4 inch Liebig Condenser on a 2 inch Boka

[APR]

I've noticed that the spirits discharge from a boka I have is at a fairly high temperature, and you can see a very small amount of vapour around the top of the collection container from time to time. So, for the exercise I ran water through the boiler and a short Boka to measure the temperature of the condensed water going into the collection container.

With the water boiling away merrily and the temp gauge in th eBoka head measuring 100 deg C, the water leaving the discharge [youtube][/youtube]spout was around 80 degree C.

I put together another Boka head and incorporated a 4 inch Liebig condenser into the discharge spout so I could see what cooling effect a 4" Liebig would have on the temperature of the liquid leaving the spout.

The 4 inch Liebig on the liquid discharge cooled the liquid down 25 degree C.

While I did the exercise using water, I expect a similar reduction in the liquid temperature when distilling alcohol.

My young bloke is of the opinion that there is no need to cool the discharge liquid down, and that what is evaporating off are the more volatiles, however, as we typically do a stripping run and then do a final distillation for neutrals I don't believe we need to be too concerned about maintaining the discharge liquid temp to promote evaporation of the more volatile components. What do you blokes think?

Here are the two Boka heads I used....





The Liebig is 1/2" over 3/8" but I have ground a couple of flats down the side of the 3/8 to give more clearance for water to flow through.

[Yummyrum]

Good stuff. APR
Did it cool it by 25 deg or to 25deg ?

While your here you better elaborate in the home made needle valve.That thing looks cool.

[badbird]

the discharge was around 80 degree C

At 80C you are loosing ethanol as well as the other stuff, apart from that its a fire hazard.
The little liebig maybe with a bit of scrubbie stuffed up it is just the thing.

[APR]

Good stuff. APR
Did it cool it by 25 deg or to 25deg ?

While your here you better elaborate in the home made needle valve.That thing looks cool.

Cooled it down by 25 deg C.

I have made up a couple of different needle valves, but they are pretty much identical in how they work internally. I have fabricated a valve using bits of copper tube as seen on the Boka head that is fitted with the 4" link Liebig, but it is a pain with soft solder joints melting and the whole thing falling apart as you try to assemble it. I ended up using high temp silver brazing rod to assemble the bits of tube, and then used soft solder to attach it to the 2 inch and attach the discharge spout.

I much prefer the design using a block of copper as I can drill it out and the soldering is minimal. I have modified the design from my original but haven't updated the drawing as yet.....



I have modified the valve by not threading the body but soldering a tube to the top of the block that has the thread in the tube...



My eyesight is not as good as I would like, my solder preparation is sometimes pretty mundane, and my soldering can be shite as a result.

A few points about making the valve block... A drill press and drill vice are just about a necessity. Copper tends to expand onto the drill bit and grab.

To put the point on the SS Alan head screw I hold the screw head in the drill press chuck, rotate it on low, and hold the side of a rotating cutting disk in a small angle grinder against the end of the screw to shape the point. It is worth spending a bit of time stuffing around to get the screw to run true before grinding so the end of the screw ends up on centre. After grinding I polish the point with fine paper.

I bought 12mm x 30mm x 250mm copper bar from this seller....I note he doesn't have the same size bar listed now...

http://www.quicksales.com.au/ad/copper- ... am/1837426

I bought 1/2" round from the same bloke, and I used some of that to make one tap, but I mainly bought the 1/2" round to make a couple of thermometer mounting tubes.

[APR]

the discharge was around 80 degree C

At 80C you are loosing ethanol as well as the other stuff, apart from that its a fire hazard.
The little liebig maybe with a bit of scrubbie stuffed up it is just the thing.

The 80 degree liquid discharge temp was using only water (no alcohol) in the boiler while testing the concept of the small Liebig to see what sort of temp reduction I would get. I have a 2" boka with 900mm of reflux packing that I am thinking of now adding a small Liebig to.

EDIT: In the drawing of the valve in the post above, the 3mm hole for the end of the screw has been increased to 3/16".

[Yummyrum]

Thanks mate.You've got some good things going on there.

Does the needle valve have good control.I only have a ball valve on mine and it sucks.

BTW the 4" Liebig.......what sort of flow do you have through it...just roughly.Like what sort of pump feeds the Reflux coil its in parallel with ?

Do you think its flow is maxed out ATM or could you push it harder ?

[APR]

Thanks mate.You've got some good things going on there.

Does the needle valve have good control.I only have a ball valve on mine and it sucks.

The valves are really good for control. What I have stuffed up when playing around is the amount of fall from the 2" boka through the various bits to the end of the discharge spout. I put a valve and spout together where the spout at the valve came out horizontally with no initial fall. Fluid built up at the start of the spout until you suddenly had a very short duration gush at the end of the spout with nothing for a while and then another short duration gush. You can see with the block that after making it I angle the back where it attaches to the Boka (or the tube that goes to the Boka) so everything has fall and individual drops don't hold up on flat sections and then surge through.

BTW the 4" Liebig.......what sort of flow do you have through it...just roughly.Like what sort of pump feeds the Reflux coil its in parallel with ?

I bought a Still Spirits water control tap and that fits onto the kitchen tap. When I cut the 3/16 tube going to the Liebig I used a cheap tube cutter that you rotate around the tube. The cutter tends to nearly close off this small tube. I opened up all of the 3/16 tube ends except one which I left as a restriction to limit the amount of water going to the Liebig. The condensor has an outer coil, an inner coil, and a cold finger, with all water coming in the top and out the bottom of the condenser so it is pretty efficient. When adjusting the water feed rate I adjust it to give a discharge water temp from the condenser of around 55 degree C. The Liebig is getting bugger all water but then it really only has to cool the small amount of fluid coming out the discharge spout down a bit.

Do you think its flow is maxed out ATM or could you push it harder ?

While there is not much water going through the Liebig, the return pipe is barely warm to the touch. I wouldn't say it is an efficient Liebig, but I will be happy if it does reduce the ethanol temp going to the collection container by around 20 - 25 degree C. Now I just have to modify my main Boka and see how it goes. We will probably pension off our original pot still (it is a roughie but it got us started and my young bloke thinks it is great) and use one of the Boka heads with no reflux for our future pot distilling.

[APR]

BTW the 4" Liebig.......what sort of flow do you have through it...just roughly.

All the condensers I have so far made are inner coil, outer coil, and a centre finger with inlet at the tiop and all water flowing to the bottom of the condenser where it exits. hen distilling we normally have the water discharge set to a max of 55 degree C and use less than a litre a minute. I checked the water usage today when only running water through the Boka head and we were still less than a litre a minute water usage to maintain discharge water temp under 55 degree C. This will change if the amount of power going to the boiler changes. I am just about to install a voltage gauge in our power controller so I have a better idea of the wattage going through the boiler.