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Elninio
08-25-2010, 11:23 PM
Anyone tried making one of these? http://www.subtleenergies.com/ormus/research/Vortrap.htm

100PSI air in, -50Celcius and 200Celcius air out [aprox].

Edit: this seems like a bad idea as it consumes too much air - I don't think my rotary vane pump can handle it at all. Commercial models run as low as 2 cfm, but with 100psi minimum (my pump is 10cfm, 10psi). A better alternative that HSM'ers have concluded - for non-ferrous metals - would be to use ethanol mist. It's 15$ for 4L, but you're using it as mist ...

knedvecki
08-26-2010, 12:43 AM
I have used store-bought ones. They help, but not as much as a decent coolant.

JoeLee
08-26-2010, 12:46 AM
I've seen these advertised, just wondering how they work. A blast of compressed air tends to feel cool but I think there is more to it than that.

JL....................

Elninio
08-26-2010, 12:54 AM
I've seen these advertised, just wondering how they work. A blast of compressed air tends to feel cool but I think there is more to it than that.

JL....................

It creates a vortex; air molecules on the outside of the vortex have higher momentum ( mass x velocity), and thus are hotter. There is a wide outlet at the back (basically a hole almost-plugged by a cone), and a thin outlet at the front (washer). The thin hole allows only low-velocity molecules to exit, which are colder.

http://www.instructables.com/id/The-Hilsch-vortex-tube/ (intro)
http://www.erkim.com.tr/Vorteks_Tupleri.html (plan)

Black_Moons
08-26-2010, 01:12 AM
It works, but mine never did more then 0c output, and my second version did'nt even get that cold.

I think one of the really important things is you have a very smooth ID on the tube that is not disturbed by any connections, Basicly make the jets into the tube, don't try and solder on connections or make a seperate 'jet' chamber or anything fancy.

Ethonal mist sounds.. dangerious. Flamable.. explosive... and I don't think inhailing the denaturing ingrediants would be any good.

Elninio
08-26-2010, 02:52 AM
It works, but mine never did more then 0c output, and my second version did'nt even get that cold.

I think one of the really important things is you have a very smooth ID on the tube that is not disturbed by any connections, Basicly make the jets into the tube, don't try and solder on connections or make a seperate 'jet' chamber or anything fancy.

Ethonal mist sounds.. dangerious. Flamable.. explosive... and I don't think inhailing the denaturing ingrediants would be any good.

Its good for non-ferrous machining due to its high latent heat, 800F ignition temp, room temperature flash point, and Evan has even pasted a link to an article on using it as coolant high speed machining of aluminium.

http://www.mmsonline.com/articles/0706rt1.html

Evan
08-26-2010, 03:07 AM
Ethanol mist will work ok as long as you are only machining non sparking materials. It is used in industry for ultra high speed aluminum machining because it is a zero residue coolant and has excellent cooling properties. I wouldn't recommend it in a very small shop. Not because of an explosion hazard but because of the possibility of getting intoxicated. The usual denaturant is a bitterant oil in very small quantities and is non-toxic.

It should be used in a very minimal coarse wet mist and localized directly on the cut. It is often applied as individual squirts every few seconds. It isn't at all likely to produce an explosive atmosphere when used in correct quantities. I have used it for years and never had a problem. At room temperature ethanol will form an explosive vapor concentration but that tendency is reduced if using 95% ethanol in water instead of absolute ethanol. The main reason that it is quite safe is that it has a high autoignition temperature, nearly 700 degrees Fahrenheit.

In order to produce an explosive atmosphere it would need to be at a 3% concentration in air. If it got that high in the shop you wouldn't notice if it exploded. :D :eek:

darryl
08-26-2010, 03:17 AM
What is actually wanted here- a cooling system for the shop, or the experimental fun of a vortex cooler? If you're looking to blow cold air on a workpiece in the lathe or mill, the vortex cooler IS going to consume a lot of air. I think you'd be better off to come up with a coolant misting system with a high volume low pressure suction collection system. Of course, having a vortex cooler in your hand with hot air coming out one side and cold air out the other is- cool! I think it's worth exploring ways to make it more efficient, and consider how you could use it in the shop for heating and cooling parts simultaneously for press fits, etc.

