VM, CM, and LM confusion

Vapor, Liquid or Cooling Management. Flutes, plates, etc.

Moderator: Site Moderator

BW Redneck
Trainee
Posts: 775
Joined: Sun Dec 10, 2006 11:57 am
Location: 1000 acre farm, Ohio

VM, CM, and LM confusion

Post by BW Redneck » Wed Feb 20, 2008 5:28 pm

Alright, now I know and have observered that newbies are a bit confused by the above abbreviations because they are rarely, if not never, mentioned on the home site. Unless you've had it explained to you by a regular here, or have read and understood The Compleat Distiller, you're pretty much lost.

They are all abbreviations used by us to differentiate between the different means of controlling reflux in a column still. I have already explained them here, but I know that a picture truly speaks a thousand words, and have since decided to make a few simple diagrams to aid in this.

Disclaimer: these are very crude, thrown together on ms. paint. Shaky wrists don't exactly help.
:roll:

Image

This is one of the simplest designs to understand and build. A single condenser condenses all of the vapor and returns part of the condensate back to the column via a valve that can handle small quantities (needle valve). The valve can expand and contract with temperature changes and small changes in the valve setting can have a large impact on the reflux ratio. This kind of offset design, the Bok inline, and the "valved reflux" all follow this general layout and design.

Image

This is the second most common, but the least controllable designs out there. The reflux ratio is controlled entirely by controlling the amount of water running through the condensers. If you recirculate water, then the gradual increase in temperature will slowly reduce the reflux ratio, requiring constant attention. If your water supply is limited in your area, then this is NOT the design for you!

Image

This is one of the least common designs out there, but one of the most easily controllable. The valve controlls the vapor and directs it between two separate condensers, and since the amount of ethanol in vapor form is many times greater in volume thean the liquid, coarse adjustments in valve opening make a rather fine adjustment. Changes in temperature have little effect on the reflux ratio for this same reason. They remain pretty constant, and with a little bit of trial and error, predictable valve settings can be acheived (example: 1/2 turn may change the ratio by 2%, etc.)

Hoped it'd be of some use. :D :roll:

Edit: okay, going to try to clean those drawings up a bit.
Last edited by BW Redneck on Wed Feb 20, 2008 8:09 pm, edited 2 times in total.
"If you can't dazzle them with brilliance... baffle them with bullshit."
"Don't steal. The government hates competition."
"Believe none of what you hear, and only half of what you see"

20lt small pot still, working on keg

Froggy
Swill Maker
Posts: 245
Joined: Mon Nov 06, 2006 1:30 am
Location: South East Oz

Post by Froggy » Wed Feb 20, 2008 5:35 pm

Very useful. Thanks
Here froggy froggy..
Shane

Our reading material:
The Compleat Distiller
Making Pure Corn Whiskey

manu de hanoi
Site Donor
Site Donor
Posts: 778
Joined: Mon Aug 13, 2007 9:06 am

Post by manu de hanoi » Fri Mar 07, 2008 5:22 am

nice drawings too at :
http://www.bryggforum.nu/viewtopic.php?p=53037" onclick="window.open(this.href);return false;" rel="nofollow

erbachem
Novice
Posts: 75
Joined: Tue Oct 03, 2006 7:01 pm
Location: New Zealand

Post by erbachem » Tue Mar 11, 2008 6:16 pm

First time I've truly understood VM. Thanks a lot. Gives me an idea of what I am going to do with the bit of 2 inch pipe I have lying aroung at the moment.
ME

Oaty
Swill Maker
Posts: 446
Joined: Thu Mar 27, 2008 8:42 am

Re: VM, CM, and LM confusion

Post by Oaty » Thu Aug 07, 2008 5:11 am

Got me again :oops: I need to get somebody to take this bell from around my neck.
Never refuse to do a kindness unless the act would work great injury to yourself, and never refuse to take a drink-- under any circumstances.
- Mark Twain's Notebook

lliw
Novice
Posts: 14
Joined: Mon Dec 22, 2008 10:04 pm

Re: VM, CM, and LM confusion

Post by lliw » Tue Mar 17, 2009 3:44 am

I assume the still spirits super reflux still is just a cooling management still?

User avatar
Husker
Admin
Posts: 5031
Joined: Thu Aug 17, 2006 1:04 pm

Re: VM, CM, and LM confusion

Post by Husker » Tue Mar 17, 2009 4:35 am

lliw wrote:I assume the still spirits super reflux still is just a cooling management still?
Yes it is. The only thing super about it the is marketing dept selling it.

