A 3 inch three plate and 4 inch three plate

[Jack C]

Since joining the forum I thought I would post the last two columns that I put together.

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The 4 inch has the standard 5 up and one down bubble caps per plate.

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The three inch I made some single caps pattered off of the pro cap style bubble caps.
Both seem to work well.
I have a 4X4X3 tee with a plate I can install under either one if I want 4 plates in a run. They both run 75% to 80% pretty well and that gives me enough flavor carry over for most things that I make.

[Saltbush Bill]

Nice work Jack

[Jack C]

Thanks Saltbush. The one big mistake I made is making the sight glass stubs to long on the 4 inch. That extra 1/2 makes it hard to see inside and installing the caps requires you to call on the patience of the gods.

[Saltbush Bill]

Yep always best to keep the glass in as close as possible to the main column, the view is much better.

[acfixer69]

Yep closer to the column and lower to the plate. Back pitched is a plus too.

[Jack C]

Yep. I learned the back pitch once the hard way. It was when I put them all backpitched the wrong direction. I remembered that and forgot about getting as tight as possible. Thanks acfixer

[Jack C]

A couple pics of the single caps.

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[Corsaire]

Very neat design on the single caps. Thanks for sharing!

[Tabucowboy]

That looks awesome!

DO you have a drawing to better show how you made the bubble plates?

[Jack C]

I am sorry I do not but will try to do one and post it.

[Jack C]

With the added 4th plate.

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[LWTCS]

How are you preventing return liquid from going down your downcomer?

[Jack C]

I soldered the 3/4 cap to the side of the 1/2 downcomer and it is tilted slightly. The liquid coming down drops just outside and against the out edge of the cap. The 1/2 downcomer tube is also slightly angled. It was a close thing, when doing my cleaning runs I was watching that close and was ready to solder a small tongue onto the bottom cap if needed.

[Jack C]

A very rough sketch of single bubble cap.

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[Jack C]

How are you preventing return liquid from going down your downcomer?

LWTCS after running two 13 gallon boiler loads and watching the down comer. It drops fluid into the one below about 10%-15% of the time. I can only attribute it to changing pressure and turbulence in the column. Instead of putting something on the bottom of the plate I think I will put something on top. I am thinking like a umbrella over the hole. Maybe 1 inch above it on three little legs. Should be out of the way and not bother the operation and stop that waste of energy by stopping the alcohol from bypassing a plate. Will post pic when built. Also I think I will build another set of plates for the 3 inch with larger caps. Seems a wasted some room on the others.

[NineInchNails]

A very rough sketch of single bubble cap.
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VERY cool design!
I was thinking of scaling this down to make plates with three 3/4" caps (in a 3" column) which would give a total circumference of 8.98" of cap. A single 2" cap would give 8.94" of circumference. I don't think that's enough of a difference to notice and MUCH less expensive too.

[Jack C]

When I get home I will be making a set of 2 inch for the 3 inch column. To be totally honest I just copied SD’s procap. The only thing I will do different when using a single cap is put a copper umbrella over the center hole.

[NineInchNails]

I'll be doing one of these for a 3" very soon, but two plates in one sight glass. I intend to install a plate below the glass and one above the glass.

Instead of a copper umbrella, what do you think about soldering a few elbows to create a U trap and just direct the flow to the side? That would cost a bit more in fittings, but that should work.

[Jack C]

That would work fine. You just don’t want the downcomer fluid to skip a plate. Wastes a lot of energy when it does.

[Yummyrum]

This was to spread reflux into packing in my stripper but you could adapt It to your single cap centre downcomer plate.

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[Jack C]

Very nice yummy. I am going to make some 2 inch single cap center drain plates for the three inch. I am going to try the umbrella over the hole in hopes it gives me additional surface to flash alcohol.

[Jack C]

Well I started my 2 inch caps for the 3 inch column.

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I also made three additional covers that I am going to make umbrellas out of to cover the center hole. I hope that the umbrella cover will also help flash alcohol that is dripping from the plate above and stop the plate bypass of falling down the center hole.
Will post more tomorrow as they get built.

[LWTCS]

Try and make sure the open area on the drains is larger than the open area on the vapor path.

[Jack C]

I was going to use a 3/4 down tube and maybe a 1 inch cap at the bottom for a vapor lock. I will sit down and do the math to see if I am close. It will have a 1.5 inch hole thru the plate for vapor rise under the cap that extends above the plate just above the vent slots in the cap skirts. I have noticed that the 1/2 inch down tubes in the other ones I made are way to small. The 5.5K element will run over them pretty easy if you push past 75% heat input.

[LWTCS]

Doesn't have to be.
But so much more compliant behavior if the drains are not the bottle neck.

[Jack C]

Well I got a little more done with the caps. I still need to make the vapor block on the bottom of the down comer.

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I did do the math and the vapor path up has a little more volume than the liquid path down. Once I get the vapor lock on the bottom we will see how it works. Not sure what to call this style bubble cap. It either junk and a waste of time or some type of castle top cap. Ha. Hope it works.

[NineInchNails]

In jack C's original design the area of the opening for the vapor path should be approx 0.68 sq". The area of the opening for the down-comer should be 0.31 sq". It appears in this case that the area of the drain is significantly smaller than the vapor path.

If we use 1" pipe and 3/4" pipe then the area of the area of the vapor path should be approx 0.39 sq". The area of the opening for the down-comer should be 0.6".

So it appears that 1" & 3/4" pipe is more appropriate. Keep in mind that my calculations are going by the OD of the pipes. I'm not accounting for wall thickness, ID and I don't think it will make much if any difference.

Thanks LWTCS and Jack C! I never considered that technical detail and if you didn't mention it, I think I would have made mine as per the original design.

Jack C, if it is possible, you might consider making an edit in your original post noting this so people don't make an error in the future.

[LWTCS]

Notwithstanding big oil's patent on a very similar concept in like 1937 or some such,,,the 2nd and 3rd generation originals.
The big oil design has a ring of dental work around the perimeter of the top of the cap to promote laminar flow. Thought we had an original thought with this. In retrospect pretty arrogant thinking hahaha.

Gen 3 is definitely built for speed.

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[Jack C]

Nice LWTCS. Also the pipe for the vapor up is a coupling for 1 inch pipe so it has a diameter of 1.125, not 1 inch.

[Jack C]

Well finished them up. Need to do vinegar run and the runs some feints thru them to have them ready for a wash.

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