A quick project for the Forth of July.
I saw a video of someone making smoke rings online. The device shot a burning ball of fuel into the air that turned into a vortex of black smoke. Searching the web did not turn up much information on how this worked. I finally found one video that showed one for a science fair project that gave me enough information to figure it out. This video also described the recipe for the fuel a mixture of gasoline, diesel, used motor oil and dish detergent. Basically the fuel needed to be blown into the air from a long vertical pipe and ignited as it exited the tube. The charge of fuel was stored in a U shaped bend at the bottom of the pipe. Compressed air from a tank was used to blow the fuel out of the pipe. My goal was to keep my design as simple as possible. The air tank needed a compressor to fill it and a valve to let the air out. I chose to eliminate all that and use what I call a gas generator to eject the fuel.
The base of the smoke ring generator. The fuel is stored in the U bend. The gas generator is the short length of pipe with the cap on the end. To operate the generator some fuel is poured down the barrel. About one soup can of fuel works well. Then the gas generator is unscrewed and loaded with the proper amount of black powder and a fuse is inserted at the end.
A propane torch at the top is used to ignite the fuel as it exits the pipe.
Above is the initial blast from the generator before it forms a smoke ring.
There is a video on youtube on the generator in action. https://www.youtube.com/watch?v=d2KmAEdk2gk