Brian's 8 Plate Bubbler

[YHB]

Don't get too excited, this is only the start of the thread the end is many months away.

My current overseas posting has taken me away from my shed and all related activities for over a year. However I now find that SWMBO has been maintaining my budget of 5 pounds a week so I now have a little slush fund that I can dig into for related bits and pieces.

So I am now starting to gather bits for my bubbler. 2.1/2" copper column with modular plates every 125mm, each with one 35mm Bubble cap, and no sight glasses, not unlike the Baby Dragon. Except its not glass. Fester (AKA Lloyd) said that he had no objection to anyone copying his design for their own use, but drew the line at commercial enterprises, so I am taking him at his word.

I was back in the UK last week and ordered all the Copper bits that I did not have;

1.5m x 67mm (2.5") Dia Pipe
2 x (67 X 54) Reducers
8 x 35mm Caps
8 x 22mm Caps
8 x 22mm Slip Joints
About 60 pounds for the lot

All except the reducers arrived in a couple of days.

I am now back at work and I brought enough bits to make one sample plate. I have this stupid fantasy that I can fabricate it in a hotel bedroom. I know that when fantasies become realities they are often disappointing, but I must do something, I am starting to come down with cabin fever.

So here goes for a very slow ride.

[Anavrin]

Hi Brain

I'll be watching this with interest.

I was wondering if something similar could be made with those tri-clamp sight glasses, maybe trap a bubble plate between two sight glasses in the middle of the tri-clamp if you get what I mean, would be very expensive tough, I could possibly buy one sight glass per month :-(

[YHB]

Hi Brain

........gh, I could possibly buy one sight glass per month :-(

Make one per month......you get them in the same period but save a lot of money.

[Anavrin]

If you attach a 2 1/2 - 3 inch column to a boiler that has a 2 inch hole with a tri-clamp reducer, would you be reducing the output to that of a 2 inch column because of a restriction on its input or does this not matter?

I don't think it would but have no knowledge of the theory so thought I'd ask?

[YHB]

It just makes the vapour go quicker / slower dependent on the size of the hole.

The bubblers deliberately have small holes to make the vapour travel quickly and make small fizzy bubbles. it also helps to have more heat / vapour for the same reasons.

With a reflux still its not the same, where a smoother / consistent /slower flow is more desirable, having said that it appears one reducer top and bottom does not seem to cause any problems.

[ant]

The very short length of the restriction at the boiler connection means it will have no real effect to worry about. The vapour will speed up briefly and quickly slow down again as it passes the restriction. It is common practice.

It has even less effect at the top. Capt can drive his column harder when he uses his bubble ball below it. The more concentrated vapours are not as restricted for throughput as the less concentrated vapours for a given column dia. There is less work to do as you go up the column and more and more water has already been removed. I have seen you tube videos of glass columns packed with SPP that had a fat column at the base with a thinner column on top. The fat column allowed the thinner column to be driven harder than if the thinner column extended all the way down.

Personally I think a bubbler is a better way to achieve that than a fat packed column. Less hight and mass for the same effect. That is why I made a bubble ball to begin with.

[YHB]

Just getting things sorted in my head.

Overall I want it to end up with 8 sections something like this.



Take out the bubble cap and leave them untill later



I am not very good at mass production - after I have made the first one of anything I get very slipshod with the rest, but I am going to make an effort on this. So this weekend is about making formers to try and get the bits similar.

Its a long weekend here, so it will give me something to do.

[ant]

Looking at the lower picture is that sorta two pieces? An upper piece which is a pipe with two flanges and a lower piece that fits inside the upper piece to support the bubble cap and provide a slip joint into the next module below? I will be very interested to see how you form these.

[Anavrin]

I can see the vapour path through the bubble cap but how does it work for the liquid returning without a seperate downcomer?

I've cheated and bought a Still Dragon torpedo section, it has 5 bubble caps and 1 downcomer and will fit between my boiler and column with tri-clamps, once I get it I'll post pics of the bubble cap components, maybe they can be copied with home made copper bits.

[ant]

The central pipe goes up through the bubble cap and has a cup underneath it so I assume that is the downcomer. I am more hazy on how the vapour gets up under the cap.

[YHB]

Sorry folks, back at the hotel and limited to an android tablet, when I get back to the office in a few days I will draw a picture of the vapour / distillate paths.

The clue is the hole in the side of the outside tube is a two way street.

[ant]

Well yes, I can see that is where the liquid exits and the vapour comes in. It must go up the annular ring between tubes but is the top of the outer tube just open with the edge of the bubblecap ultimately supporting the downcomer or is there some mechanical connection between the two tubes? And why does this design not need a sightglass again?

[YHB]

And why does this design not need a sightglass again?

Does not need? May not need? I think it will not need?

This is still to be proven but I cannot see it being an issue.

From what I can see there are four reasons why people use SGs.

1/ they look cool
2/ to see if a sieve plate has collapsed
3/ to check when tails are coming throught by watching for the SG to mist up..
4/ to see if the plate is flooding

Only number 4 is relevent to me, with this type of bubble cap you have one downcomer per riser whereas the traditional plates and bubble balls have 4,5 or 6 risers per 1 downcomer.

Looking at the videos one of these caps can take 3 kW without flooding.

So if it cant flood what is there to look at?

Or am I missing something???

[Anavrin]

Found a youtube video showing a 4 plate colunm with single caps in each plate, looks good, output is 2.5 litres per hour with a 2.5inch column and 2.4KW power.[url][/url]

You cant see exactly how the bubble caps allow the liquid to pass back down the column but sure enough its happening :-)

https://www.youtube.com/watch?v=kOA6L3eVTBg

[YHB]

That's the one I am basing mine on, I have always had something like this in the back of my mind. This one promted me to actually make a start.

From reading othere posts of his,I think Lloyd's figures here are over generous, time will tell.

Any more than one cap per plate and I would be running out of power and making too much booze. (Did I really just write - too much booze??