Introduction: Desktop Fire-Tornado
Use caution when working with fire and flammables!
I recently placed a meat thermometer next to the acrylic cylinder. It's temperature was starting to exceed 190 Degrees F. The acrylic that I was using was regulated for up to 170 I believe. With that being said I would not run this to long unless you have a cylinder material that is more resilient to heat (glass).
In the clip below there are two setups. I will have more details about there differences at the end.
This is an adaptation as a result of a demonstration that I put on for my professor and fellow students in class during Bellarmine University's MAT program. I had seen many fire tornadoes where you spin a lazy suzanne (or that alike) with mesh around the outside. I didn't like the idea of spinning the flammable liquid (alcohol). A quest for a safer method then ensued.
Through much trial and error, lessons learned, and a lot of curiosity; I have built something pretty cool.
I hope you enjoy this build!
Step 1: The Parts
This items list includes a lot of the items that I did use and some items that I wish I had used. Some of these items you might have laying around the house.
Acrylic tube $15
Push button: $0.66
Manufacturer Part Number (digikey) GPTS203211B
Computer Fan $2.99:
Computer Fan Grill Screws: Not sure, these may come with the grill or the fan. My fan was left over from an old tower computer.
Fan grill: $1.66/grill (pack of three)
Metal Can: $0.77
Metal screen home depot $8.65:
9 volt conector/9 volt sleeve: $2.91
DigiKey manufacture number 1290
Cabinet Bumpers: $2.97
Home Depot- Shepards Self-Adhesive Vinyl
Step 2: Make a Stand
This is the stand in which the pineapple can that I cut in half will sit on. I used two paper clip to give the can some support if the device is ever moved. The more centered the can, the more uniform the vortex.
I choose to bend mine slightly in to give more of a pinch to the can.
Step 3: Support for Cylinder
The wire mesh serves as a support for the acrylic cylinder. The mesh is 8 high by 34 wide. The squares in the mesh are 1 cm by 1 cm.
As you can see, I left extra to use as hooks when attaching to the grill and to itself. When I make my next one I plan on having alternating squares at the bottom to attach to the grill.
Step 4: Attach Fan
Using the fan screws, attach the grill to the fan.
Step 5: Fan Stand
The height of the fan above the ground was determined by trial and error. For this fan the height was optimal at three cabinet bumpers high. At the end of the article I will talk more about considerations to make.
Step 6: Wire It Up.
Through my minimal research I found that it is best to have the switch on the positive wire. This is what it looked like before I cleaned it up. Before I started cutting the wire down I wanted to make sure that everything was working properly. It was so I shortened up the wires and hot glued the batty mount and switch to the side.
Step 7: Pour, Light, Flip
I always remove my can from the assembly before adding the alcohol. I don't want to risk spilling inside the fan.
Step 8: Creators Notes
Something that I started looking into was the Cubic Feet per Minute (CFM) that the fans crank out. In the video you see that the one on the right (black) is rising up out of the cylinder. This fan (black) is able to crank out 64 CFM. With it being so powerful I had to decrease the amount of air that it was able to get. Therefore, I lowered the height by one cabinet bumper. In doing so, I was able to stabilize the vortex. I did research on the blue fan and couldn't find any literature on it. The blue one is nice because it is quiet. The black fan is nice because it creates a huge flame. However, the black fan is quiet loud and can be distracting if this is a decoration item sitting off to the side.
After use, the acrylic cylinder gets hot, real hot. I don't know if there is a work around for this or if it's just the nature of having a heat source inside a container. Some thoughts are decreasing the width of the internal container that is holding the alcohol. In doing so, I am guessing that the further the flam is from the walls the better. However, the ratio of width of outer cylinder to inner can my create some issues.
As I continue to make new ones I will update this to let you all know the best design and practices that I come across.