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The subject of centering rings has been beaten to death, with some saying "they work" and others saying "they aren't needed." Many new distillers start with a 2" reflux column using VM, CM, or LM. Usually packed with scrubbies or similar. And that's where I'm at right now.

I'm well along on a VM mix-valve hybrid (http://homedistiller.org/forum/viewtopi ... 15&t=48599) that is going to have an odd and irregular reflux flow past the VM slide valve area. Because a lot of the reflux liquid is going to be routed to the edge of the 2" column, I've decided to add some sort of centering ring.

Being 20 pages into "Flute talk" I thought "Why not add a flute-style perforated plate above the column packing, and below the VM take-off?" In other words, instead of a copper ring with maybe a 1.25" hole in the middle, create a no-kidding miniature perforated plate about 2" above the top of the packed column. Nothing fancy, just a boat-load of smaller holes rather than one big hole in the middle. Vapors up penetrate the holes and "boil" a shallow layer of reflux condensate.

There could be one 3/4" copper j-tube dead center that is maybe 1/4" above the level of the plate; if distillate builds up, it'll flow down the pipe and exit close to the middle. The J-bend prevents vapors from climbing the 3/4" pipe, forces them through the perf holes.

Would this be pointless? Worst case, you'd have a nice even rain of distillate onto the packing, definitely mixing with upcoming vapors. Best case, improved ABW and potentially a "touch of the flute" in terms of flavor, although being at the top of a packed column, it'll all probably be 90+% ABW in that region anyhow.

Probably would do just what you said. Might want to make it removable.

heartcut wrote:Probably would do just what you said. Might want to make it removable.

The way I'm seeing it, if I'm going to do a ring, making it in this style can't hurt, might help. And it'll be in a "gasket" format between two tri-clamp ferrules, so yes it'll be swappable and removable.

Thoughts/opinions appreciated, thanks.

Edit: spelling

Plates are best used under the column, not on top. Why? Super scientific reasoning I cannot recall. I read a bad ass thread on this very subject about using plates and packing at the same time. Let's see if I can find it again, as it would be good for me to re-read it.

After watching videos of Odin's glass still, I gave up on the whole centering ring concept.

Before you start drilling a thousand holes...these are available commercially, SS, I wish I knew the void area specs...quit cheap $3usd for a 2". They fit in between triclamps. Using anything that reduces the area of the column, speeds vapor. The idea of centering reflux through a small hole of speeding vapor has always seemed counter productive. You purposely create a choke point.

Without a centering ring, the scenario people fear, is the reflux channels down the column wall, where when it reaches the higher temp it vaporizes, expands and starts back up. Remember a lot of early reflux columns had the reflux return on the outside of the column!

I see no benefit to centering reflux. Especially if the side effect is speeding ascending vapor.

Glass columns have proven that a properly packed column does not allow channeling down the column wall. If the packing is tight enough, it pushes the reflux to the center.

On the other hand, I'll be waiting for your data.

DAD300 wrote:Remember a lot of early reflux columns had the reflux return on the outside of the column!

Not just early designs. I have experienced positive results from adding an external reflux circuit to my dual slate plate boka. If I built another LM, it would definitely be inline with an external reflux circuit similar to what is seen throughout Hookline's "some still drawings" pdf. Minus the vapor lock after the takeoff valve. Packing the liebig with a scrubby is a far simpler solution.

Very nice find btw. You have saved people here some serious cash with posts like that.

I don't think there necessary either, even using lava which doesn't pack against the wall like scrubbers ect do, it still works we'll without centering. A 3/4" j would be hard to fit in a 2" column in the center let alone on the side like normal plates,, unless you had a very tight radius on the bend!. I put a single bubble plate in the top of a 4" lm and it was a bit of pita to keep loaded.

Good stuff. The way my " mix valve" design works right now, a hefty 2" stainless pipe will run cross-wise to the column, and the reflux is going to hit that and roll to the edges. If typical scrubbie packing wicks it evenly away from the walls, then no ring is necessary or desirable.

Agree with the notion that a plate above packing won't behave like a plate in a true flute system.

We'll see how it goes. A ring or plate that simply goes into a tri-clamp joint is something that would be a fine experiment. It can go in and out in moments with no permanent mods, so it'd be worth trying. Worst case, no effect, or maybe choking/flooding. Best case, improved ABW.

That's one reason I like a modular design, you can try different and interesting things.

BigSwede wrote:That's one reason I like a modular design, you can try different and interesting things.

If it doesn't work great on the top, put it on the bottom where it will work for sure.

I now have one of those perf plates at the bottom to hold my SPP in. No ill effect noted.

DAD300 wrote:I now have one of those perf plates at the bottom to hold my SPP in. No ill effect noted.

Dad300, I really like your experiments with SPP, and your outstanding contributions to the craft in general.

I've got a box of maybe 8 pounds of #14 bare copper wire salvaged from a house build. They're all 10" to 24" long. Every time I walk by them, they whisper "Turn us into copper SPP. Do it. You know you want to."

Totally changing the topic here, but do you think copper SPP is workable or even desirable?

This valve design is about 30% complete, coming along nicely. I've taken some pics, I'll get them up as a build. This will be the last fabrication I'll do with the exception of the plumbing and final assembly, then it'll finally be time to ferment. Total time from "I want to do this" to actually running a still - 4 months.

BigSwede wrote: Totally changing the topic here, but do you think copper SPP is workable or even desirable?

It should work fine. It is said that if using a large quantity, then the bottom spp will be crushed under the weight. It also corrodes unlike SS would, and thus might not last ten thousand years.

If you don't have an exceptionally tall column, I say go for it.

#14 is .064" dia...a bit large. It would work as a packing, but the HETP is a ?

My largest wire is .031" and is great in a 3" colum.

There is a point where copper wire will crush under it's own weight, but #14 would take a lot. It wouldn't take long for you to make a quart or two of it and find out.

I would think putting a plate at the top could only lead to flooding. I reduced the size of my lava rock now so that it takes less heat input to maintain a semi flooded state within the column. You can hear it boiling inside. If I adjust my heat input up a bit I bring the flood right to the top of my packing and can hold it there. I put a sight glass in so I could observe this along with one across from my bottom plate to observe reflux.

It did not seem to make sense to me that holding the aquatic state at the top of my packing was really beneficial so I have just done it a few times for observation and backed the heat off so I could hear it move down the column more.

DAD300 wrote:#14 is .064" dia...a bit large. It would work as a packing, but the HETP is a ?

My largest wire is .031" and is great in a 3" colum.

There is a point where copper wire will crush under it's own weight, but #14 would take a lot. It wouldn't take long for you to make a quart or two of it and find out.

hi dad 300
what size and dimensions are ur spp packing,
looking to have a go make some myself,
cheers

Hound Dog wrote:I would think putting a plate at the top could only lead to flooding.

Agree, which is why if I try it, I'll create a path that will allow excess pooling to strongly drain if it builds up too high. But yeah, a plate above packing in a reflux column won't be doing much. If in a stable 100% reflux mode, everything that makes it up there will be close to azeo anyhow.

Although in a pot still mode... maybe some benefits. Hmm...

Ment to add this on my first post Swede, just some more info I hope helps. http://homedistiller.org/forum/viewtopi ... 17&t=42591