alt Hacker NewsWax motor
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If you want to see one in action, I found this: https://www.youtube.com/watch?v=sApyrDEXGAI
I'm surprised this page doesn't mention the automotive thermostat which uses the same principle to control the flow of coolant between the engine block and radiator in an ICE vehicle.
Big Clive took one to bits some years back: https://www.youtube.com/watch?v=uPuvhnIoz2g
The expansion of paraffin wax is substantial. I have experience wax potting guitar pickups as well as bicycle chains. I use a skinny, tall tin can for this, placed in boiling water. When the liquid wax solidifies, it not only pulls away from the sides of the can so that the resulting ingot slides out freely, but a void forms in the center. The top surface has a depression and a deep hole in the center.
Using this as a greenhouse vent actuator is pretty cool. It just makes so much sense.
I love alternative types of actuators. Electromagnetic motors are great but they're pretty complex to make, require rare earth metals for best efficiency, and require gearing in most applications. I think in the far future most of our devices will be using other types of actuators, probably made mostly of organic materials. There are many concepts for alternative actuators that just need some breakthrough materials to work.
The greenhouse vents example reminds me a lot of a float valve (or ballcock).
It's a simple mechanism that used buoyancy to either open or close valves as water level changes in a container.
Wax elements are also used in thermostatic valves for faucets (to keep faucet temperature constant given variable hot and cold mains): https://rogerdickey.com/the-ideal-faucet/
Seems this would make it possible to make a relatively cheap waterproof actuator if you made it out of something corrosion resistant?
I've been looking for actuators to use in damp/wet environments and sealed actuators are rather expensive and supposedly don't last too long
I have this in the greenhouse that came with my house. Seeing its roof closed in fall after it had been open all summer made me question my sanity.
Huh. Do these work in a vacuum? Presumably if sealed right? I imagine there's a few space applications, particularly with solar panels.
My old espresso machine had one of these, always amazed by the simplicity and robustness. Low-tech solutions often hit different.
I got one from a microwave, it opened vents. It is incredibly strong, also, takes soo much power and is so slow - although i suppose near heat it must work great.
Objects like this make me think of grimdark (steam|diesel)punk works like the video games Dishonored or BioShock. It feels like there's a touch of occultism or corruption whenever one creates a device that exploits analog side effects to create machines in a closed, black-box package.
My mini truck uses a couple of these with vacuum lines to control the choke and EGR. They are expensive to replace for obvious reasons.
now go blow your mind with the first known conversion of electrical to mechanical energy via "Franklin Bells"
TWO HUNDRED SEVENTY FIVE years ago
in 1752, wow
(but they had no idea why it worked)
* https://en.wikipedia.org/wiki/Franklin_bells
Before the storm, the device would ring to remind Franklin, who had been obsessed with the study of lightning, urging him to chase the lightning
ha "chase the lightning" needs to be a catchphrase
I once had an interview at PA consulting where they asked one of those questions where they have "the answer" but their question isn't well specified enough to lead to that unique answer. They kept adding conditions, but I hadn't ever heard of wax actuators before. (I was like 19 or something - didn't get that job!)
...what is the point of starting this post with an egregious slop image?
Wikipedia page has a small error. It shows an actuator (i.e. wax motor) described as thermostatic radiator valve https://en.wikipedia.org/wiki/Wax_motor#/media/File:Thermisc...
These are two separate things: thermostat will close and open based on surrounding temp., the actuator on the other hand opens and closes based on energizing a heating element that is driven by a separate thermostat.
Wax motors are pretty cool things. They rarely fail and do their job even in damp environments. I take care of my better half's hotel with approx 100 of these installed and we replace one of these once every couple of years.