I am so glad there are Clives in this world, producing fascinating educational videos without the need to hype anything up, just straight to the point with no BS. Thanks, Clive!
Now if I ever come across this technology, or some else asks what it is. I will know. In my endless supply of almost useless, if not used once in my life time, surplus of knowledge.
The copper -nanoparticles- [particles] in the wax are purely to improve the thermal conductivity of it, without it the outside bits of wax would heat up and cool down quickly while the center would be insulated by the rubbish thermal conductivity and high specific heat of the outside wax (paraffin ~0.2W/mK & 2.1 kJ/kg). Interesting patent WO1997049914A1 describes a wax motor very similar to this one however it uses "a copper wire mesh soldered to the housing to distribute heat uniformly and instantly throughout the wax". Special molecular structures of wax are used to increase the expansion of the wax for a given temperature along with the volume of wax. Graphite and aluminum oxide also seem to be common additives but I'm not quite sure why, some sources refer to them as 'fillers', others state they improve the phase change in some way and some state the graphite allows for current to be passed through the wax for on demand actuation. Currently there is a lot of research that uses paraffin wax impregnated with copper nano-particles for direct solar energy storage (and other energy storage / thermal ballast).
Also very similar technology is used in the plastic housing of LED lamps, they use metal nanoparticles including Cu, Al and Ni to make the plastic thermally conductive. It's cheaper than a metal heatsink and you don't have electrical insulation issues.
According to the vid " How Its Made - 357 Automobile Thermostats " on the channel " How its made " , in addition to copper, there is graphite and aluminum ore in the wax. I'm betting these are adjusted to get the wax into a general temp range. Final temperature calibration is done by heating the element and squeezing the can until the plunger is at the correct height.
Thanks for that info snippet! Not sure about the actual nano-size needed here: we can see copper particles on Clive's photo (~40x). Don't see the need for convection flowing of molten wax in this tiny setup, hence no need for nano sized particles? Btw, before the buzz term 'nano', we called it a colloid or 'colloidal suspension', but you're probably aware of this ;) The solar energy application sounds Interesting, I know of paraffins being used as phase change materials due to there 'easy tweaking' to change phase on customised temperature ranges, making the design of latent heat storage nicely compact in residential applications. With the copper suspension 'tweak' industrial applications (due to increased speed of absorbance as well as release of latent heat) seem very possible!
Scooters use one of those to control the choke (enrichment of the gas/air mixture when the engine is cold). Works pretty good because the thermal characteristics of the wax motor model the thermal characteristics of the engine. That way they control the choke based on the engine temperature without the need for a temp sensor and control circuit. Very smart!
Bi-metallic spring actuating the choke butterfly valve is the most common method of automatic choke control. I can see this working as well, however the actuation would be much slower and also smoother..
AvE did a video June 2018 where he similarly did a teardown and cut one open. Great minds think alike! Thanks for sharing your videos, Clive. Always a delight. Also, I love seeing the expertise expressed in your comment section. Glad to see the confirmation from some commenters about the copper helping with heat transmission through the wax
This is made exactly the same as a wax stat in a car’s thermostat in the cooling system. Yes the copper is there for thermal transfer reasons. I also forgot to add the slight dimple crush marks are calibration marks. They change the volume of the wax chamber ever so slightly, altering the characteristics of the opening as the wax consistency isn’t always repeatable.
@@davelowery2992 never ever seen a Thermostatic Valve on a car yes i have seen plenty of thermostats and termocouplers but never a thermostatic valve maybe you can post a picture of one in a car !?
never ever seen a Thermostatic Valve on a car yes i have seen plenty of thermostats and termocouplers but never a thermostatic valve maybe you can post a picture of one in a car !?
@@lacossanostra For a 2 way ( SPDT in electrical switch parlance ) automotive thermostatic valve, have a look at a STANT 13649 . For a single way ( SPST in electrical switch parlance ) automotive thermostatic valve have a look at STANT 45859 .
