anyone out there try to make one of these things?
just ran across them on-line. i was absolutely
dumbfounded! now i'd like to try my hand at it.
although i have a pretty good idea of how to go about it,
none of the websites had detailed information. plenty of
sketches and concept drawings, but no real concrete info.
many years ago, probably in the 50's there was an article c/w detailed
dimensional plans in Popular Mechanics. I don't recall the issue dates but
will look further. As a lark we made a couple to see if it really worked
and found that if you ignore efficiency then they sure do work.
Back in the early '60s my teenage physics hero, Dr. CL Stong, published
a plan in the Amateur Scientist. I built it and it worked pretty well.
At the time I had no compressor so I had to test it at the Amoco
One of the first of many public displays that have earned me a
reputation for being, shall we say, a bit eccentric? :-)
t> anyone out there try to make one of these things?
"tony" wrote in news:EwEjb.298531$R32.9793629
I made one. I'm sure I still have the plans someplace. It worked, but it
used a lot of air. A WHOLE lot of air. It will chill a small box, maybe 15
X 30". I've never ran any long term tests, because compressing air to run
it isn't cheap.
Details matter with these things. If you get everything just right, efficiency
can be good. If you get anything slightly wrong, it won't. You either need
very detailed plans, or expect to do a *lot* of experimentation.
I have messed around with one of the commercial vortex tubes at work. It
wasn't that functional. It did provide cool air at one end and warmer
air at the other, but really not enough of the difference in temp. to be
that useful. I think that you'd get a better use of your compressed air
for cooling by using a higher volume right out of the hose rather than
creating a lot of extra noise and bypassing a lot of air for a 30-40F
degree temp reduction. Air consumption was all I could get out of a 3/8"
hose (10? cfm) for about 1 cfm of cool. And the noise was worse than
having a cut hose running all the time.
So for a fun project, go ahead, but I'm not convinced that they're worth
the effort for any practical uses.
Well ... I made one back around 1970 or so -- when I had very
little in the way of skills with the machine tools which I had access to
to make them.
I didn't have any dimensioned diagrams, I just took the
principles from the drawing which accompanied the demo unit which got my
attention, and it worked.
The main trick that I found was to make the exit end of the
large (hot) tube the same area as the hole in the center of the vortex
leading to the cold end. This balances things well enough to
demonstrate the principle.
The demo unit was part of a study to apply them to cooling
soldiers in tanks -- running the compressor from the tank's engine (or
perhaps from the electricity from the generator), piping the cold side to
flow into the tanker's helmets, and piping the hot side outside
somewhere, as there was no lack of heat in the belly of a tank. :-)
I don't know of any theoretical size limit -- but as a
*practical* limit, you will have problems getting enough airflow from a
home shop compressor to really demonstrate this with that big a tube.
You need a *lot* of air, even with the smaller ones. And be prepared to
wear hearing protection around it.
Again -- in a tank there is already so much noise that you
probably would not notice the vortex cooler doing its thing.
The October 1976 issue of Popular Science has an article titled "Vortex
tubes blow hot and cold" with directions on how to build your own simplified
version which came from a previous article in the November 1947 issue.
I have a set of copies, but I don't think a copy of these would be much
good. A lot of public libraries have old magazines on film that you can get
I have an automatic choke tester made by the Ford Motor Co. It has a Hilsch
tube which is connected to the shop air line and the output from either end is
fed into the choke spring housing to see if the choke will open and close.
A friend who used to be a steamfitter for the GN railroad tells me that hilsch
tubes were used in dining cars to heat and cool food.
Does anyone know of any other ways the Hilsch tube was used?
Actually the correct name is "Ranque-Hilsh Vortex Tube". The French
physicist George Ranque invented it in 1930. A number of uses have been
found for vortex tubes. Some of the more common are supplying small
quantities of cool/cold air for machine operations, cooling electrical
boxes, and laboratory experiments. It is also used for aerodynamic
separation of various gases. By cascading vortex tubes, this technology was
reportably used in South Africa's nuclear weapons program to separate/enrich
Uranium. Vortex tube cascades have also been used to liquidly gases. However
these last two uses are so expensive that only a government can afford them,
and if the technology is available, there are other more efficient and/or
less expensive ways of doing these things.
There are two types of vortex tube designs. They are the uniflow vortex tube
and the counterflow vortex tube. A uniflow vortex tube is closed at one end
with the warm/hot gas exiting around the valve at the other end. The
cool/cold gas exiting at the same end through the valve. A counterflow
vortex tube is open at both ends with warm/hot gas exiting from one end
around a valve and the cool/cold gas exiting at the other end. There is
little difference in efficiency between them if they are properly designed.
In both types the gas under pressure enters a cylindrical generator and
begins to spiral. The spiraling air can reach speeds of 1,000,000 rpm within
the tube. Without going into a lot of theory, and explanations as to how,
why, and what ifs, the gas near the inner wall of the vortex tube moves
faster than the gas farther from the wall. Heat is transferred from the
slower moving gas to the faster moving gas.
The valve that controls the flow of the warm/hot gas regulates the
temperature of the warm/hot gas or the cool/cold gas. The % of gas released
through the cool/cold exhaust is called the "cold fraction". Cold fractions
of 60-80% provide the greatest cooling; (BTUH) and cold fractions below 50%
provide the lowest temperatures.
At a pressure of 100 PSI and temperature of 70ºF, supplying filtered, dry
air, to 12mm vortex tube, can result in an output of cold air of -40ºF.
If someone wants to build their own I would suggest building a counterflow