bling and tasteless jokes, we would be attempting
to channel Maxwell’s demon. They went for it —
though they insisted on keeping the tasteless jokes.
Using segments of iron plumbing pipe as the hot
and cold sides, I suggested that we epoxy together
a vortex assembly with three ½" slices of a Delrin
plastic 3" rod.
Revised Approach
The guys are not scientists or machinists but they
are talented, creative folks that are deeply interested in how things work. Hoping that would be
enough, the group reduced the vortex assembly
design to use a single Delrin disk. In my original
plan, the washer was replaced with a ½"-thick slice
of Delrin, but the revised plan brought back the
washer. We didn’t know if the thicker Delrin disk
would affect performance, but since we had no
idea what we were doing, we decided the fewer
changes, the better.
The finished vortex tube looks like a champion!
From appearances, it would seem to instantly freeze
tissue samples for plague research or, perhaps, cut
1"-thick steel plate with an awesome 1,000-degree
cutting flame! Real life offered slightly less spectacular results, but we did measure a temperature
spread of 8 degrees between the hot and cold
sides. We raised the flag and declared victory!
If I were a real scientist, I would continue to refine
the design using our modest success as a starting
point, but as an amateur, I am happy with the Proof
Of Koncept/Experimentation Revue results. Until
an engineer shows up with some imported spicy
salami, the vortex tube will sit on the shelf as a
memento of a fun late night with good friends.
Mister Jalopy referenced C.L. Stong’s collected
columns from the out-of-print The Scientific
American Book of Projects for The Amateur
Scientist, but the complete, 72-year archive is
available on CD-ROM (Scientific American’s The
Amateur Scientist, Science Fair Edition, $30,
brightscience.com).
AiRTX International ( airtxinternational.com) sells
commercial vortex tubes capable of generating
temperatures from - 40°F to 250°F. We thank them
for allowing us to use their superb illustration.
Mister Jalopy is an earnest but amateur scientist. Know
more about vortex tubes than he does? We wouldn’t be
surprised. Join us for vortex discussions at makezine.com/09/
vortex_tube, as we have lots of questions.
36 Make: Volume 09
Despite being hoodwinked, my friends met the vortex
tube challenge with enthusiasm and a determination
to succeed, provided the beer did not run out.
In the original “Amateur Scientist” design, adjustments
are made via the stopcock on the hot side and the interchangeable washer on the cold. (Source: The Scientific
American Book of Projects for The Amateur Scientist,
C.L. Stong, 1960)
Cold Air
- 40˚F (- 40˚C)
Compressed Air In
70˚F ( 21. 1˚C)
Hot Air
230˚F ( 110˚C)
Control Valve
AiRTX International, LTD. 2005 ©
AiRTX International’s commercial vortex tube ($109-
$149) produces frigid air from room-temperature
compressed air.