@@TheJunky228 It may be used in some designs like that, but just some dab of silicone grease is the modern sealant variant. Oh, and saves money not spent on an o-ring in manufacturing.
Yeah, my thought also was, that red disk is a shim to adjust the length if either the amount of wax was not dosed quite right or to adjust the length for the actual application.
Just a guess , I think the copper in the wax is there to transfer heat through the wax so it heats evenly, otherwise the plunger would heat just the base and wouldn't allow the plunger to move till the wax near the plunger melted. Just a guess for me.
According to the vid " How Its Made - 357 Automobile Thermostats " on the channel " How its made " , in addition to copper, there is graphite and aluminum ore in the wax. I'm betting these are adjusted to get the wax into a general temp range. Final temperature calibration is done by heating the element and squeezing the can until the plunger is at the correct height.
@@bobroberts2371 calibration is done by using different strengths of the return springs or lengths. A 180 degree would have a weaker spring than a 190 degree.
New viewer here, I'm studying electrical installation and have recently started a new job in maintenance. This is the best content I've seen in a while on RUclips! Great videos thank you!
I had my first experience with a "wax motor" in a washing machine. I could not even dream of what in the world is a wax motor. Well I replaced it with a new one .Then i took the old one to my work shop to experiment with .What a neat thing.
My experience with a wax "motor" in my Neptune washing machine wasn't as positive. The transistor controlling its heating element burned out so the door wouldn't lock shut, which let it dump clothes out during a spin cycle--fun! Plus, the wax "motor" operated about as quickly as paint dries (when it worked), so forget quickly adding something you left out to the wash load--come back later, maybe. Wax motors just seem to me like a supposedly cheaper replacement for a solenoid, and one that also doesn't work as well as a solenoid.
@@gizmonicman9879 The slow operation is a feature. The door remains latched for about a minute after a power failure, allowing the drum to stop or the heating elements to cool. It is then released without needing to re-apply power. It would be difficult to achieve the same action with a simple electromagnetic or motor-operated latch.
My newer LG drum washer has a solenoid lock, and it works just fine. The slow operation is a bug, IMHO. Wax motors are also, I believe, less reliable than solenoids; they are certainly quieter, but I haven't yet done a cost comparison to a solenoid, so I don't know if they're cheaper. I'm not betting on a higher cycle life for a wax motor versus a solenoid, though.
@@gizmonicman9879 your new lg also must have a brake for the drum or even use brushless motor with a brake feature so if power goes out brake is applied to the drum and then is safe to use a "fast" solenoid, in the older ones that the drum will free spin for a few seconds in a power out situation the wax motor offers a more suitable alternative also believe that the solid copper body special wax+copper compound stainless plunger rubber seal separator shim and the heater could make the wax motor more expansive to produce than a simple small solenoid tha despite using a copper coil uses cheaper materials for the other components
@@gizmonicman9879 Wax motors are considered far more reliable and long-lived than equivalent electromagnetic devices, especially in the damp environment of washing machines and dishwashers.
Well I see the comments did a good job at finding out why the metal powder is in the wax. My initial guess was that the metal particles are there for calibration. Use the same prefabricated parts and get less movement by increasing the metal content in the wax mixture. ( because the metal thermal expansion is way less than the wax).
I mean you can take everything appart if you know what to expect and what precotions to take the do not take apart only is there soo that nobody sues them and so that it stays reliable.
No need to write it. If it's not too expensive, or too hard to get, or borrowed, it kinda have to go apart. Epecially if there is a good chance of getting it back together.
EVERYTHING can be taken apart... Not everything can be put back together in a functional state... When Clive takes it apart, MOST things can't be put back together in a functional state...
Wax motors are awesome. They were used on diesel injection pumps for cold starting once upon a time. Also saw it on an old 70s articulated front loader I repaired once. It had mechanically operated shutters in front of the radiator that would open as the wax got warmed up. Very cool to see in action.
