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aga
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It's more fun to just type a reply with no quote.
The delay allows others to reply before you do, thus causing all sorts of mayhem.
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Magpie
lab constructor
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For multiple quotes I open a 2nd window. Then just block and copy to the first window. You have to remember to enclose each quote with the proper BB
codes. This may be crude, but it's effective.
[Edited on 11-3-2015 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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Fulmen
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Quote: Originally posted by Zombie  | | Even when I try to use the "quick reply", and go back one page to pull a quote, my response disappears. |
Yes, that will happen. Other software allows you to see the thread below when composing, sadly this doesn't. The trick is to pull up the thread in a
new tab.
Some browsers have shortcuts for this, don't know what they are except on Firefox. But there you simply press [AltGr] while clicking a link or the
back-button.
We're not banging rocks together here. We know how to put a man back together.
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Zombie
Forum Hillbilly
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| Quote: Originally posted by Magpie | For multiple quotes I open a 2nd window. Then just block and copy to the first window. You have to remember to enclose each quote with the proper BB
codes. This may be crude, but it's effective.
[Edited on 11-3-2015 by Magpie] |
Maybe...
| Quote: Originally posted by Fulmen | | Quote: Originally posted by Zombie | | Even when I try to use the "quick reply", and go back one page to pull a quote, my response disappears. |
Yes, that will happen. Other software allows you to see the thread below when composing, sadly this doesn't. The trick is to pull up the thread in a
new tab.
Some browsers have shortcuts for this, don't know what they are except on Firefox. But there you simply press [AltGr] while clicking a link or the
back-button. |
Maybe more...
| Quote: Originally posted by aga | It's more fun to just type a reply with no quote.
The delay allows others to reply before you do, thus causing all sorts of mayhem. |
By George I think he's got it.
That second tab was the trick.
Thank you guys. I owe ya' one! 
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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aga
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Oh good.
When can we expect repayment ?
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Zombie
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What do you need my friend?
I'll not share my sample red head but all else is open for discussion.
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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aga
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Perhaps a little Science ?
It is called Science Madness after all.
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Zombie
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Hmmmm.
Now to wrap my head around that one. Constant challenges here.
Sure you don't want a puppy or something? 
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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aga
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Nope.
Some Science would be good.
Chat shows we already have.
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aga
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... and as for Science, an Experiment has happened.
The initial results are a bit confusing, but then, this was a test of the apparatus, sensors etc.
First off, is the 'Thumper' so-called because it causes the first distillate (from the boiling pot) bash up and down in the thumper feeder pipe ?
Second, is fairly violent suck-back from the Thumper to the boiling pot normal ?
If so, that would explain why some people say that an empty Thumper pot is best, although suck-back would probably occur after it fills up.
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Crowfjord
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Hooray for experiment! I will begin my own attempts this Friday and/or Saturday.
I would expect suck-back at the end, when the pot cools down. Was this the case?
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aga
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What i saw was the distillate from the boiling pot crashing up and down in the feeder pipe to the Thumper pot, suggesting (to me) the reason for the
name.
Semi-violent suck-back occurred after about 15 mins, dumping almost all of the Thumper load back into the boiling pot.
It may be bad design, so don't take anything as 'fact' just yet - this was just a preliminary experiment to try to establish some parameters, now that
the required glassware has arrived.
[Edited on 18-3-2015 by aga]
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Loptr
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So the thumper does provide reflux by returning the distillate to the pot?
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aga
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No idea yet.
Suck-back occurred in the experiment is all.
Might just be an error in the design.
It would be nice if Zombie would describe the functioning of a Thumper in more detail, so the experiment can be more accurately designed.
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Zombie
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There should be no suckback. Perhaps it will occur on cooling but not when running.
I am guessing the "thumper" pot was too high in relation to the boiler, or there is an air/vapor leak on the boiler fitting.
The other "maybe is you were heating too hard.
The object is to simmer That is the most efficient way to extract drinking EtOH, and that is what you are trying to replicate.
The term "thumper" is because of the noise. The thump intake will make a pounding sound that slows down as the thump heats up
I would try to make the bottom of both containers as level as can be.
I would also try to control the heat to keep it to a minimum. Just above simmering, and try to keep it there for the entire run.
If you have a thermometer in there the vapor temp should be above 170*f, and below 212*f
That will rise as the EtOH boils out but it is a fair guide.
