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Saturday, September 5, 2009

DIY Homemade Ranque-Hilsch Vortex Cooling Tube

Nothing really says Labor Day Weekend to me like a homemade vortex cooling tube! Well maybe not... but  I always wanted one and they really aren't that hard to make. I built one in one afternoon in the garage from PVC pipe, glue, a few tube fittings, a adjustable clamp and some sawing and filing...  The cool thing about them is there are no moving parts or high tolerance dimensions to hold when making your very own vortex cooling tube! All you need after building it is compressed air to get it to run and you get hot air out one end and cold air out the other. Here is how I DIY'ed a cooling tube and a little bit about how they work. The first picture below is what I ended up with. You can get anywhere from 10deg C to 70deg C cooling with these kinds of devices. I got about 15 C with mine but I bet I could get more if I tinker with it a bit.
UPDATE 8/28/10: I have added some videos explaining how I built this HERE!!
Check them out! 
  
Finished Vortex Cooling Tube
UPDATE 7/8/11 I made a smaller Vortex Tube and got much better results and posted info about building it HERE and well as a Video covering the construction HERE. I also created a Vortex Tube FAQ page HERE have a look at those pages if you are interested in building a Vortex Tube or if you just want to know more about them. Questions / Comments? leave some comments or email me at ottobelden@yahoo.com !!
   
These devices have been around for a long time and have some practical uses in industrial applications from sewing machines to welding. The principle of operation is that compressed gas at a significant pressure is sent into a tube through tangential holes or nozzles somewhere near the middle of the tube. Essentially these holes are going into the tube "right on the edge" so that when the gas enters it creates a 'swirling vortex' of gas. Sounds high tech!!! The gas swirls down the tube and there is a separation process due to the kinetic energy in the gas and you end up with cooler gas in the center of the tube and hotter gas on the outside. The cooler region can be and usually is cooler than the gas that entered the tube through the inlet nozzles.
  
  
Cross Section Sketch of What is Going on Inside

Here is a crude hand sketch I did of what is going on inside. The gas is going into the tube on the left hand side of the drawing through the holes labeled Inlet Air. The green spiral shows the gas swirling to the right where it runs into a conical shaped block that can be adjusted in and out of the tube. When it hits the cone the hotter gas is siphoned off around the outside of the cone and the cooler continues to spin back down the inside in the other direction. When the cooler gas makes it back to where the nozzles are it reaches an orifice in the tube that allows the cooler gas to exit out the left side in the drawing. The orifice is there to let the cold gas out but also to facilitate getting the inlet gas swirling and traveling in the correct direction (to the right in the picture). Adjusting the cone shaped block in and out allows you to adjust the ratio of how much air is going out each end of the tube - balancing the flow - and changing the temperature difference between the hot and cold ends.

To build my vortex cooling tube I used PVC pipe that has an inner diameter of about 0.81 inches. Looking into the formulas for the design of a "real vortex cooling tube" you usually want the length of the Hot End of the tube to be about 45 times the diameter or in my case about 36.5 inches. So this is the length in the drawing above from the inlet nozzles to the cone block valve. In keeping with that thought here are some other dimensions that I followed in making my tube:
  
Tube I.D. = 0.81"
Hot End Length = 45 x 0.81 = 36.5" (round off a bit)
Cold End Length = 10 x 0.81 = 8 (round off a bit here too)
Orifice Size = 1/2 Tube I.D or about 0.40 inches (ballpark rounding of slide rule accuracy)
Inlet Nozzles = 0.12" and I drilled 5 of them
  
Vortex Chamber

A close up view of the "vortex chamber" as I like to call it - this is where the Inlet Nozzles and the Orifice are. To make this part of it I took a piece of PVC tube and cut it to make the Hot End Length and the Cold End Length to the dimensions above. (Scroll down to a hand drawn picture of a cross section when reading this part to help see what I'm explaining) Then I got a thin piece of plastic and cut it into a circle the same diameter as the Outside of the 0.81 I.D. PVC tube -  the outside diameter was about 1.05 inches (so 1 inch tube). I drilled a hole in the plastic about 0.40 diameter to make the orifice. I then got a 1" PVC pipe tube coupling and filed and sanded the inside so that the PVC pipes will slide all the way through. I slid the Hot and Cold tubes into this coupling capturing the cold Orifice plate in between - no glue at this point.
  
