2" Bokakob condenser theory....

[vetting]

Was having a thought today about how to get faster output out of a boka column. Even though the slant plates overlap, I would assume that the some of the distiliate that condenses on a double coil dont wind up where its supposed to go. Also, it might be more effiecent to drop a large portion of directly on the lower plate from there, the overflow can get directed right down the center of the column via the drip tab. So what about adding a drip director of some sort to the bottom of the coil to point right towards the bottom plate. Would be even easier to build something that sits below a cold finger and coil.

I can rig some different coils up and do some testing to see what the best style of condenser is. Any thoughts? Anything you would like for me to try?

To test, run just water.
Get up to full temp and set MK controler at a set amperage.
Try the first condenser with the waterflow at a certain rate.
Time how long it takes to collect 200ml
Switch to 2nd condenser and repeat
Go through all of the condensers and then swtich back to the first one to see if the 1st test gives the same results.

[Usge]

Vetting...I hear ya. I used a 3/4" copper "stubout" for my cold finger. Its shaped like a tapered cigar end on the bottom. But, as you suggested...because the way the boka works...all you need to do is make sure the refluxed distillate is getting to and filling the plates. The overflow from plate tab will direct it to center. Some people have added centering rings. But, tend to suggest that these would be more useful in the bottom half of the column where the mingled distillate/relfux/vapor might contain more heavier water and be more prone to channel it's way towards the column walls (as opposed to the very top).

[rad14701]

The condenser doesn't control take off rate, nor does slant plate configuration for the most part... I guess I'm not following your logic on this one...

The original Bokakob mini-still had the top plate soldered directly onto the bottom of the reflux condenser... That has changed as the design has been improved over the years...

The design has also been run effectively with single helix, double helix, triple helix, cold finger, and probably even a few other types of reflux condensers... They have even been constructed to use an alternate reflux return line rather than relying on the bent tab as the primary reflux location...

What, exactly, are you looking to prove that hasn't already been attempted...??? The design has been modified extensively but none of the modifications have really improved performance beyond what the most simple implementation provides...

[Odin]

Vetting,

Only 25 posts and already deep in the theory on LM design! Congrats! I think, Rad, I understand what Vetting is aiming at. If you could collect everything your "cold finger" throws down, instead of just a part ... your collection rate would go up, right? Problem being, that you do not want to collect everything. Refluxing down the column instead of collecting is what attributes to more purity. The aim is not in collecting as much as possible, but in collecting "just as much" to allow refluxing to obtain maximum purity at around 95/96%.

But tell me if I see your thought experiment wrong!

Odin.

[rad14701]

You can't knock down and collect more than 100% of the rising distillate vapor... And a portion of that has to be returned as reflux into the packed column as that is how reflux columns work... You can only collect as much as possible while returning enough reflux to maintain equilibrium within the packed column...

[Usge]

I think what he was referring to...was trying to "aim" or direct the refluxed distilalte off the coil to the bottom plate somehow more effectively.

[vetting]

Well the output measurement with the water test is to measure the effectiveness of the different condensor in regard to putting the distilate right on the angled up plate. If that output is greater, then you could technically have a higher output rate when running in reflux because you could still run the same ratio. The whole reason I started thinking of the idea was because my stripping runs take longer than I would like. Granted it takes awhile to strip 14 gallons with an output of 3 gallons, but just wanted to see if I can speed up that part of the process.

[vetting]

Vetting,

Only 25 posts and already deep in the theory on LM design! Congrats! I think, Rad, I understand what Vetting is aiming at. If you could collect everything your "cold finger" throws down, instead of just a part ... your collection rate would go up, right? Problem being, that you do not want to collect everything. Refluxing down the column instead of collecting is what attributes to more purity. The aim is not in collecting as much as possible, but in collecting "just as much" to allow refluxing to obtain maximum purity at around 95/96%.

But tell me if I see your thought experiment wrong!

Odin.

Odin - you hit it right on the head. Aiming at collecting more on the plate and more efficiently and keeping the same overall reflux ratio. Since there is no accurate way to measure this, the water experiment with collecting everything will be used to determine what kind of condenser is best and if modifications to traditional designs makes an improvement.

