigglefunk]

Wasn't it concluded that condensate wicks back into the packing, making things like centering rings unnecessary?

pretty sure I read that in one of my eye bleeding reading sessions

[zapata]

I do not think that has been concluded. It certainly hasn't in the scientific and industrial literature. It has always been known to be less of a problem the smaller diameter the column and the higher the abv. Centering of initial reflux return is probably irrelevant where a layer of liquid or froth exists at the top of the packing as many advocate for SPP.

[drmiller100]

Wasn't it concluded that condensate wicks back into the packing, making things like centering rings unnecessary?

Yes. Within 4 inches of a marble packed column Temps followed the typical gradient with normal losses from the column sides creating a dome of Temps at each vertical level.

[Oatmeal]

Let's try "concluded" as more of a hive mind conclusion at home distiller-.

Nice point zapata, that makes a lot of sense (I'm easily swayed by most arguments

And, interesting drmiller- that description is beyond my basic understanding, but I'll fake it till I make it!

[zapata]

Yes. Within 4 inches of a marble packed column Temps followed the typical gradient with normal losses from the column sides creating a dome of Temps at each vertical level.

I'm having a hard time unpacking that. Could you try to rephrase it or share a relevant link?

[drmiller100]

Yes. Within 4 inches of a marble packed column Temps followed the typical gradient with normal losses from the column sides creating a dome of Temps at each vertical level.

I'm having a hard time unpacking that. Could you try to rephrase it or share a relevant link?

I missed this. Sorry.
I use marbles In a column. I tried returning the reflux fluid down the column in the middle or just putting a fitting on the edge.
It didn't Matter much.

Within 4 inches down into the packing the Temps were equal across the packing meaning the reflux fluid spread evenly.

In most columns the column outside runs cooler than the center unless you insulate well.

I'm not describing it well.

[StillerBoy]

Within 4 inches down into the packing the Temps were equal across the packing meaning the reflux fluid spread evenly.

How were you able to determine, that the temp at the 4" mark from the top of the packing, was equal across the packing ? ? plus what was size of column are you referring that activity occurs ? ? and what size of marbles are you referring to ? ?

Within 4 inches of a marble packed column Temps followed the typical gradient with normal losses from the column sides creating a dome of Temps at each vertical level.

How were you able to arrive at this conclusion, based on the statement above, by instruments, observations or just your thoughts ? ? a definition of what "each vertical level" mean and how that what was determined would help in understanding ? ?

My views on vapor movement within packing differs..

Mars

[drmiller100]

Within 4 inches down into the packing the Temps were equal across the packing meaning the reflux fluid spread evenly.

How were you able to determine, that the temp at the 4" mark from the top of the packing, was equal across the packing ? ? plus what was size of column are you referring that activity occurs ? ? and what size of marbles are you referring to ? ?

Within 4 inches of a marble packed column Temps followed the typical gradient with normal losses from the column sides creating a dome of Temps at each vertical level.

How were you able to arrive at this conclusion, based on the statement above, by instruments, observations or just your thoughts ? ? a definition of what "each vertical level" mean and how that what was determined would help in understanding ? ?

My views on vapor movement within packing differs..

Mars

I measured with a temp probe. Pretty east to do.
36 inch tall 13 mm marbles

Marbles are pretty consistent. There is some heat loss through the walls so at any given height the edges are a bit cooler than the center