Orifice Plate

Above is a picture looking down the cold end of the tube at the orifice plate. You can see the 0.40 diameter hole. I marked the Hot and Cold tubes as well as the coupling so I could take it apart and put it back together in the same orientation.... then I took it apart and glued in the hot tube only. Next I drilled 5 holes through the coupling and into the tube at an angle (tangential) as close to the end of the Hot tube as I could.
  
  
Actually I had my assistant Otto Jr. help me drill the holes! The drilling was made easier bu starting the holes with an Exacto knife.
 
  
UPDATE 8/28/10: I have added some videos explaining how I built this HERE
Check it out!
  


So now the two 1/4" cut pieces (red in the picture above) form the ends of a chamber labeled Inlet Air Area with the large 2" pipe coupling making the outside (Purple). All this is to have one inlet fitting for the air to go into the Inlet Air Area and from there it can make it into the 5 Inlet Nozzles. I could have had just one inlet nozzle or have five air lines into each hole but the method above works better and is super fun to make! I drilled one hole in the outer coupling and screwed a 1/4 Tube X 1/4 NPT fitting into the PVC plastic. I applied a lot of PVC glue and drilled the hole small so the fitting cut it's own threads going in.
  
Now onto the other end of the vortex cooling tube. The cone block I turned down on my homemade lathe and glued a bolt into it. The bolt threaded into the end of a DeStaCo clamp that was run through a PVC pipe plug. I cut a notch in the tube to let the hot air out and drew graduations on the cone to get an idea of how much adjustment I'm getting when I move the red lever.
  
Here is the cone block valve installed in the end of the tube.
  
That's about all there is to it! I attached an air hose to the tube fitting I screwed into the side, put on my safety glasses and turned on the compressor. These things make a lot of noise and get pretty warm / cold on their respective ends.
   
Be sure to take a look at THIS link to see some of the other Vortex Tube related things (and other stuff) that I have built.
   
For another cool version of a D.I.Y. Ranque Hilsch Vortex Cooling Tubes and lots of good information click HERE
   

32 comments:

  1. Excellent information on how to make your own Vortex Tube Otto!

    If someone reading this is looking for some technical information along with animations, FAQs, etc. We would like to invite you to look at https://www.stream-tek.com/products/vortextubes/vortex-tube.php.

    --
    STREAMTEK Corp.

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  2. I'm one of those guys who learns through visuals. it will be really great if you could make a video (youtube perhaps) of this. i really need to make one of these for my job nature. i work in an enclosed space almost 60 percent of the time in one day. it gets pretty hot in there. you will be a real life saver.

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  3. Anonymous,

    Thanks for checking out my blog! I will do a video if I make another Vortex Tube but I don't know when I'll do that.
    If you want to email me with any questions you have at ottobelden@yahoo.com I'd be happy to provide as much detail as I can. There is not any real magic to it but it does take A LOT of air and I mean A Lot to get good cooling. Check out the site I link to above
    or here:
    http://vortex.etailcentral.com.au/index.html)
    for more information and ideas about how to build these.
    Jet me know if you have any questions!
    Thanks again - Otto

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  4. thanks for responding right away brother. the rest of the stuff i can pretty much figure out. it's the vortex chamber i'm having problems with. that's where i start going "HUH?". if you could add some more pictures with a little bit more of detail on how to do it (vortex chamber), i'll add your name to my "nice" list for christmas. thanks brother. i'll be waiting for that video.

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  5. Anonymous,

    Sure, I'll add some (a lot) of detail to explain exactly how I made my vortex tube. Check back soon and I'll have all your questions answered in a new post - I'll update this post as well with a link.