I doubt that is has a huge effect as the copper and brass outer case are joined together and will transfer a lot of heat. If the metal plunger was in direct contact with the membrane you would have relative shape edges in contact with the membrane and it could damage it. The rubber plunger will deform so not point with the same high pressure. So my suspicion is that is is to increase the life of the membrane.
wax is uncompressible, when heated it will expand and if no damper exists to absorb the displacement when the plunger is at its down position, it could tear off the body
I think it might be to protect the membrane from the sharp edge of the plunger. Having a little compressible rubber spacer would allow some of the force to be distributed a bit better.
The rubber plug takes up possible excessive force the wax motor may produce until fully extended when whatever is operated by it may already have reached end of travel. This prevents the wax from producing excessive force on the crimped seam of the housing.
Diaphragms allow a small amount of movement, while providing an inexpensive, absolute seal. I've taken apart an oil pressure switch from an automobile. It had what looked like Kapton (polyamide) for its diaphragm. Nice educational video, thanks. Thoughtful comments too. Copper powder for conducting heat makes sense. Dremel with a cut-off wheel, one of my favorites. This is what the Internet SHOULD be used for!
I've become so accustomed to Zoom meetings over the last 6 months I caught myself audibly replying "Yes" to your question about whether we could see the copper shimmering. I like the idea of these to allow for fiddling toddlers, but realised that the fused spurs would just be rapidly turned on and off instead of moving the TRV's! :)
I am a Maintenance Set-up Technician for a company called Vernet US. I assemble and test these for a living. I setup tooling and test for production, before the line runs. Great video.
Thank you! An interesting subject, presented calmly, without hyperbole, and the work you put in to demonstrate. Also, last but not least, the intelligent/educated speculation about what your vast knowledge doesn't cover, that you do not pretend to be absolute truths. RUclips need more like this and more youtubers like you. I'm *not* criticizing your more dramatic videos, or video names, those videos are really good to, and without them I might not have found your channel, because they're needed to grow the channel.
This same sort of wax motor powers the thermostat in your car's cooling system. Spring close, wax motor to open as temps in cooling system rise. They even have failsafe thermostats, which employ a dual wax motor mechanism. The secondary or emergency wax motor operates once only during an overheating situation, and by use of a ratchet clip the thermostat is then permanently locked in the open position. If you have one of these and your car overheats, you must replace it or your car will run forever cold after that.
What vehicles are these in? I've replaced over 1k thermostats. The fail-safes use a hole in the stopper plate with a floating pintle that just falls open when flow is impeded by lack of wax motor action.
@@dachine86 You misunderstand the pintle action. It is there (as an air bypass) to ensure that an air pocket does not form around the stat capsule and cause the stat to not function as desired by not detecting the true water temp.
I remember my dad showing me one of these on the stove with boiling water. I had no idea what witchcraft was inside. I'm pretty sure it was inside an engine coolant thermostat of an old truck. Great, simple devices, no need for electricity or sensors.
Hi, great channel I discovered when trying to troubleshoot polypipe underfloor heating setup. i think it is important to mention that these actuators are either normally close or normally open when no 240v AC is present. So in my system, without power plunger is sticking out slightly and it retracts when you apply voltage to terminals, thus opening the valves on manifolds. Your actuator seems to be normally open, because heating of wax pushes plunger out. Obviously that depends as well on valve design itself.
The copper might be added to tune the amount of expansion. I imagine it will expand less than the wax, while still transferring heat well, so they can add more copper to reduce expansion and get it to the amount they need.
@@bigclivedotcom According to the vid " How Its Made - 357 Automobile Thermostats " on the channel " How its made " , in addition to copper, there is graphite and aluminum ore in the wax. I'm betting these are adjusted to get the wax into a general temp range. Final temperature calibration is done by heating the element and squeezing the can until the plunger is at the correct height.
