# The Hilsch vortex tube

The hilsch vortex tube, cools and heats air at the SAME time with no moving parts, and NO electricity. cool huh? it's quite simple, and only a matter of getting the dimensions right! Not to mention the ability to produce EXTREME temperatures! all that's needed is compressed air!

So, let's demonstrate two simple scientific principles through this tube. That's right, two principles in one!

let's start with temperature. Temperature is an AVERAGE of how fast the particles are bumping into each other. Because it's an average, it means that air is composed of fast AND slow particles. It's hot and cold at the same time! (see right of third picture) How will this be proved? Well, I think that if we just separated the hot and cold, that'd do just fine for proving!

How's it going to work? By utilizing inertia! Which is defined as: "the property of an object to remain at constant velocity unless acted upon by an outside force." Basically, once you get a boulder rolling, it's not going to want to stop. And trust me, it'll resist you changing it's velocity!
There are two things that make up inertia- mass, and velocity. More of either means more inertia.

Now imagine, there's a wall that curves 90 degrees. A boulder and ping pong ball are rolling towards it. (see fourth picture for the explanation) now, as you saw, the pingpong ball was just pushed away with ease. Now, say the pingpong ball was the same size as the boulder (but still very much lighter) and on the right instead of the left. The boulder would still force its way to the wall. If you had a steady stream of boulders and giant pingpong balls, and this was a circle instead of just a curve, it wouldn't be long before there were only boulders rolling along the wall, and all the pingpong balls were all pushed to the inside.

Now, one step further, now because inertia = mass x velocity, say you had lots of molecules of the same weight going around that circle. But some were moving really fast, and others slow, because the faster ones are moving much faster (and have more inertia), they'll push the slower ones out of the way. (yes, just like the boulder and pingpong ball) and before you know it, there's the hot (fast) molecules around the edge, and slow (cold) in the center! (see left side of third picture) and that's exactly what the inside of the vortex tube looks like!

to put it very simply all the vortex tube does is get those molecules moving in one direction (rather then the chaotic right of the third picture) so that the separation will begin!

There ya go, you've learned two scientific principles, and the basic idea of how this machine works. If you want to know the history and a step by step process, go to step one! If not, and just want to build, just move to the step after that.

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ItsTheHobbs7 years ago
what does it do?
7 years ago
introThe Hilsch vortex tube
The hilsch vortex tube, cools and heats air at the SAME time with no moving parts, and NO electricity. cool huh? it's quite simple, and only a matter of getting the dimensions right! Not to mention EXTREME temperatures!
7 years ago
so its not productive its just............a..science project
thecheatscalc (author)  ItsTheHobbs7 years ago
Actually, it is productive, if you build it correctly, you can instantly freeze small samples. there are PLENTY of uses, just think what you could use cold air for!
7 years ago
ooooo ican think of two........ no offense, but its not to exciting
thecheatscalc (author)  ItsTheHobbs7 years ago
well, can't expect everyone to think it's exciting... thanks for commenting though.
8 days ago

I very greatly appreciate your work to publicize this amazing invention by Ranque and Hilsch. The key to the greatest inventions is simplicity, not complexity necessarily. This device piqued my interest when I first found out about it on the Internet (another great invention) back in 1997 approx. I believe it is a device with very great potential still waiting to be tapped. There have been comments to the effect that "compressed air" technology is inefficient. This is simply wrong, I think. Compressed air is an excellent means of storing energy. Standard methods of compressing air can be improved and made more energy efficient by one obvious method. Cadillac Aera "concept car" winner 2010, would use compressed air at 10,000 psi, and would get 1000 mile range (estimated). This is not "low tech" or "old tech" that has no current value; quite the opposite. It is so far in the future that people to this day have a very hard time grasping the fact that any vehicle can be powered solely by compressed air, running thru piston drive configuration or preferably rotary Wankel air motors (in-wheel hubs configuration, as used in the Aera concept car). EngineAir Australia Pty. Ltd. has made some good progress with this technology, but has been ignored by the investors needed for further commercialization. The Aera would be nearly silent in operation because rotary Wankel air motors do not "clatter" as do the piston configurations. So the technology is all available, but only needs to be systematized and put into commercial production (not as luxury Cadillacs, but as everyday, utilitarian vehicles, to include VTOL vertical takeoff and landing aircraft for everyday transportation, thus obsoleting roads, bridges and tunnels for personal transportation and everyday family errands etc.). Anyway thanks again for your excellent work on this Instructable and thanx also to Instructables.com, a great site that really gets the imagination going.

8 days ago

I forgot to mention that new air pressure tanks are available, made with "carbon fiber composite" and/or other high strength, lightweight materials. These amazing new pressure tanks make entirely new transportation systems feasible, whereas in the past, high pressure tanks made of steel were far too heavy to be practical for these applications. In the USA, a company called Quantum Technologies (QTWW stock symbol on Nasdaq) is or was making these high pressure carbon fiber composite pressure tanks, but may have been focusing on using them for natural gas or possibly for hydrogen storage, rather than for air pressure tanks; QTWW may also be involved in military applications that have limited commercial availability (this irritates me because it keeps happening to some of our best new tech). I am not sure what companies if any, are producing this type of tank for pressurized air specifically, or whether the fuel tanks can be used for air (most likely they can be used for any gas, although hydrogen can usually seep through almost anything). Anyway this is a bit off topic because the RanqueHilsch device can be used to assist in air pressurization, but that's not the typical use intended for it.

