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Distillation CondensersI have done a web interactive calculator to help with sizing condensers.Andrew advises ... One of the easiest ways to
increase a heat trasfer coeficient is to increase the velocity of
the fluids. Temperature of the cooling medium helps, but velocity
is MUCH better. This is why blowing on a spoon full of soup with
your breath (about 90degrees F) cools it off much quicker than
holding it in front of your nose, even on a chilly morning. What
I'm getting at is that close clearances are desireable, as you will
get lots of heat tranfer into your cooling water.
A good design, utilising this is Tom's version, used in a Nixon-Stone settup - see here for his diagram. If you're wanting to make a condensor coil, like the Nixon-Stone style ... Paul offers .. if you are going to bend copper,
get a tube bender. This is a wound steel spring that allows you to
bend tubing without kinks. Your hardware or plumbing supply can
help.
and John ... Spring-benders while they aid in
crude tube bending can be replaced with a die and mandrel type of
bender. This will yield uniform bends.These benders are available
from "Imperial Eastman Co." For larger diameters anneal the bend
area, cool,pack with sand and form over wooden die that has been
fabricated to match bend radius. This procedure will elevate the
finished product above the amateur level.
You just need to evaluate if the extra cost is worth the extra quality. Jack suggests .. A fancy mandrel type of
arrangement is easier to get than you might think - most people in
this area just wind the copper tubing around an old paint can. It
works a lot better than doing it by hand or with a spring tubing
bender. Past about one half an inch in diameter it gets to be a
little hard to do.
Another approach is to air cool the distillate. "Vonmantik" writes .. I had the fortune of befriending
an old distiller from the smokey mountains who had a ten liter
cooker with reflux tower. The unusual part was that he had designed
a air cooled condenser. It was made of about 25ft of 3/8 copper
tube coiled tight and centered in about 4ft of pvc pipe, on top was
a small box fan (from a recycled computer) that drew air through
the pipe. Intake was controlled by a homemade collar with allowed
the operator to contol air flow. This an idea that can be expanded
on it there is a problem plumbing water to the place you want to
set up.
Homer has a diagram of how he has fitted the coils into his reflux column. Click for a larger diagram :  Walter describes the "gattling gun" condensor ... I noticed that the N-S stills have
a coiled vapor condenser consisting of 3m of 5mm tubing through
which water flows, and from comments seems inadequate. What about
using a mini shot-gun condenser? On a typical 50mm diam. column
this would mean say a 300mm length of 50mm tubing, with a plate on
both ends with 12 holes drilled in a geometric pattern to take 12,
5mm open-ended tubes welded in place. It is still open to the sky
for safety. On the side there is a water inlet at the bottom and an
outlet at the top for the cooling water. In effect we have 3.6m of
vapor in 5mm tubing surrounded by cooling water rather than the
other way around. The unit can be welded on the top or attached by
a standard 15mm threaded plumbing connector so that it could be
replaced if necessary.
Brett has provided some excellent details on how to construct one, in a 2Mb pdf file: Making the Gattling Condenser
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