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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aga
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Thanks for the info.
Just a guess : the word Thumper must mean that it makes a noise.
Any clues ?
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Zombie
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That is exactly right.
It starts off with slow steady "thumps" as the pipe bounces off the bottom.
It will get crazy loud until the pots equalize in temperature, and then quite back down.
Just another thought... "suckback" might be the wrong term. Perhaps the "thumper" is not allowing vapor out fast enough, and pressurizing.
Be careful.
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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aga
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Suck-back is occurring from the thumper back to the boiling pot.
I just tried it again with 200ml, and violent suck-back occurred 6 mins after distillate started entering the thumper.
It appears that a very steady/constant heat is required to ensure a continuous positive pressure from the boiling pot.
I can't help feeling that suck-back is the 'thump' and that in copper pipes you just can't see it happening.
Perhaps with a few more practice runs it can be made to run as expected.
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Zombie
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Do you see liquid transfering from the boiler to the thump pot?
That could be the issue... Scale.
There should be NO liquid transfer. That is called "Puking" in distilling or "Bumping" in chemistry.
in forty years of distilling I have never once experienced any sort of "suck back".
| Quote: Originally posted by aga |
It appears that a very steady/constant heat is required to ensure a continuous positive pressure from the boiling pot.
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It is also possible that your hot plate is cyclic, and can not hold a steady enough heat.
We can not use hot plates in distillation boilers because they tend to switch off, and on in cycles rather than maintain a heat setting.
Try to avoid any sort of "puking, maybe boiling chips will help I do use them in even large boilers, and perhaps a water bath might help to maintain a
steady temp.
I know you will figure something out, and I really do appreciate your efforts here.
If I were to document any of this from MY end... It would be tantamount to a written confession.
I sort of like having access to daily life.
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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aga
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No liquid transfer ?
As the EtOH vapour leaves the boiling pot, it was condensing on the walls of the short transfer pipe into the thumper = liquid transfer.
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Zombie
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| Quote: Originally posted by aga | No liquid transfer ?
As the EtOH vapour leaves the boiling pot, it was condensing on the walls of the short transfer pipe into the thumper = liquid transfer.
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I see your point. This may be a scale issue combined with a materials issue.
Copper being much better at conducting heat will quickly reach the same Temp. as the containers, and greatly reduce or totally eliminate condensation
inside the pipe. What little does condense can simply roll / flow out due to the size of the plumbing.
I imagine you are having liquid actually fill the diameter.
The same thing may be happening on the outlet from the "thump" causing pressure to build inside.
Is there any way you could increase the diameters of the plumbing?
Perhaps a pair of mason jars / water bath boiler, and 1/4" copper tubing installed thru grommets...
Something else that might help reduce this would be a burner under the transfer pipe to keep it from condensing. Insulation would never be enough due
to the properties of glass. , ie: heat transfer.
Sorry this is getting so complicated.
[Edited on 3-19-2015 by Zombie]
They tried to have me "put to sleep" so I came back to return the favor.
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aga
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I came up with two possible anti-suck-back ideas: replace the thermometer on the stillhead of the boiling pot with a balloon, or turn the heat up
under the boiling pot.
The balloon would expand as vapour pressure increased, then would contract sufficiently to relieve the partial vacuum.
Amusing as that would be, i opted to just turn up the heat, which worked.
As i'm not drinking the distillate, the speed of the process is largely irrelevant.
Finishing off a Vigreux distillation, then i'll have the data for Standard, Thumper and Vigreux setups.
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aga
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Some Experiments Regarding Distillation Techniques
A series of experimental distillations were made to Quantitatively compare the effects of using a 'Thumper' and a Vigreux column in the distillation
of Ethanol/Water mixtures, specifically targetting the EtOH w% in the product.
The equipment used was all standard quickfit glassware, two thermometers, a kitchen timer and a refractometer (to measure the ethanol w%).
The thermometers were calibrated using boiling water, an ice slurry, and the standard y = mx + c formula along with a bit of algebra (to determine
slope multiplier and offset constant)
Ironically an ethanol spirit burner was used as the heat source.
The FeedStock for all experiments was 500ml of cheap 37.5 w% Vodka diluted with DIW to give 1875ml of 10 w% EtOH/Water (as measured by the
refractometer).