JanvanSaane
08-26-2010, 04:14 AM
They do use a lot of air, I haven't used mine in a while. They were really handy for automatic chokes on carburetor equipped cars. Another note, they are very noisy with the air coming out of them. Jan

Elninio
08-26-2010, 04:30 AM
Where do you get 95% ethanol from? Everclear is prohibited in Ontario.

Evan
08-26-2010, 05:20 AM
I buy it at the local Save-On-Foods grocery store. They sell rubbing alcohol in the pharmacy section in two kinds. One is regular isopropyl alcohol but the other is pure ethanol. If the local mouthwash drinkers ever figure that out my supply is going to vanish.

Duffy
08-26-2010, 10:40 AM
I buy anhydrous ethyl alcohol at a company called Blended Specialty Chemicals in Ottawa. It IS denatured, but costs a bit over $12.00 for four liters.
The vortex cooler, aka Hilsch tube, was written up in The Scientific American back in the 50s or 60s. There they explained that, while it LOOKED good, it was spectacularly inefficient and therefore probably had little future other than as a curiosity. Of couse, there are ALWAYS exceptions, for example where the demand for "no moving parts to break" overrides the demand for "efficiency of operation."

Evan
08-26-2010, 11:37 AM
The Hilsch tube is commonly used to cool electronics that are stuffed into furnaces for direct sampling of molten materials.

I would bet that a vortex tube would be much more effective if run with argon or xenon.

ckelloug
08-26-2010, 11:43 AM
Take a look at http://itwvortec.thomasnet.com/viewitems/vortec/cold-air-gun?&forward=1

I've never used their cold air gun but I did work with their air amplifiers on a cooling project once.

--Cameron

bborr01
08-26-2010, 11:48 AM
I used to use one of these http://www.exair.com/en-US/Primary%20Navigation/Products/Cold%20Gun%20Aircoolant%20Systems/Pages/Cold%20Gun%20Aircoolant%20Systems.aspx for grinding.

I am guessing that they work on the same principle.

It would get below freezing and frost up the nozzle.

Brian

Elninio
08-26-2010, 03:18 PM
I buy it at the local Save-On-Foods grocery store. They sell rubbing alcohol in the pharmacy section in two kinds. One is regular isopropyl alcohol but the other is pure ethanol. If the local mouthwash drinkers ever figure that out my supply is going to vanish.

If the pure ethanol is in fact 95% ethanol, 5% water, aren't you afraid it could rust up your bed ways? In ontario you need to get all sort of documentation before they'll let you buy pure ethanol!

noah katz
08-26-2010, 03:20 PM
I used to use one of these http://www.exair.com/en-US/Primary%20Navigation/Products/Cold%20Gun%20Aircoolant%20Systems/Pages/Cold%20Gun%20Aircoolant%20Systems.aspx for grinding.


The Exair was sounding pretty good until I saw that it uses 15 SCFM; that would keep my 5 HP compressor running continuously.

Duffy
08-26-2010, 07:03 PM
DRINKABLE pure Ethanol may be difficult to get, but DENATURED, (non-drinkable,) is no problem. The denaturant is not intended to kill you; rather you are supposed to (barely) survive and spread the word not to drink the stuff. Anhydrous ethanol has no water, (at least until you leave the lid off the bottle for a while.) Common ethanol is about 96%, the rest being water. That is the highest concentration it can be distilled at since it is an azeotropic, (constant boiling,) mixture at that concentration. The drying process to remove the last 4% water probably leaves a nasty residue that constitutes the denaturant.

Evan
08-26-2010, 07:07 PM
If the pure ethanol is in fact 95% ethanol, 5% water, aren't you afraid it could rust up your bed ways?

The water is chemically combined with the alcohol and evaporates with it as well. Besides, I oil my machines. :D

BTW, they dry ethanol by filtering it through unslaked lime. It actually makes it more pure as well as removing the water.

Mike Burch
08-26-2010, 07:47 PM
For an explanation of how a Hilsch tube works and how to build one, see http://www.visi.com/~darus/hilsch/index.html#fig235