    - Otto

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  6. Anonymous,

    I have made a couple of videos detailing how I made the Vortex Cooling Tube "vortex chamber". I linked to them in the above post and you can also go to "Pictorial Index Of Projects" page at the top of this blog and scroll down to the vortex tube for a link. Or here:
    http://ottobelden.blogspot.com/2010/08/updateed-diy-homemade-ranque-hilsch.html#more
    I hope they answer your questions, if not let me know. Enjoy!
    - Otto

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  7. otto, are there any significance on the length of the hot/cold tube? will the cold air be reduced if it's shorter than what you have in your instructions?

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  8. kokok sparky,
    I'm glad that the videos help you! Yes the dimensions of everything are important at least relative to each other. There are suggested ratios to follow but nothing is really "for sure". You can make the lengths shorter but also make the chamber smaller and the tubes smaller in diameter in other words. Vortex tubes make both hot and cold air and they don't make much of each relative to how much air you put in them - and you have to put in a lot of air - and I mean A LOT of air.
    Building a small one might give better results and usually these are used for "spot cooling" in welding and machinery like cooling small areas. Not sure how well it will work for what you want but give it a try and let me know! Vortex tubes are also really noisy.
    I recommend you read everything on this link:
    http://vortex.etailcentral.com.au/index.html
    And read this PDF:
    http://www.thaiscience.info/Article%20for%20ThaiScience/Article/3/Ts-3%20investigation%20on%20the%20vortex%20thermal%20separation%20in%20a%20vortex%20tube%20refrigerator.pdf
    Good luck and let me know how it works out for you!

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  9. kokok sparky,
    For sure check out the PDF I linked to above in Table 1 they have ratios of dimensions that should help if you are going to scale your tube down to a smaller size or up to a bigger size.
    Another thing I have been thinking about trying is making the 'valve' at the hot end less pointy - with more of a flat on the tip instead of coming to a sharp point. Might give better results.
    Cheers,
    Otto

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  10. Just watched your videos - thanks for sharing your information! :-)

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  11. for the one you made, how much compressed air pressure do i need to get it to work properly? we use about 90 PSI low pressure air @ work. is this enough?

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  12. Sparky,

    I used a compressor at work to get the best results. I don't know what the total flow was but the pressure at my work max is 135psi. I don't remember if I put that much in - be careful!

    Otto

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  13. Hey Otto,
    I'm a French science studient and I chose vortex tube as my project for this year.
    First I would like to thank you for all your details, it's a pleasure to see how you're involved in this How To article.

    I think you're going to receive a lot of messages from me as I plan to build my own vortex tube.

    In order not to take any risk, I'll use exactly your dimensions.
    So my first question is : where did you find your cone block ? Is it homemade ? Sorry if it is said in the text, actually I don't get the whole of your explanations.
    Would you please take my e-mail so that your blog is not flooded by my posts ?
    My address : theo.mathurin@gmail.com
    Theo.

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  14. Hello Theo,
    The Cone Block" I made on my homemade wood lathe. I don't think it has to be a cone shape, a dull point or disk will work.
    On the right near the top of my blog under "Sites I like" is a link to "DIY Vortex Tube Info!" that site has a TON of info - check out the links he has there. Did you watch my videos as well? What kind of compressor do you have? I'll send you an email... comments are OK too!
    Good Luck with the project!
    -Otto

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  15. Otto, thanks for the wonderful job and details. may i know what were the inlet(compressed air) and outlet(cold and hot exit side) pressure and temperatures, if u've measured it for various valve open settings.

    -Abhay

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  16. Abhay,
    Thanks for the compliment, I'm glad you find my blog useful. I don't know what the inlet and outlet pressures or flow rates were with this tube.
    I built a smaller tube not too long ago:

    http://ottobelden.blogspot.com/2010/12/another-home-made-ranque-hilsch-vortex.html

    That tube had better results and I was able to take better measurements of inlet temp/pressure and outlet temps. I don't have a rotameter to measure flow rates :( and measuring the pressure of the outlets might cause back pressure and mess with the performance? Not sure...
    Are you building a vortex tube? I'd be interested in seeing it. Check out my other post linked to above and let me know if you have any questions!
    Thanks again,
    - Otto

