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Re: VM head variations

Posted: Wed Aug 26, 2009 10:57 am
by DestructoMutt
HookLine wrote:Can you link to the experiments confirming this?

Thanks
now posted in "Research and Theory"

thread subject - "Measured product production in VM head"

Re: VM head variations

Posted: Wed Aug 26, 2009 11:53 am
by Husker

Re: VM head variations

Posted: Tue Jul 06, 2010 8:43 pm
by WalkingWolf
LearJet from a completely unrelated thread wrote: I already ordered a 2x2x2 T to replace the 2x2x1 I have now. Looking into some sort of reflux centering device to add when I replace the T as well.
I am currently gathering bits and pieces for a 2" VM build. For the takeoff should I go with the 2X2X2 instead of the 2X2X1. I currently have the 2X2X1 but am not opposed to replacing it if there would be a significant difference in performance.


thanks
WW

Re: VM head variations

Posted: Tue Jul 06, 2010 8:54 pm
by kiwistiller
go 2x2x2. It means that you can get your minimum reflux ratio (and therefore takeoff speed) down close to 1:1 when you want to.

Re: VM head variations

Posted: Tue Jul 06, 2010 9:03 pm
by WalkingWolf
kiwistiller wrote:go 2x2x2. It means that you can get your minimum reflux ratio (and therefore takeoff speed) down close to 1:1 when you want to.

thanks Kiwi,
I have a 1 inch SS ball valve from a previous build. Will reducing down to 1 inch right off the T negate some of the benefit you have noted? Still do not understand the theory behind the minimum reflux ratio (its why I gotta ask all these questions I should know the answeres to by now :oops: )

Re: VM head variations

Posted: Tue Jul 06, 2010 9:08 pm
by kiwistiller
I was curious about that, and it was only made worse by destructomutt (troll of that time) muddying the waters. I did an experiment on my rig. here is the thread.

http://homedistiller.org/forum/viewtopi ... flux+ratio

In summary, reduce away.

Re: VM head variations

Posted: Tue Jul 06, 2010 9:40 pm
by WalkingWolf
Many thanks Kiwi

Re: VM head variations

Posted: Tue Jun 14, 2011 7:57 pm
by blind drunk
I'm thinking of adapting my stainless column and would like to know if a 1/2" gate valve would suffice. I would simply cut into the take off and put the 1/2" gate valve between the column and the liebig. Then extend my column to the correct height and build a modular copper reflux coil head. I found a manufacturer who will sell me the pipe at whatever length I need and will also put the ferule on. They also sell tri-clamps. Two stills in one, I'm thinking. Also, do I need the 1" T to restrict the vapor flow leading up to the reflux coil or can the column be a solid 2", top to bottom. Thanks.

BTW this is what I'd like to adapt -
pothead.jpg

Re: VM head variations

Posted: Sun Jun 26, 2011 3:34 am
by MisterSid
blind drunk wrote:...I would simply cut into the take off and put the 1/2" gate valve between the column and the liebig.
That 's look's to me like the simplest solution...but it will leave you with a very high minimum reflux ratio (about 16:1 by my calculations). Placing a restriction above the take off would solve this though e.g. a restriction plate with a 1" hole in it will drop this to 4:1 which is a bit more usable.
blind drunk wrote:... Also, do I need the 1" T to restrict the vapor flow leading up to the reflux coil or can the column be a solid 2", top to bottom.
Any restriction below the take off will increase the vapour velocity throught the VM, which in turn increases turbulence...which you need to make the VM work. I've got a 1" tee inside on a 2.5" column and still had to insert a scrubber into it to get the turbulence up enough to work predictability. If building again I'd ditch the tee, add a restrestor above the takeoff and use scrubbers to create turbulence.

Hope this helped a little,
Sid.

Re: VM head variations

Posted: Sun Jul 24, 2011 11:22 pm
by blind drunk
Thanks MisterSid, I just noticed your response and appreciate it. I was away for a while and the threads sure move fast around here.