[Prairiepiss]

Ok I'm not understanding it either? If you have a condenser that will knock down 100% of the vapors and 2 plates that overlap under it. The lower collection plate should have 100% of the reflux hitting it at all times. How are you going to collect more then 100%? At this point you are only slowed down by the amount of vapor you are throwing at it? So the way I see it the only way you would be able to collect faster is give it more power input. Unless your takeoff valve is to small to take off 100%? If that's true none of this really matters till its replaced?

100% is 100% you can't get more then that?

[Bagasso]

Your assuming that the condensate is not dripping into the bottom plate. If constructed correctly I don't see why it wouldn't. Even if you got the odd drop evading the bottom plate it is still just goint to be refluxed.

[vetting]

Just toss'n the idea out there. Im willing to waste some copper to try out an idea and if it doesnt work it doesnt work.

[rad14701]

Just toss'n the idea out there. Im willing to waste some copper to try out an idea and if it doesnt work it doesnt work.

Why not try explaining the theory first... I think we've already explained why what we believe your theory to be is invalid... All vapor gets condensed and either drops onto the upper or lower plate and it all ends up on the lower plate... From there you either collect it as spirits or it refluxes to be reboiled in the structured packing... The needle valve allows you to vary the amount of reflux from 100% down to zero percent... In order to maintain a vapor gradient within the column, which is the crux of reflux columns, you need a minimum amount of reflux to make that happen... Is there part of that theory that you think is flawed and have a better idea...??? If so, please share... We'd hate to see you wasting time trying to reinvent the wheel - or the liquid management reflux column...

[vetting]

Just toss'n the idea out there. Im willing to waste some copper to try out an idea and if it doesnt work it doesnt work.

Why not try explaining the theory first... I think we've already explained why what we believe your theory to be is invalid... All vapor gets condensed and either drops onto the upper or lower plate and it all ends up on the lower plate... From there you either collect it as spirits or it refluxes to be reboiled in the structured packing... The needle valve allows you to vary the amount of reflux from 100% down to zero percent... In order to maintain a vapor gradient within the column, which is the crux of reflux columns, you need a minimum amount of reflux to make that happen... Is there part of that theory that you think is flawed and have a better idea...??? If so, please share... We'd hate to see you wasting time trying to reinvent the wheel - or the liquid management reflux column...

My theory is that not everything is making it onto the lower plate and not in the most efficient manner. Some probably is even revaporized as the steam is rising past it rather than proper refluxing back in the packing. Or it could have the opposite effect of having the vapor not even making it to the condenser. As the distillate drops from the upper plate to the lower, steam is going right past it. So why not just give it a shot with directing a majority of the condensation directly towards the lower plate to see if it makes a difference.

The only real way to determine how the distillate is flowing is if you could mount the plates inside of a glass tube at the top of your boka. Other than that, they only way I can see is to just give my theory a shot and I'll mock up 3 different condensers. I love working with copper and don’t mind some messing around. I make parrots in my spare time and sell them on the board here - so trust me, its not a waste of time to since I like working with copper and like to experiment. Worse comes to worse, it doesn’t work - I have some condensers that I can sell on the board.

[rad14701]

vetting, I think you're over-thinking things here... Hold off on any experimental builds at least until one of other members finishes his build of a Bokakob dual slant plate complete with a sight glass right at the slant plates... It will give a clear view of the condensed distillate coming off the top plate as well as the collection cup formed by the lower plate and the reflux dripping back down into the packed column... Remember, reboiling is what creates purity so any reboiling at the plates is a desirable trait and not a nuisance... See this post for the image Kiwi-lembic posted today...

[Kiwi-lembic]

cheers Rad .hope alls good ,playing with the view of those plates right now ,im staring straight at the bottom plate and a clean shot of the top plate thru my glass ,will be interesting

[shenandoah]

kiwi-lembic,

What parts were used to build the sight glass bok? I'd really like to build one of those.....Thanks.

Shenandoah