We’re fascinated by things with no moving parts or active components that work simply by virtue of the shape they contain — think waveguides and resonators for microwave radiation. A similarly mystical device from the pneumatics world is the Hilsch Vortex Tube, and [This Old Tony] decided to explore its mysteries by whipping up a DIY version in his shop.
Invented in the 1930s, vortex tubes are really just hollow tubes with an offset swirl chamber. Incoming compressed air accelerates in the swirl chamber and heads up the periphery of the long end of the tube, gaining energy until it hits a conical nozzle. Some of the outer vortex escapes as hot air, while the rest reflects off the nozzle and heads back down the pipe as a second vortex inside the outer one. The inner vortex loses energy and escapes from the short end as a blast of cold air – down to -50°C in some cases. [Tony]’s build doesn’t quite approach that performance, but he does manage to prove the principle while getting a few good-natured jabs into fellow vloggers [AvE] and [Abom79].
We’ve covered vortex tubes before, but as usual [Tony]’s build shines because he machines everything himself, and because he tries to understand what’s making it work. The FLIR images and the great video quality are a bonus, too.
If you’re going to pass the hat for donations to your hackerspace, you might as well add to the value proposition and give potential donors a little something for their generosity. And what better way to cash in than to channel the inner Brony in your donors with a My Little Pony themed dollar-bill vortex box?
Sick of the boring cheezy-poof jug her hackerspace was using as a donation jar, not-a-Brony [Michelle] was inspired by the CRASH Space mascot Sparkles, pictured left, to build a new box that will maximize donations by providing donors with a multimedia extravaganza. The Plexiglas box, resplendent with laser-cut acrylic hearts and spangled with My Little Pony stickers, is fitted with a sensor so that donations trigger an MP3 of the MLP theme song. A scrolling LED marquee flashes a gracious message of thanks, and to complete the experience, a pair of fans creates a tornado of the fat stacks of cash in the bin.
Putting a little [Twilight Sparkle] into your donation box makes good financial sense, as does providing incentive to deposit bills rather than coins. This project reminds us of our recent post about a custom claw machine which could be leveraged as a value-added donation box – just add a coin slot. And rainbows.
Recreate the look of a tornado by building this water vortex art piece. The components that go into it are all very simple and can be found in your recycling bin with the exception of a motor and a way to drive it. The hard part is going to be getting to the point where you don’t have any leaks.
[Ixisuprflyixi] went with an empty salsa bottle to house the vortex. It’s a pleasant shape for the project since it’s both tall and narrow and it’s got a bit of a sexy curve to it. The base of the machine is a plastic bottle which looks like it might have been for Metamucil, but we’re not sure. The important part is that it needs to be made from HDPE, as a portion of the container will be used to make the impeller. That’s the part that attaches to the motor shaft inside of the container. Give it a spin and you’ve got yourself a tornado in a bottle. See it in action after the jump.
As with its dry-land relative, this technique uses a tiny pager motor. The device is designed to vibrate when the motor spins, thanks to an off-center weight attached to the spindle. [Lee’s] first experiment was to shove the motor in a centrifuge tube and give it an underwater whirl. He could see waves emanating from the motor and travelling outward, but the thing didn’t go anywhere. What he needed were some toothbrush bristles. He started thinking about how those bristles actually work. They allow the device to move in one direction more easily than in another. The aquatic equivalent of this is an angled platform that has more drag in one direction. He grabbed a bendy straw, using the flexible portion to provide the needed surface.
Check out the demo video after the break. He hasn’t got it connected to a vessel, but there is definitely movement.
The Ranque-Hilsch vortex tube is an interesting piece of equipment. It can, without any moving parts or chemicals, separate hot and cold compressed gasses that are passed through it. Interestingly enough, you can cobble one together with very few parts for fairly cheap. [Otto Belden] tossed one together in a weekend back in 2009 just to see if he could do it. His results were fairly good and he shared some video tutorials on its construction.
His latest version, which you can see in the video below, takes compressed air at about 78degrees and spits out about 112degrees on the hot side and 8degrees on the cold side. Not too bad!
[Ben Krasnow’s] water vortex machine has been an exhibit in the lobby of the San Jose City Hall for quite some time now. Unfortuantely he recently had to perform some repair work on it due to the parts inside the water chamber rusting.
This is the same water vortex that we saw about a year ago. It uses a power drill to drive an impeller at the bottom of a water column to produce the vortex. That impeller was made from painted steel and after being submerged for eight months it began rusting, which discolored the water. [Ben’s] repair process, which you can watch after the break, replaces the shaft and the impeller. He reused a plastic PC cooling fan as the new impeller. The replacement shaft is stainless steel, as is all of the mounting hardware that will be in contact with water. But for us, the most interesting part of the repair is his explanation of the shaft gasket and bearings. Two thrust bearings and two radial bearings ensure that the shaft cannot move axially, which would cause a problem with the gasket. He had intended to swap out the oil seal for an all Teflon seal but the machined acrylic wasn’t conducive to the part swap. Instead, he replaced it with the same type of gasket, but bolstered the new one with some silicone to stave off corrosion.