Re: VM head variations

Posted: Mon Sep 26, 2011 12:13 pm
by likkerluvver
Bump
blind drunk wrote:I'm thinking of adapting my stainless column and would like to know if a 1/2" gate valve would suffice. I would simply cut into the take off and put the 1/2" gate valve between the column and the liebig. Then extend my column to the correct height and build a modular copper reflux coil head.....
Did you go anywhere with this BD?
blind drunk wrote:II found a manufacturer who will sell me the pipe at whatever length I need and will also put the ferule on. They also sell tri-clamps.
Now that sounds very interesting. :thumbup:

Re: VM head variations

Posted: Mon Sep 26, 2011 12:25 pm
by blind drunk
You had to drum that up, didn't you :)

I was told that a 1/2" take off would be too small for a VM. I was hoping for a quick fix and aborted the plan when it became more complicated than I wanted it to be. I'll just stick with the one that brung me, my simple pot still, for now.

Re: VM head variations

Posted: Mon Sep 26, 2011 12:41 pm
by likkerluvver
blind drunk wrote:You had to drum that up, didn't you :)
Sorry about that. :oops:
blind drunk wrote: I was told that a 1/2" take off would be too small for a VM. I was hoping for a quick fix and aborted the plan when it became more complicated than I wanted it to be. I'll just stick with the one that brung me, my simple pot still, for now.
Several have used a 1/2" valve, but after reducing from a 1"- 2" column takeoff. These columns do work very well as a simple pot still (with a bunch of copper added for sulphur compound elimination). :thumbup:

Edit from 1' to 1"

Re: VM head variations

Posted: Mon Sep 26, 2011 12:46 pm
by blind drunk
Several have used a 1/2" valve, but after reducing from a 1' - 2" column takeoff.
Right, that's what I meant. I was hoping to just cut a valve in between the column I already have and the condenser that's already there instead of having to do the reductions. I have since bought some copper tubing ... should the need arise.

Re: VM head variations

Posted: Sat Dec 10, 2011 2:52 am
by astronomical
HookLine wrote: I have a 2" column with a 1" take-off port, that reduces to 3/4 through the valve and elbow, then reduces further down to a 1/2" x 3/4" Liebig. It works fine, its maximum output rate is well above what is required.
Did you reduce to 3/4 before or after the valve? Anyone can answer this with their opinion on keeping it 1" or immediately dropping to 3"4 reducer or even using a 1X1X3/4 T

Re: VM head variations

Posted: Mon Dec 12, 2011 3:53 pm
by HookLine
astronomical wrote:
HookLine wrote: I have a 2" column with a 1" take-off port, that reduces to 3/4 through the valve and elbow, then reduces further down to a 1/2" x 3/4" Liebig. It works fine, its maximum output rate is well above what is required.
Did you reduce to 3/4 before or after the valve?
Before. The valve is 3/4".

Re: VM head variations

Posted: Wed Feb 15, 2012 7:11 pm
by Bubba Q
Hey Hook, do you have any pics of your rig?

Re: VM head variations

Posted: Thu Feb 16, 2012 5:27 am
by HookLine
http://s152.photobucket.com/albums/s197 ... ?start=all" onclick="window.open(this.href);return false;" rel="nofollow

Re: VM head variations

Posted: Thu Feb 16, 2012 11:22 pm
by Bubba Q
I meant actual pic of the 2"column with the 1" take off. Did you reduce to via 2x1 reducer then 1x1x1 T or do you T off with a 2x2x1?

Re: VM head variations

Posted: Fri Feb 17, 2012 2:27 am
by Old MacDonald
Hi Bubba,
If HookLine doesn't mind...

His VM 'Head'

Close up of 'Tee'

Drawing of Port

...so it's a 2" S/S column with a 1"/25mm BSP S/S port or take-off.

BTW Hook, some nice coil-work there in your gallery :thumbup:

Re: VM head variations

Posted: Fri Feb 17, 2012 8:23 pm
by HookLine
That's them. Thanks.

Re: VM head variations

Posted: Sat Feb 18, 2012 8:17 pm
by Zombiehunter
Well, I guess there are a few things I just never understood. One is why there is a T in base of the column. Never could see why as if the product is not pure enough it will fall back to the pot anyway without the T. I am not saying I didn't miss something but functionally I don't see it.
I also don't know why everyone seems to lean to the traditional approach of a coil inside to column. I would say a column filled with media (marbles) and cooled externally with a water jacket. Control the temperature at the top of the column by regulating the water into the water jacket and the temperature at the top of the column is fully adjustable. Can also be automated with a solenoid valve and an electronic controller. The vapor at the column top can be condensed by coil or secondary marble condenser running full cooling.
Primary column say 3" schedule 10 stainless about 10-12" surrounded with a 4" schedule 10 stainless jacket a couple inches longer than the inner tube. If anyone is interested contact me.
Contact me if you want to discuss or shoot some holes in this plan.

