VM, CM, and LM confusion

[BW Redneck]

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.



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.



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!



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.

Edit: okay, going to try to clean those drawings up a bit.

[Froggy]

Very useful. Thanks

[manu de hanoi]

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

[erbachem]

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.

[Oaty]

Got me again I need to get somebody to take this bell from around my neck.

[lliw]

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

[Husker]

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.

[rad14701]

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...???

[Husker]

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

H.

[stillvodka]

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

[rad14701]

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]

Correct Rad, PDA1 is LM. I confirmed that with Ian last fall.

[stillvodka]

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.

[countryboy]

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]

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

[jgrimm]

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]

As the poster above,

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

[Pierre L'Ivrogne]

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

[VPOWER]

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..... PM me if your interested

[Bushman]

As the poster above,

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

Aqua vitae I thought the translation worked well, also it is another good example explaining the differences.

[jorel]

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

[Samohon]

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...

[Brendan]

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]

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?

[Samohon]

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...

[oakback]

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]

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.

[oakback]

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]

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

[myles]

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.