That's what I about to say, this is my vote. for instance check the concept of stress concentration in a flexible thing with a certain volume of filler particle included. This comes from years ago remembering how polymer gets reinforced by adding inert (but well bonded) filler particles. I think this is the same but in fluid, not solid, state.
Exactly the same principle as a wax stat or thermostat in virtually every car on the road , they were also used in some carburettors (pre fuel injection) as a means of raising the idle speed ( pierburg used them on the 2e2 and 2e3 carbs it was simple called a wax stat) Great video as always Clive , take care and stay safe
I think the fact that there's copper in the wax would likely mean that it's used to distribute/spread the heat quickly throughout the wax, so as to not have the wax nearest the heating element at a significantly higher temperature than the rest. That heat energy will spread evenly much in the same way that it does in a copper-bottomed stove pot/skillet. And pretty much for the same reason -- even heat spread. Otherwise, why use copper? They'd most likely use steel or some cheaper metal before they'd use copper, unless they're specifically trying to make use of copper's phenomenal thermal conductivity. Copper is damn near as thermally conductive as silver, and copper is far less costly than silver. In the world of computing, the best CPU coolers have a copper plate on them where they make contact with the CPU lid -- to move that heat quickly away from the CPU. And the best of the best, when it comes to thermal grease placed between the cooler and the CPU, contains real silver particles.
The force applied when the wax melts is the inverse of the force applied when water freezes since water is one of the odd materials that expands and gets less dense when frozen. Turns out most things that melt and freeze expand when melted and contract when freezing.
Huh. You know, I've never actually thought too hard about the fact that the water-ice thing makes no apparent sense based on everything else I know about thermal expansion/contraction... That is weird indeed. Gonna have to go and find out why that might be, cheers!
@@loek3336 I meant keeping the wax from leaking out over time as it would escape past the moving parts. They don't use O-rings or other conventional seals, nor is the wax contained in a metal bellows. They use a rubber diaphragm/inter-poser it appears from Clive's cutaway. Between the crimps. Now we know.
Impressive use of a fundamental physical characteristic of a material. Kind of the reverse of water expanding as it freezes. If you really want to break something, fill it with water, seal it tightly and then freeze it.
on the show "how it's made", they showed the production of car thermostats. they have a nearly identical wax motor inside, and showed the production of same. you can see them mix up the wax and copper powder stuff they put inside. to calibrate the temperature, they squash the sides. you can see the marks on that one in the video.
I found the following in a research paper. It should apply if the wax being used is pure paraffin. But since it has copper in it, the 15% could be different. But 75◦C should still apply. "Paraffin is a phase-change material that exhibits approximately 15% volumetric change at relatively low temperature (75◦C)."
Plenty of other people have confirmed the copper is mixed in with the wax for thermal conductivity. It would also add some extra latent heat capacity which would mean it takes longer for the valve to close after the power is removed. The pin is best made out of stainless steel, because if made of a non-stainless steel it would only take a bit of moisture getting to it to cause enough rust to completely seize it up. Making the pin out of brass would solve the corrosion issue, but running a soft metal against a soft metal in sliding friction like that is a bad combination and it would be likely to seize or wear much quicker than copper on steel.
Interesting. Thanks for that. I occasionally still pull something to bits to see how it works, but you have taken it to a whole new level for us in this and your other videos. Keep them coming.