3 years ago
it works awesome as a coolling system on grinders
8 days ago

Also, just think what you could use hot air for. (And think what can be done with the difference between hot and cold, hint hint.) Yes, it is productive. Thinking it is not productive is what has kept it in the science museum all of these years. Henry Ford stated something to the effect that he "invented nothing," he just put together ideas and devices that had taken decades of peoples lives to develop over thousands of years. Thank you for the positive attitude here. We need to encourage invention, as you are doing.

8 days ago

"Just" a science project?? Please... Don't you think science can be "productive"?

5 years ago
But... don't you need an air compressor? that has moving parts right?
klaney1 year ago
Would it be possible to run this on something more continues, eg a fan blowing into the vortex chamber. It would be significantly weaker i assume but if you loop the hot air output back into the input it would increase/decrease the output temperatures respectively?
8 days ago

'Atta boy!

LamarS13 days ago

Would you mind sharing your feelings about a few things regarding vortex tubes? Firstly, what are the important dimensions you mention regarding effective vortex tubes? Secondly, do vortex tubes scale up well? If one were wanting to make a large vortex tube would they require air compressed to higher pressure, or a larger volumetric flow of compressed air? Thank you!

chuckdockery1 year ago
Thank you for sharing this. I used to use one of these in an automotive repair shop, it was much smaller and completely made of plastic. I cannot remember the manufacturer. I am now back into automotive repair and wish to use one of these again. In your plans you give a list of parts needed but in your schematic there are differences. The main difference is the length of pipe for the project. In your parts list it is 5" but in the schematic it is 24". Please tell me the length and why it needs to be this length. Thank you, Chuck
benbenbeng1 year ago
For non-relativistic speeds, inertia is not dependent on velocity, only on mass.
.
I doubt the air is reaching any appreciable percent of the speed of light.
.
Perhaps the intention was to reference 'momentum' instead of 'inertia'?
Otto Belden3 years ago
I have built several vortex tubes of different materials and sizes. There are a fun and interesting thing to build. The most successful one I made is here and is a bit easier to build:
I have instructions of how I built it along with a video and some thermal images I took with a FLIR camera showing the temperature gradients. The details of the other tubes I built are also there on my blog:
http://ottobelden.blogspot.com/p/various-projects.html
Scroll down to the Vortex Tube links. I'm more than happy to help folks build these tubes. Leave a comment on my blog or email me!
- Otto Belden
fidgety23 years ago
i have a quick question

on step 6 do you use the drill bit to "route" the holes for your air line and could you just clamp the 2 pieces of acrylic together and drill into the seam where they meet thus "routing" the air line?

thanks
fidgety2
xizero3 years ago
in my humble opinion the cooling is caused by the increase in velocity of the molecules without heating them - they will need to absorb heat to retain the velocity- and that will cool the inner slower molecules that don't need to because they are not moving as fast -- in essence i am proposing another law of physics one that if a molecule is accelerated that it absorbs heat to stay at its new velocity -- if such a law exists please excuse my ignorance as i am no physicist ... kind regards Mark
Randomm Science3 years ago
Can this be done with copper pipe to avoid any possible flammability that might be encountered with pvc?
atzi4 years ago
Interesting article in Vortex and on making one.
You explanation of a Vortex only separates the hot molecules from the cold ones I cannot disprove, but I have read of other theories like this one......

"While one airstream moves up the tube and the other down it, both rotate in the same direction at the same angular velocity. That is, a particle in the inner stream completes one rotation in the same amount of time as a particle in the outer stream. However, because of the principle of conservation of angular momentum, the rotational speed of the smaller vortex might be expected to increase. (The conservation principle is demonstrated by spinning skaters who can slow or speed up their spin by extending or drawing in their arms.) But in the vortex tube, the speed of the inner vortex remains the same. Angular momentum has been lost from the inner vortex. The energy that is lost shows up as heat in the outer vortex. Thus the outer vortex becomes warm, and the inner vortex is cooled."

I bought a Vortex Tube in the 1980's and used it to cool carburetor choke bimetal coils to test them and the choke linkage. Also was handy to cool temperature sensors to test their accuracy instead of waiting overnight or removal and install in freezer etc. Here is a video I did on my old Blue-Point Vortex. http://www.machine-history.com/Vortex%20Tube
ScienceWiz4 years ago
I am really determined to build one of these (I've wanted one since I saw it in a McMaster and Carr mag. but didn't feel like forking over 200 bucks for one) but I have a question about this step.

What exactly am I supposed to be dremeling? After I drill the holes and use the paddle-bit, what piece am I supposed to dremel and what am I trying to remove/smooth/etc.

Please reply if you get a chance, I would be very thankful!