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  17. thank you so much Otto for the quick response to the query. yes i do like to try make an experimental vortex tube at home sometime with a few modifications at the cool end to mix two air flows to increase flow rate on the cold side. not attempted anything this before just because of curiosity of cooling a small chamber inside the room/house.

    thanks again for ur kindness and help would go through the links also that u've provided.

    cheers,
    =Abhay(India)

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  18. Abhay,
    Good luck with your project, if there is anything that I can do to help let me know. You can email me at ottobelden@yahoo.com
    Please be careful with compressed air, wear eye protection and take precautions.
    I'm interested to hear how well your vortex tube works. Send some pictures if you can!
    - Otto

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  19. What type of compressor were you using? I have a 1/4 hp compressor that can reach 70-80 psi. Is this alright for a Vortex Tube? Thanks!

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  20. Omar,
    Thanks for checking out my blog!
    I think that 80psi will work if the tube is smaller than the one in this post. Have a look at this post about a smaller tube I made:

    http://ottobelden.blogspot.com/2010/12/another-home-made-ranque-hilsch-vortex.html

    The flow rate of air is really important and usually what prevents the tube from working. Being able to keep up around 80psi with such high flow requires a big compressor. For this tube I used a big industrial compressor, unfortunately I don;t have a way to measure flow rate :-(

    - Otto

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  21. Thanks! I have tried making one, with 1/2" pipe, but in the initial test, it didn't work. I think I had some mistakes with the chamber. I think it's with the inlet holes and the orifice. Will have to check it again, or make a new one. Thanks!

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  22. Omar,

    No problem, if you send me some pictures or a sketch of what you built maybe I can help with some suggestions.
    ottobelden@yahoo.com
    Thanks for checking out my blog!
    - Otto

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  23. Hi, I am now able to use a larger compressor, a Bebicon 2HP compressor (6-10kg/cm^2). Do you think I can now use a larger pipe for the vortex tube? Like a 3/4" or 1' pipe? Thanks!

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  24. Omar,
    That's probably enough pressure for a 3/4" tube, but what is the flow rate the compressor can maintain? The flow rate is what always got me when building larger tubes I could get a high pressure but a compressor that can deliver the pressure and keep up the flow rate at the same time was a problem.
    Have a look at this post I did here if you haven't already for general questions:
    http://ottobelden.blogspot.com/2011/06/homemade-ranque-hilsch-vortex-cooling.html#more

    What are you trying to do with the vortex tube? What are you trying to cool? A smaller diameter tube might be OK for what you are doing.
    Thanks for checking out my blog!
    - Otto

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  25. If I'm not mistaken I think the compressor is capable of pumping 257L/min of air.

    I am trying to build a vortex tube for use in the machine shop, where we can cool hot metal objects.

    Thanks again! :)

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  26. Omar,
    If your compressor can maintain that flow at the pressure you mentioned I think you'll be OK.
    This is a guesstimate but I wouldn't go any bigger than 0.5" inner diameter on the tube. I would start with two inlet holes 0.31" diameter to start with and see what happens. Be able to open the holes up a little after testing it. Commercial vortex tubes running near what your compressor can do (100psi / 8 SCFM) can achieve 400BTU/hr.
    I think you will have good results for spot cooling once you get the tube built. If you take some pictures of diagrams of what you build I'd be interested in seeing them! email me!
    As always be careful with compressed air, use clean dry air in the tube for best results and to avoid the tube getting clogged. Wear eye protection etc...

    Good Luck! I'm looking forward to seeing what you build!

    - Otto

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  27. Thanks again! Will update you as soon as I get some plans ready! Thanks!

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  28. Awesome job Otto! I appreciate the very fine "make shift" engineering to make a quite sophisticated instrument.

    For experimenting, I think I will try not gluing the cold side tube into the coupling to give access to changing the "restriction washer". Maybe I will use tape to secure the cold side tube in place.

    Thanks for sharing Otto, great job.

    Filter
    .

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  29. Homemade you say? Amazing job otto. loved it

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  30. air conditioning utah,

    Thanks!

    Otto

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