Great teardown - as ever. I can’t see how this ‘regulates’ water flow - as a common thermostatic radiator valve would. It seems to be designed to be full on or full off. You mentioned it’s used as a door-lock actuator. Well, that works, as you want the door locked or unlocked. You don’t want an ‘In between’ state. But if I want to control the amount of heat from my radiator, I want to regulate the water flow into it. Wi-fi radiator valves do this. (As, of course, do old-school thermostatic valves.) For the wireless valves, the system controller can work the thermal sums out and set the radiator valve position accordingly. With this wax motor valve, the radiator will be full on or full off, which makes it harder to maintain a constant environment in a room. I suspect the power requirement will be higher than a wi-fi valve, too. Once the wi-fi valves have moved onto position, they can turn off. In fact, they are commonly battery powered. (This will be a pig, once battery-life end arrives.) HOPI shows 22 or so Watts to get the heater going, and around 2W on-temperature. If we’re turning the wax motor on and off to turn the radiator on and off to try and keep the room at temperature; there’s lots of on/off 22W heater cycles - not 2W ones. It will be doing many more cycles than a proportional valve. Also, it’s a mains thingy - so I need new, and possibly unique, wires to each of my radiator valves. That - as an after-house-build fit, will cost far more than the valves ! Where am I coming from ? I want a system in the house which lets me control each room’s temperature. Presently looking at some sort of clever central hub, which lets me say ‘the kids are home for holidays’, which enables their thermostats and heats their rooms accordingly, but within max-min temperature range. ‘We’re going on holiday for a week’ ‘daughter is away for 3 days’ - those sorts of real-world controls. Each room needs a wi-fi stat, and wi-fi valves on the rads. The hub needs ‘macros’ - a script of commands it executes. Then I’m there, I think. Honeywell have something, but I’ve not researched hard, yet. Any-road-up, a great video and now I know how these chaps work. Most interesting. Thanks lots for that. Matt
I had a 90hp yamaha outboard motor with a wax motor. it was used to control the choke on start up. It wasn't so much a choke as in butterfly valves to restrict air flow through the carbs but instead the wax motor allowed a direct feed of extra fuel into the cylinder 1 carb, once running it would apply power and the wax motor would shut this supply off in about 30 sec. A very interesting design in the way it made it very easy to start and it was hard to flood with engine compared to a standard choke
Thanks for doing this video. Wax motors are also found in dish washers, in operating the detergent cup and rinse agent and some refrigerator ice chute flappers.
This would be what is used for the Thermostat in the car for the coolant valve. I believe the early ones were Bi-Metal but the Wax Motor turned out to be cheaper and was more reliable. They are also much easier to calibrate for a specific temperature range. As the engine coolant gets hot it opens the valve slowly and maintains the the proper engine temp. It is the rubber seal that winds up deteriorating that causes that thermostat to go bad.
I think the copper powder's function is to ensure the entire mass of wax maintains a stable temperature throughout its mass. That way it all goes liquid at once, with no hard spots to impede the operation of the actuator plunger. Cheers!
This man (Big Clive) is simply Fantastic! What a virtual classroom full of "hands on" knowledge one can gain from simply subscribing to, and then, subsequently, paying attention to, all of the very interesting and highly useful information that so freely flows from Mr. Clive's mind to the viewer's ears. I must respond instep with this posting with a written --> Big Thank You Big Clive
Very curious indeed! I entered knowing nothing of wax motors.. I am familiar with thermo wax being used inside Honda GCV lawnmower engines for the auto-choke system (and the fun when it leaks out and machine wont start[and/or the choke actuator arm is siezed]).. Wonderfully clever invention
I have a wax "motor" that doesn't need electricity to drive it, (so technically it's not a motor!). It opens and closes the windows on my greenhouse, but works in the same way, the sun heats the wax in the cylinder which expands and pushes a ram to open the window, and closes as it cools :)
It's still a motor in the same way that a diesel engine is also a motor. It just isn't electrical. Motor 1: one that imparts motion specifically : PRIME MOVER 2: any of various power units that develop energy or impart motion: such as a: a small compact engine b: INTERNAL COMBUSTION ENGINE especially : a gasoline engine c: a rotating machine that transforms electrical energy into mechanical energy from www.merriam-webster.com/dictionary/motor
This is when you call up This Old Tony to make a new casing. He will realize you are kind of dim for asking a machinist to replicate a stamped part, but he will likely be nice enough about the request since he can't resist the chance to squeeze puns out of a wax motor rebuild.