H.
Hillbilly Rebel: Unless you are one of the people on this site who are legalling distilling, keep a low profile, don't tell, don't sell.

rad14701
Master Distiller
Posts: 20866
Joined: Wed Dec 19, 2007 4:46 pm
Location: New York, USA

Re: VM, CM, and LM confusion

Post by rad14701 » Tue Mar 17, 2009 6:18 am

Some spiffy CAD drawings would be just the ticket... Did I read somewhere that someone was going to try to make some for the Wiki...??? If so, links to them would work great... Your images do get the point across, however, BW Redneck... I'm sure they'll help folks get their head around the different concepts...

Where's the image of that "scurge" Super Reflux design...??? :roll:

User avatar
Husker
Admin
Posts: 5031
Joined: Thu Aug 17, 2006 1:04 pm

Re: VM, CM, and LM confusion

Post by Husker » Tue Mar 17, 2009 6:23 am

Note, as drawn, it appears that the coil input/output lines in your pix are reversed.

H.
Hillbilly Rebel: Unless you are one of the people on this site who are legalling distilling, keep a low profile, don't tell, don't sell.

stillvodka
Site Donor
Site Donor
Posts: 431
Joined: Sun Apr 23, 2006 10:13 am

Re: VM, CM, and LM confusion

Post by stillvodka » Wed Mar 18, 2009 11:23 am

What would you say the Amphora PDA1 is LM or VM ? did it need a product cooler/condenser in the take off ?

rad14701
Master Distiller
Posts: 20866
Joined: Wed Dec 19, 2007 4:46 pm
Location: New York, USA

Re: VM, CM, and LM confusion

Post by rad14701 » Wed Mar 18, 2009 12:22 pm

stillvodka wrote:What would you say the Amphora PDA1 is LM or VM ? did it need a product cooler/condenser in the take off ?
Pretty sure the PDA1 is a LM column... Top condenser is for reflux and product condenser is to further reduce the still hot spirits coming out the take off port...

astrangebrew
Novice
Posts: 97
Joined: Sun Oct 26, 2008 11:34 am
Location: Lurking - north of the border

Re: VM, CM, and LM confusion

Post by astrangebrew » Wed Mar 18, 2009 2:56 pm

Correct Rad, PDA1 is LM. I confirmed that with Ian last fall.
Time flies like an arrow
Fruit flies like a banana
Groucho

stillvodka
Site Donor
Site Donor
Posts: 431
Joined: Sun Apr 23, 2006 10:13 am

Re: VM, CM, and LM confusion

Post by stillvodka » Wed Mar 18, 2009 10:49 pm

I am just near finishing building something similar to the Amphora still, but with a cross flow condenser and with 3'' SS COLUMN, when I had my PDA1 I came to the conclusion it didn't need a product cooler, it didn't do much really, so I have left it out on this one, all that's left to do really is to connect to the boiler and give it a good clean up and polish, the Brass fittings to that column was quite difficult to do, they look a bit grubby but will clean up, problem was the heat was being pull out the joint so made it hard to silver solder, their alright though, just don't look professional I will have to do a bit with the file get um smooth. :)
Image
Image
Image

countryboy
Novice
Posts: 2
Joined: Sun May 24, 2009 6:09 pm

Re: VM, CM, and LM confusion

Post by countryboy » Sun May 24, 2009 8:16 pm

hi guys,need plans for a 3 inch reflux column with a crossflow condenser , i saw some plans earlier on, but i can't find them again , any help will be greatly appreciated, links would be great thanks , countryboy :

breeze
Novice
Posts: 21
Joined: Sun Aug 16, 2009 12:21 pm

Re: VM, CM, and LM confusion

Post by breeze » Wed Aug 19, 2009 10:47 am

just what i needed. i assume best thermomiter position would be near as possible to the point where vapor crosses over? thanks

jgrimm
Novice
Posts: 14
Joined: Fri Dec 04, 2009 9:46 am

Re: VM, CM, and LM confusion

Post by jgrimm » Fri Dec 25, 2009 5:07 pm

I know this post is a bit old, but I ran the Swedish forum page that was posted earlier in the thread through google translate. Not trying to rudely bump, but just thought if anyone else is researching still types it may be helpful to do so.

