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.

If you want to see one in action, I found this: https://www.youtube.com/watch?v=sApyrDEXGAI

Big Clive took one to bits some years back: https://www.youtube.com/watch?v=uPuvhnIoz2g

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.

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.

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 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.

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/

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.

Using this as a greenhouse vent actuator is pretty cool. It just makes so much sense.

I always wondered what the actuator in the exhaust air valve for my apartment ventilation was - now I'm pretty sure it's a wax motor! You can use a switch to increase the airflow, but it takes a few seconds to react and opens/closes very slowly and quietly.

Huh. Do these work in a vacuum? Presumably if sealed right? I imagine there's a few space applications, particularly with solar panels.

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!)

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

My old espresso machine had one of these, always amazed by the simplicity and robustness. Low-tech solutions often hit different.

Isn't this more like a solenoid than a motor?

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

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.

https://en.wikipedia.org/wiki/Ballcock

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.

Huh, fun coincidence! I just pulled this article as a WikiGacha card recently.

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.

Imagine if you will- a 3d sintered (https://en.wikipedia.org/wiki/Sintering) sand structure. Placed in it is heat collecting material- aka salty-brine- which stores heat as a kind of battery. Placed within it are waxmotors as actuators. Placed within it are nodes with https://en.wikipedia.org/wiki/Silica_gel - the whole thing is literally dumb as a printed rock, but also capable to do work powered by the sun.

It collects moisture from the air, distills the water out of the silica gel and stores it- then releases it in the evening to plants at the root. A terraforming rock, printed in-situ, with materials available in situ (well except silica gel, optical fibers and wax-motors).

...what is the point of starting this post with an egregious slop image?