Hilsch vortex tube

[Stealth]

Has anyone built or bought a Hilsch vortex tube. You can go to Instructables.com and download plans for a simple version of the original. These were used during WW2 by the Germans to heat subs during their North
Atlantic campaign. Several companies now build these, mainly for industry.
Stealth

[Electrotek]

I've built some of these. They're actually called Hilsch-Rankine tubes. I made a small one with three pipes, one as the input and two outputs. When I blew into the one going into the single turn spiral, I could definately feel hotter air coming out one pipe and cooler air coming out the other.

I also did an experiment once to see if it would separate gases based on their weight. I figured if hotter particles swirl to the center and go out the smaller washer's hole on that side, lighter gas molecules should also float towards the center. I built one of these to fit on my tailpipe, with a 3/8" plastic tube running from the 'hot' output back to the manifold vacuum. I took it to the emissions garage, and I was getting .2% CO from my old engine. Then, with the tube slipped over the tail pipe, the CO dropped to .02%.

The next thing I noticed was that the plastic tubing started filling up with little plugs of water about 1.5" long, every couple of feet or so. It seems the water vapor was also a lighter particle, and was going out the 'hot' side. So I abandoned it.

I'm planning to build a larger, fan powered unit, with a small computer fan on the output. Hopefully, this'll put the hot humidity outside, and leave the cool dry air inside. Never again am I going to pay a huge light bill to run an air conditioner!

If one of these is big enough, it might work as an atmospheric still.

[Guest]

Thanks! Great interest in this one, I am an AC expert!

[Electrotek]

One more detail I remember, but which I didn't incorporate is that the larger diameter pipe on the side with the larger washer ideally would have a damper. I believe you AC guys call it a VAV. This allows the pressure to be ballanced so that the ratio between the sizes of the two washers doesn't have to be perfect.

Mine worked because I'm an artist and everything was harmonious.

[Stealth]

I have built 2 of these to experiment with. The first didn't work very good. The next one worked better, but still I had trouble getting it very hot. Maybe I was expecting too much, but I talked to a guy on another forum who heated his house with a large one. I know the vortex principle is sound. The actual blueprints from the Ranque-Hilsch tube were pulled off the internet 3 years ago by American Scientists. I downloaded and copied it before then. I have an ongoing experiment/relationship with this tube. Trying to improve on an already ingenious invention.
Stealth

[Electrotek]

I experimented with this about 25 years ago. What I remember from that time is that the temperature difference was related to the pressure input. Best results used compressed air, I think around 120 psi, with a fairly small tube. And the nozzel on the output side spun rapidly, to help establish the inner vortex.

[Bob Smith]

I find this topic fascinating in light of what I've read of Viktor Schauberger's work in vortex technology. I'd be interested in seeing some plans or a link to plans if any are freely available, or if anyone's able to share.
Bob Smith

[amigo]

Electrotek,

It sounds to me that if we could generate a differential in pressure at the input, normal atmospheric pressure vs vacuum for example, we could achieve good results. I say this because it seems to me that the input of compressed air throws off the energy balance so that much more energy is consumed than produced to maintain the pressure. If we could have a minimum investment in energy at the input and somehow get the Nature to supply the rest, it could be worth while?

Of course how to cheaply generated vacuum to have these pressure differential at the input is still beyond me... I sort of see a set of vacuum chambers that would open in sequence but also get escaped in sequence too, so that we have a constant pressure difference.

[Electrotek]

Hi amigo,

I've had the same idea about the differential in pressure, although not with an actual vacuum. More of a fan on the input and a smaller fan providing suction on the 'hot' output.

I'd start with a spiral made of cardboard. For instance, it could be two feet in diameter and two feet wide. The cardboard would curl around, making one complete turn, while the diameter gradually decreased so that the inner end of the cardboard would be around 8" in from the starting end. Both sides would then be covered with flat pieces of cardboard. On one side, there would be a one foot hole, and on the other side, a 4" hole, with both holes centered on the inner part of the spiral. Then there'd be some kind of pipe on each side, the same size as the holes, and about two feet long.

With this design, a gentle swirl is all it would take to seperate the temperatures. This can be seen by holding a cup of hot coffee in the freezer, then moving the cup in a small circle. The steam will be visible, and the gentle motion can be seen to swirl the steam into the center.

So with the cardboard vortex tube, a slow moving fan, or even the wind, would set up the swirling air inside. The hotter air, and the humidity, would float to the center of the swirl, where a small fan's suction would pull it out. The cooler air on the outside of the vortex would go out the larger hole. (Pointing down?) The internal pressure could be ballanced by putting a round baffle in the larger pipe. By turning the baffle to the right angle, the back pressure would be just right to force the center of the vortex out the smaller hole.

And of course one of these could be made bigger or smaller, using the same basic proportions.

I wonder how effective it would be to power this with nothing more than a spinning shaft positioned through the center of the two holes? To be in harmony with nature, the end of the shaft sticking out the smaller hole would turn counter clockwise, looking along the shaft at the hole, while the other end would turn clockwise, looking along the shaft towards the larger hole.

Interestingly enough, the large hole on the side can be used as the input. The air will still swirl around, with the hot air coming out the small hole and the rest out the opening in the spiral. This is something I discovered myself.

So your idea of using a vacuum, or reduced pressure on the output and normal atmospheric pressure on the input might work. With the input on the bottom 'side' and a periodic vacuum applied to the small hole on top, the atmosphere's inertia might keep the air flowing long enough to set up the swirling.

[Stealth]

Hilsch vortex tube

If you would like to see what is left online by the Scientific American on this, go to www.visi.com/-darus/hilsch/ These are partial diagrams of the patent. I
hope this gives you enough info to build an experimental tube. I have thought also of powering mine with a squirrel cage fan, but have not had a chance to try it. Volume of air should work with a vortex system.

[Electrotek]

A squirrel cage fan would be ideal for this application. A two foot spiral only has to be as wide as the input pipe.

A squirrel cage fan has a spiral of its own. This might work as the frame for a vortex tube, if it were powered by a long, thin blower from a hand held hair dryer. Only one brand has this type of fan, but the thrift stores have them sometimes. Paul Masoon or something like that. The little motor is 12V DC.

[Alana]

Hi everybody,

very interesting posts.

@Stealth: you link does not work: www.visi.com/-darus/hilsch/ ???

Please note: there are several companies out there who deal with this kind of tubes (also with some calculations):
1. Vortex Tubes at AiRTX International
2. AX-Gen-Daten (in German language, sorry).

Regards
Alana

[Stealth]

I tried the website again and it didn't work, so I retried it and found this is the correct website THE HILSCH VORTEX TUBE Try this. Sorry for the
inconvienience. Maybe this will work for you.
Stealth

[Vortex]

Some links to look at vortex tube
Like the vortex tube, no moving parts Pulse-tube Refrigerators
Pulse tube refrigerator

[Jetijs]

So what would the best ratio of small hole diameter vs. big tube diameter and tube length be? Why do we need adjustable valves? To adjust the time the air has to separate into hot and cold flows?

This video looks great, especially the cold air "flame"
YouTube - Rank-Hilsch vortex tube