-Jt

Here is the link to the translated page:
http://translate.google.com/translate?h ... Fp%3D53037" onclick="window.open(this.href);return false;" rel="nofollow

aqua vitae
Swill Maker
Posts: 223
Joined: Fri Jan 22, 2010 3:29 pm
Location: Thou Ancient, Thou Free

Re: VM, CM, and LM confusion

Post by aqua vitae » Sun Jan 16, 2011 5:50 am

As the poster above,
jgrimm wrote:I know this post is a bit old
..but here is another translation from the same site with more pics.
http://translate.google.com/translate?h ... Ft%3D12350" onclick="window.open(this.href);return false;" rel="nofollow
The translation doesn't work well though so don't bother trying to read :lol:

Pierre L'Ivrogne
Novice
Posts: 19
Joined: Sun Oct 07, 2007 8:46 am
Location: Paris, France

Re: VM, CM, and LM confusion

Post by Pierre L'Ivrogne » Fri Jan 21, 2011 4:11 am

Thanks a lot for this post, at last I understand what it stands for.

VPOWER
Novice
Posts: 5
Joined: Thu Sep 29, 2011 10:07 pm

Re: VM, CM, and LM confusion

Post by VPOWER » Mon Oct 03, 2011 9:01 pm

i might be able to help with the drawings.... i can easily cad them up.... i might not know my distilling but i know my cad..... :D PM me if your interested

User avatar
Bushman
Global moderator
Posts: 15031
Joined: Tue Mar 30, 2010 5:29 am
Location: Pacific Northwest

Re: VM, CM, and LM confusion

Post by Bushman » Mon Oct 03, 2011 11:34 pm

aqua vitae wrote:As the poster above,
jgrimm wrote:I know this post is a bit old
..but here is another translation from the same site with more pics.
http://translate.google.com/translate?h ... Ft%3D12350" onclick="window.open(this.href);return false;" rel="nofollow
The translation doesn't work well though so don't bother trying to read :lol:
Aqua vitae I thought the translation worked well, also it is another good example explaining the differences.

jorel
Novice
Posts: 2
Joined: Fri Nov 04, 2011 6:37 pm

Re: VM, CM, and LM confusion

Post by jorel » Fri Nov 04, 2011 7:58 pm

I'm a complete newbie, and I thought this was VERY helpful. thanks!

Samohon
Master Distiller
Posts: 3432
Joined: Mon Oct 05, 2009 4:22 am
Location: Somewhere in the UK...

Re: VM, CM, and LM confusion

Post by Samohon » Sat Nov 05, 2011 6:16 am

jorel wrote:I'm a complete newbie, and I thought this was VERY helpful. thanks!
Head on over to the Welcome Center..., Click on New Topic.. and tell us a little about yourself.
Whats your tastes, still design, if any, etc; etc...

Welcome aboard...
♦♦ Samohon ♦♦

Beginners should visit The New Distillers Reading Lounge and the Safety and Related Issues among others...

User avatar
Brendan
Rumrunner
Posts: 671
Joined: Sun Nov 20, 2011 2:07 am
Location: Australia

Re: VM, CM, and LM confusion

Post by Brendan » Mon Nov 21, 2011 1:31 am

That was very useful, thanks for that!

I knew what the letters ment, but never properly understood the controllability of each type.

Important information to weigh up when considering designs...

Propaniac
Novice
Posts: 26
Joined: Fri Aug 10, 2012 7:55 am

Re: VM, CM, and LM confusion

Post by Propaniac » Sun Aug 12, 2012 3:29 pm

I saw your diagram and I like it a lot. I was thinking maybe it would be a good idea to add slanted plates under the condenser on the VM setup. What do you think?
Bokakob - VM Still.jpg

Samohon
Master Distiller
Posts: 3432
Joined: Mon Oct 05, 2009 4:22 am
Location: Somewhere in the UK...