The main failure mode is the cracking of the rubber separator. The wax can achieve 30,000 psi on expansion, and the copper is to conduct heat and it's very compatible with brass and soft so it won't damage the rubber separator. We use them in radiant floor heating systems. The biggest problem with them is the time it takes to test because of all the delays. On an average house we have a full day or two for testing and adjusting for two guys, so as you can guess it's quite expensive compared to typical zone valves.
Copper does expand more than other metals with temperature changes. But copper is also more thermally conductive. The house my grandmother moved into when it was new in the late 1960's had copper plumbing with both the water and the waste pipes. The waste pipes would expand and make noise through the wooden wall frames in the basement when she drained the kitchen sink of the warm dish water. I use the wax piston openers to automatically open the vent on my knock-down greenhouse for seedlings when it reaches above 68° F (20° C). I store these pistons in the refrigerator when not in use as the temperature in my house varies greatly during the year. No A/C here.
We kept running into gas sealing issues because screws holding down a plate kept losing their seal every thermal cycle. My solution was to dump wax in the blind hole, then let it expand into the space under the screw head when it thermally cycled. Sealed it right up, but required extra tooling so we ended up burying it under adhesive instead.
The copper in the wax is a combination of heat transfer and helping prevent the wax seeping around the seals as the wax is very liquid when melted. I am thinking the groove in the plunger may be a seal of some kind, but designed to use the air in the groove for sealing/resistance.
Honda uses one of these to activate the fast idle (cold start) circuit on their early fuel injected bikes. Always wondered what they looked like inside
Wax motors are used in aerospace to unlock furled antennas, solar panels, etc., on satellites. Power is applied in sequence to the wax motors and, various arrangements of springs cause the antennas and solar panels to unfurl and lock into position.
About the copper in the wax, it's a solid state throttle. The copper would be used for the same principle of starting an engine cold or hot, based on the conditions of the wax, and the copper being a conductor, closer or further apart as the wax is heated, increasing the resistance of the wax's conductivity; it's a thermally conditional power regulator, when it's cold, it conducts the best, when it's hot, it has the highest resistance and conducts the worst.
I'd say the diaphragm improves the force the motor can create. When the wax pushes on the wider area of the diaphragm, it has more total force (force = pressure X area). The force is then transferred to the rubber plug and piston. And the expansion is mostly during the phase-change, from solid to liquid. That's why they have a very narrow operating temperature. Once it starts melting, the temperature doesn't rise much for it to completely liquify and open.
I nearly scrapped a $1000 front loading washing machine that would not spin. Turned out that the wax motor in the door locking mechanism had failed. Fixed it for $20!
Mid 80's to mid 90's GM trucks used a wax motor to engage the front differential, not a good idea as it is slow. Later then went to a vacuum operated actuator.
@@bobroberts2371 Mitsubishi used a wax motor automatic choke on carburated cars in the late 80's. They worked well, but had a relatively short life. To make matters worse, back then you had to buy the whole damn carb to get a new wax operated choke. Just one more thing that put the stake through the carburator's heart.