To determine the behaviour of a Thumper, a preliminary experiment was made with the apparatus seen here :-
250ml of feedstock was loaded into the boiling pot, and 150ml into the thumper.
Less than 1 minute after lighting the spirit burner bubbles (of air) were seen leaving the pipe in the thumper liquid.
@10 mins the liquid in the 500ml flask boiled.
@12 mins condensate was forming in the transfer piping, and entering the thumper.
@14 mins the liquid level in the vertical pipe into the thumper could be seen rapidly rising and falling.
@16 mins violent suck-back dumped the contents of the thumper back into the boiling flask.
@18 mins the thumper felt significantly warm to the touch.
@28 mins the first distillate product left the apparatus.
@38 mins distillate stopped leaving the exit pipe.
7ml of distillate were collected.
A second attempt was made with 150ml in the boiling pot, 50ml in the thumper.
The suck-back problem was worse, with several suck-back events after 16 mins.
These were prevented by removing the thermometer stopper as the suck-back developed, and so it was determined that the suck-back was caused by sudden
temperature drop in the boiling flask, which was in turn caused by the experiment being done outside in a light breeze.
A shield made from Al foil was devised to prevent this in subsequent experiments.
Logically, the thumper will heat faster with less mass in there, so a much lower volume was thought to be beneficial, so long as the inlet tube was
covered.
A line was noticed in the boiling flask, so this experiment was immediately aborted.
Turned out to be a just a manufacturing defect rather than a hairline crack.
#1 Thumper Distillation
190ml was loaded into the boiling pot, 10ml into the thumper and the flame lit.
After 36 mins 3ml of final distillate was collected.
Testing with the refractometer showed no result at all (off-the-scale).
The distillate was diluted 50:50 with DIW and this solution was measured at 49 w%, meaning that the actual product was 98 w% indicating some error,
probably in the dilution, as the azeotrope max is 95.6 w%.
The remaining 175ml of boiling pot liquid was measured at 4 w%.
The remaining 22ml thumper pot liquid measured 37 w%
#2 Standard Distillation (no column etc)
200ml FeedStock was loaded into the 500ml RBF boiling pot, and the flame lit.
After 10 mins 3ml of distillate had been collected.
This measured 76 w%
#3 Eleven-tier Vigreux Column Distillation
200ml FeedStock was loaded into the 500ml RBF boiling pot, and the flame lit.
After 16 mins over 3ml of distillate was collected.
This measured off-the-scale, and so was diluted 50:50 with DIW.
The resulting liquor measured 47.5 w% meaning 95 w% in the actual product.
Dilution error could have occurred as only 1ml of distillate was used.
Notes:-
In the Thumper distillations, the final product distillate was seen to stop after a certain time.
The experiment was stopped at that point, and the boiling pot had not yet begun to boil the remaining water.
It is suspected that more distillate would be seen after water began to boil and enter the thumper.
Suck-back is likely due to the similar volumes of boiling pot and thumper pot.
All photos seen of thumpers show them to be significantly smaller than the boiling pot.
Speculation is that the sheer volume of boiling liquid, and EtOH leaving the normal-sized boiling pot keeps up a positive pressure at all times,
regardless of the volume of the thumper contents.
More experiments are required to quantitatively determine the full distillation profile for the three techniques, such as total time, yield and w% of
product for a full run, and the w% of the product at set intervals into each run.
This set of experiments simply show that Thumpers do actually work in raising the w% of the product, at least in the early distillate product.
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Magpie
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Thanks for buying all this equipment and running this experiment.
I think your suck back is caused by condensation in the tubing between the pot and the thumper. Insulating shoud eliminate most of this. I'm sure
your aluminum foil helped a great deal.
Is that Spain or England. Looks very nice!
The single most important condition for a successful synthesis is good mixing - Nicodem
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Fulmen
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Interesting. I haven't had time to crunch the numbers yet, but this suck-back could explain everything. Since few of it's proponents has had the
opportunity to see it (metal construction), is it possible that this is the way they actually behave? If so, this provides the reflux needed to turn
it into a complete stage. Mystery solved?
As long as there is a reflux caused by suck-back it behaves in accordance with basic distillation theory. It's a simple single stage reflux stage as
far as I can tell. But I'll try to study the numbers a bit.
We're not banging rocks together here. We know how to put a man back together.
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