Homemade Bladeless Fan Construction and Testing - DIY Dyson fan

Some time ago I decided to build myself a bladeless fan like the Dyson Bladeless fan you see in the stores and on TV. These things look really neat and I would like to have one but unfortunately they cost a lot of money. Before going 'full tilt' and trying to make a really big one I thought it might be a good idea to start with something small, after all that should be easier right? As with most of the projects that I attempt I'm never really sure if they are going to work so I didn't want to put a lot of effort into making one - in other words keep it simple.

  

From what I have seen and read it's just a airfoil shape that is wrapped around into a ring and you blow air into it through a small annular gap around one end. The air is blow through the gap using a fan that has blades so is it really a bladeless fan? The air going into and through the ring draws more air in from behind the ring and around it so you get a lot of airflow - at least that is how it is supposed to work!! HERE is a link to a video of the inventor Sir James Dyson explaining how it works better than I ever could. Below is how I went about making my own small one and a exciting video of it running!

  

Beginnings of Fan (pieces of parts)

  

Rather than trying to construct the ringed airfoil shape from scratch I figured I could find something pretty close to the shape I wanted. So I wandered around the local dollar store until I saw some really cheap ($1.00!!) plastic drinking glasses. I bought 2 of the 4" diameter drinking glasses and one wine glass ($3.00 bucks!!! The math is so easy in the dollar store!!). The 4" diameter and the smooth change in diameter is what caught my eye. Here is what I did with them.


UPDATE: I made a video showing how I built this fan! Check it out by clicking HERE

  

In the picture above you can see a plastic glass on the left with a green line drawn across it labeled Step 1. The reason it's Step 1 is because I cut one of the glasses right about where the green line is to get the piece in the middle of the picture. In the picture the piece in the middle doesn't look quite right because it's flaring down to a smaller diameter in the middle and then it gets bigger. More about that in a second.

  

When I cut it off the plastic drinking glass ring it just flared out like the plastic glass in the picture. After cutting it off I then cut the bottom off the wine glass (right side of the picture). Then all I had to do was take the ring from the glass and put it onto the wine glass, pressing it down as far as it would go, which wasn't far! - Step 2 in the picture. Using leather gloves to protect my sensitive hands I turned my paint stripper heat gun onto it until the plastic ring from the drinking glass got all gooey and soft. At that point I could  carefully form the heated ring down onto the wine glass and give it that double flare shape. Using the wine glass to shape the ring is important and will be obvious below.

  

Once I had the drinking glass ring shaped to the wine glass operation done I performed Step 3 in the picture and cut the wine glass right about where the green line is. That gave me a wine glass ring that fits really nice into one side of the drinking glass ring. These two together will make the business end of the bladeless fan.

 

Bladeless Fan Ring Construction

  

The next step was to take a piece of clear (or any color) 1/8" thick plastic sheet and cut it into a doughnut shape. The outer diameter of the doughnut is the same as the final heat gun flared end of the drinking glass ring. The inner diameter of the doughnut ring is a little bit smaller than the wine glass ring. I glued the wine glass ring using Loctite Super Glue onto the doughnut shaped plastic and sanded the inner diameters of both of them smooth so they blend in really nice.

  

At that point I glued the wine glass/doughnut onto the end of the drinking glass ring positioning it as concentric as I could. The Loctite Super Glue Ultra Gel is like a mixture of super glue and rubber cement. It's sticky and gooey and seems to fill in cracks and voids really well. The downside to using it on thermoplastics is it causes really bad crazing. That shows up like a white frosty look to the plastic and a lot of it is caused by the adhesive outgassing so it goes everywhere, not just where the glue is.

  

Anyway this is a functional project and aesthetics is not an issue. That is what I always say when something I built turns out crappy.

   

Homemade Bladeless Fan Ring

At this point all I had to do was cut a clear plastic bottle that was the right diameter and glue it all together. I cut a hole in the side of the plastic bottle before I glued it so there would be a place for the air to go in. The wine glass ring is positioned so that there is a really small annular gap between it and the drinking glass for the air to come out.

I attached this 'fan' to a cardboard tube and placed a small PC type motorized fan in the end of the tube to push air into it. The whole setup was then suspended in front of my 8" parabolic mirror that I use for Schlieren photography with the cardboard tube on the top. You can see it in the video. The Schlieren system allows me to see the airflow around the fan to get an idea of how well it's working (or not working as the case may be).

  

Below is a video of the fan running with the ring in the middle of the picture and the cardboard tube coming down from the top. You can see the airflow coming out of the ring on the right side and also air being drawn in from the left side of the ring once it starts running. It looks like I also might have a little leak in the cardboard tube as well.

 

Homemade Bladeless Fan Test

   

To me it looks like it is working pretty well from what I can see. There isn't a huge amount of air being drawn into the ring but I think that there is enough that I will continue to mess around with this. From just an airflow standpoint it doesn't feel like there is a lot of air coming out of it compared to the fan that is blowing air into the cardboard tube. That isn't surprising because axial fans with blades (like a PC fan) are not really good a pushing air against a resistance or backpressure. The 'real' bladeless fans that you can buy have an impeller style centrifugal fan that can really push a lot of air through the tiny opening in the ring. That would be the next thing to try. Getting rid of the cardboard tube and using something that doesn't leak would be a good idea too!

 

Second Test Video of my Bladeless Fan Ring

Above is another test video I did. Toward the end of the video you can see a change in the airflow. That is because I have an inert gas mixed in with the air to help see the flow. At that point I increased the gas flow and I think the fan slowed down for a second when that happened.
  
Be sure to check out the Site Index of Projects to see some of the other things I have built.
  
That is all there is to it as far as the construction of a small ring fan. Working out the details and building a bigger one are next. If you want to know more email me at ottobelden@yahoo.com or leave a comment!