Re: VM head variations

Posted: Sat Apr 20, 2013 4:32 am
by kaziel
Hi guys :wave:
I'm planing on building VM from 2.5" SS pipe.
4' packed section, ss scrubbers first when i will get some more cash I'm planning on SPP
1' head, takeoff (3/4" thread) , 3/4 full bore ball valve
CSA calculation show that this kind of takeoff will get me 0.09 reflux ratio (kept/refluxed).
Now I'm running boka (1.25") and 750W is my max take-off is 300ml/h ~95%ABV with 1/10 (0.1) RR with my VM setup CSA compare to my LM is 4 times bigger so power input can by 4 times larger right? So can I ran 3kW? Will take of be 4 times faster? Parent size calcs show that I will be collecting 1.4L/h around ~~94%ABV how accurate is that? Should I go for larger take-off?
Anyone? Anything?

Re: VM head variations

Posted: Sat Nov 23, 2013 9:46 pm
by stillermartin
Hello everyone!
I'm also planning to build a VM column and think its a great design! But there is one little thing that my brain doesn't want to understand/accept:

Doesn't the evaporate naturally always want to go upwards? So even with a fully opened valve to the end condeser, istn't there still a good portion going up to reflux condenser?

Re: VM head variations

Posted: Fri Dec 06, 2013 1:55 pm
by Danespirit
stillermartin wrote:Hello everyone!
I'm also planning to build a VM column and think its a great design! But there is one little thing that my brain doesn't want to understand/accept:

Doesn't the evaporate naturally always want to go upwards? So even with a fully opened valve to the end condeser, istn't there still a good portion going up to reflux condenser?
Here is some reading that may put some light on this subject : http://homedistiller.org/forum/viewtopi ... =1&t=11396

Dane

Re: VM head variations

Posted: Fri Dec 06, 2013 5:03 pm
by DAD300
Stillermartin,

If the column and takeoff are the same size the vapor is split equally, if another restriction (valve) doesn't interfere.

http://homedistiller.org/forum/viewtopi ... 17&t=41579

Re: VM head variations

Posted: Fri Feb 13, 2015 2:04 pm
by mepete
I have a 15 gallon boiler, and I plan to build a Boka/VM head. Is there a ratio of column diameter to take off tube diameter that I need to be concerned with. I am very lucky to have a large supply of various size stainless tubing, so my column diameter can easily be 4 inches or larger with plates. Also how much standing liquid should you have in a bubble plate column? Is there a formula for this? I will post photos soon of my completed boiler.

Re: VM head variations

Posted: Fri Feb 13, 2015 9:14 pm
by DAD300
I think you're kidding me but, area of the takeoff vs area of the column makes the ratio. Basically you have the greatest variation of ratios if you keep the takeoff as large as possible.

Look to the link in my signature...

Re: VM head variations

Posted: Mon Feb 16, 2015 2:11 pm
by mepete
I have been considering building a Boka vm design hybrid. I am considering placing my bottom plate of the Boka in such a way that it will help to direct the vapor to the Vm head. This combination seems to be a very good match. I think it would work the best if the top of the Boka bottom plate was about at the same level as the entrance to the VM head. The Boka will only be used for the fore shots and the heads. I saw a similar design of this in a build made by Odim but I have been un able to find it again.
Another question is there a best ratio of column square inch surface area to Vm path take off square inch surface area?
Thanks

Re: VM head variations

Posted: Mon Feb 16, 2015 4:28 pm
by DAD300
The best ratio is always to match the VM takeoff dia to the column dia if possible. It allows the minimal reflux to takeoff ratio of approx 1:1.

If the column diameter is so great that the takeoff must be smaller or only smaller materials are available, I would start thinking CM. As the CM allows for minimal reflux ratio by cutting coolant to the dephlegmator.
PerpenCoilDephleg.jpg
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