And Great instructable btw, so far this is the only informational tutorial I've seen for making a vortex tube!
4 years ago
I think what he means is that you don't use the paddle bit to dig down and make the indentation for the washer. You use the dremel for that. Most paddle bits have 3 points, one at the center and two on each end.
| __ __ |
|/    \/    \|
Normally, when you drill into wood with them, the center point digs in first, then the two outer points dig in (and the circle appears), then the flat part digs in & starts tearing out wood. Here, the purpose of the paddle bit is just to dig the perimeter of the circle. You're only using those two outer points of the bit. At least I hope that's what he means, since I'm starting the project tonight.
4 years ago
That's the way I understand it as well. Although I do have a cheap and cheezy backup index of spade bits that don't have the scribe edges. They're not good for much though.
Morganbarker4 years ago
I have had on several occasions, the need for a 'stepped' bore similar to the above picture. One of the requirements was that the two bore sizes be concentric.

I find it easiest to start first with the large shallow bore so I still have material in the hole with the centering pilot from the big bit to target the smaller bit with.
apchar4 years ago
Do you drill into the wall of the PVC pipe? Doesn't the washer block the flow of air? It looks like it's right in front ot the air tubes. Are both halves of the MDF (er. acrylic) the same?
qokhan4 years ago
ScienceWiz4 years ago
I have a question about the Archamedes Design

In the picture, there is a weirdly shaped white space in the center of the design, is this supposed to be cut out? Left intact? or is the white space just unnecissary?

From the look of it, the Archamedes design looks like the Opposing jets but with only 1 tube (that is double the size). Other then the number of tubes leading into it, it looks pretty much the same. If you've had a chance to compare the 2, I would be really appreciative if you could share your findings, and also if you could explain the white space in the Archamedes design..

Thankyou!
And great instructable! Very informative and very well put together
Dutch_Razor4 years ago
The vortex tube is such a nice concept, in the lab we have an Exair Vortex tube (exair.com) which produces about 5 liter/s air at -30 degrees C.

It's so noisy that without mufflers, I suspect it goes above 120 decibels!
hiatus1385 years ago
"popular science monthly" magazine, may 1947, p. 144 had the article "homemade maxwell's demon blows hot and cold" in which plans are given out to make a Hilsch vortex tube. Required tools are just a drill press.

The plan specifies an input of 75 to 100 PSI
Output is claimed as "hot end too hot to touch, and cold end gathered frost."
A photo is shown with 2 thermometers reading 68 and 110 degrees respectively. the nature of the tube is that it is adjusted to maximize either heat or cold, you can't have both at the same time.

the entire tube is 12 inches long and made from 9/32" brass tubing.

Unfortunately, this issue is missing from Google book search beta, although all the other issues are there.

The article was reprinted in "mammoth home workshop manual" 1950, by popular science publishing. A great book, chock full of the sort of home handycrafts common in the "mens magazines" of the day. those WWII era magazines like pop. sci, pop. mechanics, mechanix illus. kinda seem to me like Make magazine's eccentric uncle.
4 years ago
www.popsci.com/archive-viewer

Pop sci just released their entire archive online (searchable by keyword).  Found that appropriately named article.
4 years ago

It depends on the settings. For maximum heating and or cooling temperature you can adjust the flow proportions. But for maximum heating and cooling btu's, (different than temperature) adjust for 50/50 flow, and indeed you will have heating and cooling at the same time.

jp_bosing4 years ago
From my understanding, the air that enters the Vortex Tube passes through some kind of generating device and spins at extremely high rpm's towards one end of the tube. Then an inner vortex of air spins towards the other end and exhausts as cold air. There is a real good flash animation at http://www.stream-tek.com/products/vortextubes/vortex-tube-works.php; gives a good visual on the inner workings of the Vortex Tube.

-- JP
billmc6 years ago
First go down to your local stream and build a "trompe" so as to supply your compressed air. Then apply the heated and chilled air from your Hilsch vortex tube to your favorite Sterling engine.
Pazzerz6 years ago
Here's a question fer ya.... You said in step 11: attach it to the air line (nearly close the ball valve) and slowly open and close the valve until the hot side gets VERY hot. Are you referring to the ball valve as the one you need to open and close, or is it on the air inlet from the compressor?? The two references to a valve has me confused a bit.
6 years ago
I think he means the one on the end of the pipe.
Rogue_ork6 years ago
would you need a "compressor", after all, you have no need to jam the air in permanently, could you just use a impeller or centrifugal fan? . After all, centrifugal fans can pump out a lot larger volume of air and are quieter too, they may not have the pressure capabilities of a compressor, but it may not need to.
servant746 years ago
I like this instructable. You might mention what volume and pressure you need to get 'acceptable' results. Even using your MDF, it would be OK for a while if you first take some wood glue, thin it about 50-50 with water, then use it to 'paint' the surface. That will fill in lots of the pores, make it smoother, and make it last longer in the presence of water. Do this even if you want to paint it. The glue makes a reasonable 'primer' for the MDF.
Kotazo7 years ago
I may be missing the stated use of this thing, but does it have any practical applications, or, is this a demonstration project for teaching science?
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