Re: VM, CM, and LM confusion

Post by Samohon » Sun Aug 12, 2012 4:50 pm

Propaniac wrote:I was thinking maybe it would be a good idea to add slanted plates under the condenser on the VM setup. What do you think?
That would be an LM/VM combo. A few members are running these stills including myself.
The Boka LM keeps the VM clear of heads when collecting product (neutral)... Great rig...
♦♦ Samohon ♦♦

Beginners should visit The New Distillers Reading Lounge and the Safety and Related Issues among others...

oakback
Novice
Posts: 97
Joined: Mon Mar 09, 2009 4:59 am
Location: Florida, USA

Re: VM, CM, and LM confusion

Post by oakback » Thu Aug 16, 2012 10:43 am

Samohon wrote:
Propaniac wrote:I was thinking maybe it would be a good idea to add slanted plates under the condenser on the VM setup. What do you think?
That would be an LM/VM combo. A few members are running these stills including myself.
The Boka LM keeps the VM clear of heads when collecting product (neutral)... Great rig...
I still consider myself a newbie, but I've been using my 2" boka quite a bit. What do you mean by this? On some of the finer points I'm left wondering, because most instructions or methods I read about online are pot still-related. I've often wondered that if I can control the temp and the reflux ratio, where the heads actually are (if I'm collecting at 174F/78.8C), and how much I need to throw out.

Prairiepiss
Master Distiller
Posts: 16355
Joined: Sat Dec 18, 2010 7:42 am
Location: Heatland Prairie USA

Re: VM, CM, and LM confusion

Post by Prairiepiss » Thu Aug 16, 2012 11:37 am

oakback wrote:
Samohon wrote:
Propaniac wrote:I was thinking maybe it would be a good idea to add slanted plates under the condenser on the VM setup. What do you think?
That would be an LM/VM combo. A few members are running these stills including myself.
The Boka LM keeps the VM clear of heads when collecting product (neutral)... Great rig...
I still consider myself a newbie, but I've been using my 2" boka quite a bit. What do you mean by this? On some of the finer points I'm left wondering, because most instructions or methods I read about online are pot still-related. I've often wondered that if I can control the temp and the reflux ratio, where the heads actually are (if I'm collecting at 174F/78.8C), and how much I need to throw out.
The fores and heads are taken off through the LM take off. WK they never go through the VM takeoff. So when you take the hearts off through the VM takeoff they are not tainted by the fores and or heads. An LM head can compress the fores and heads better then a VM. But the VM can take off a cleaner heart section and compress the tails better. So the two working together in the same still. Make a better product. Your getting the best of both stills.
It'snotsocoldnow.

Advice For newbies by a newbie.
CM Still Mods
My Stuffs
Fu Man

Mr. Piss
That's Princess Piss to the haters.

oakback
Novice
Posts: 97
Joined: Mon Mar 09, 2009 4:59 am
Location: Florida, USA

Re: VM, CM, and LM confusion

Post by oakback » Fri Aug 17, 2012 9:02 am

Prairiepiss wrote:
oakback wrote:
Samohon wrote:
Propaniac wrote:I was thinking maybe it would be a good idea to add slanted plates under the condenser on the VM setup. What do you think?
That would be an LM/VM combo. A few members are running these stills including myself.
The Boka LM keeps the VM clear of heads when collecting product (neutral)... Great rig...
I still consider myself a newbie, but I've been using my 2" boka quite a bit. What do you mean by this? On some of the finer points I'm left wondering, because most instructions or methods I read about online are pot still-related. I've often wondered that if I can control the temp and the reflux ratio, where the heads actually are (if I'm collecting at 174F/78.8C), and how much I need to throw out.
The fores and heads are taken off through the LM take off. WK they never go through the VM takeoff. So when you take the hearts off through the VM takeoff they are not tainted by the fores and or heads. An LM head can compress the fores and heads better then a VM. But the VM can take off a cleaner heart section and compress the tails better. So the two working together in the same still. Make a better product. Your getting the best of both stills.
Thanks, that clarifies it perfectly.

Greg1234
Novice
Posts: 21
Joined: Mon Oct 15, 2012 4:03 pm

Re: VM, CM, and LM confusion

Post by Greg1234 » Tue Oct 30, 2012 8:17 am

What is the difference in take off rates between CM and VM ?

myles
Site Donor
Site Donor
Posts: 2451
Joined: Wed Oct 15, 2008 11:34 am
Location: UK, in the heather

Re: VM, CM, and LM confusion

Post by myles » Tue Oct 30, 2012 8:31 am

Greg1234 wrote:What is the difference in take off rates between CM and VM ?
Probably not a lot in normal use, after all they are really just reconfigured variations of the same thing. The difference would come if you were to switch off the reflux condenser and run like a pot still.

You can do that with a CM but you can not really (without closing off the reflux condenser air vent) do that on a VM.

If you had a CM still and a VM still with all the major dimensions the same and both reflux condensers removing the same amount of energy, the volume of product and collection rates would be the same.

Post Reply