@@tomhoehler3284 Chrysler used Mits engine ( 2.6 ) in the K car and smaller versions in the ( Mits ) Colt . The Mikuni carb usually had a bad choke pull off diaphragm that was easily changeable. The decell dash pot orifice usually needed cleaned to prevent a vacuum leak at idle. Never had a bad choke stat though, worked on dozens of these over the years. ( And the Ford VV too )
copper powder is in there to help get the heat into the wax and to increase its heat capacity so that the volume of the mixture changes slower than it would if it were just pure wax. it doesn't have anything to do with the sealing - the wax would wick out those edges if at all possible (regardless of whether it had to separate from the copper powder first). given the visible travel of the stainless plunger we saw in the last video, i wonder if the flexible seal protrudes into the extension shaft when the wax expands and pushes the flexible puck/spacer into the shaft further than just roughly flush with the shaft orifice into the wax chamber. certainly, the puck/spacer can't be drawn so far into the wax chamber that it gets misaligned with the shaft. the red spacer seems to be both a way to set the min/max position of the stainless plunger and perhaps a way to protect the puck/spacer from the base of the plunger. aside from those, i don't know why it would be there. if the flex seal protrudes into the extension shaft, i wonder if that wearing out is one other failure mode. there really can't be that many failure modes to something so simple. the wax could leak, i guess, but everything is at such a high pressure in there that i have to imagine that they get that chamber crimp correct 'forever' or it immediately fails before they ship the part. the heater disk at the end failing or cracking away from the brass chamber i would think is the 99% failure mode. i find it weird that the stainless plunger has that o-ring groove looking feature. it seems unnecessary for this kind of motor. maybe it's used in another motor with the flex seal and direct contact between the wax and the plunger. or, maybe they use the groove to jig it when they assemble the part. that would be fun to know.
There are wax motors in many cars trottle bodies to control the air flow when the engine is cold. Very simple but effective component. Nice video, as always! =)
i have a 230V wax motor somewhere in my piles of electric stuff, it was from a room ventilator that had it's blinds slowly opening when turned on, an old "Vortice" model
Just like a car thermostat! Always wondered what exactly was inside. Thanks! The copper in the wax is interesting. Maybe it is like a built in "stop leak" type of thing.
Looks exactly like a Vernatherm (the core of a thermostat used on engines) Johnson/Evinrude outborad motors use them to control cooling water flow. Interesting to see whats inside.
These operation of these wax motors and car thermostats depends on a solid state phase change (not melting) in the wax as the crystal structure changes with temperature. The wax molecules are idealised as straight n-chain polyolefins, where n is 20+. Above a critical temperature the molecules vibrate and rotate about their length, presenting a cylindrical aspect and the crystal structure is hexagonal, consisting of stacked cylinders. As it cools the wax molecules stop rotating and adopt a flat zig-zag conformation and the crystal structure changes to monoclinic with about a 15% change in volume. There is another smaller volume change on melting. The range of temperature over which the phase change happens can be tuned by adding side chains to the wax molecules and varying their lengths.
I read that the Lunar Rovers and such use wax motors as mission critical parts because they have proven their reliability over the decades in space flight.
My best guess is that the copper is for heat transfer and probably on some level it would be considered 'filler' so that the effect of the wax expanding/contracting would be amplified by the particles just being solid/incompressible.
Clive and Elves a question with TRV's the oil filled motors (Drayton, Danfoss) are quicker and more accurate at keeping a room at a specific temperature the wax filled ones are cheaper and have a larger temperature spread in turning on and off. Are the electric actuators wax and oil wax for the cheaper ones and oil for the more expensive or is this drivel for they are all wax.
Pretty sure they are all wax, since it's the phase change from solid to liquid (and vice-versa) that produces the density/volume change required to make the thing work. The cheaper ones probably have less of the comparatively expensive metal particles embedded in the wax though, hence their actuation cycles take longer due to reduced thermal conductivity of the wax (also making them less electrically efficient).
If I’m not mistaken fire sprinklers use a simile wax motor. They are colored differently for different temperatures. But when there is fire it heats up the wax and it expands opening the valve for water to put out the fire
Robert Szasz thanks for the correction. Similar mechanism (thermal expansion with a gaseous state change?) different medium 👍👍 I guess I really WAS mistaken :-)
I used these to move some shutters inside solar panels that got too hot..they were categorized as pcm (phase change material) linear actuator I do believe
The rubbery plastic plug is probably to protect the rubber disc when the wax expands, so it isn't pressing against anything hard which could perforate the disc.
Just had an epiphany while reading the comments. How about the copper particles in the wax expand too, and exactly compensate for the slight expansion of the outer case! So keeping the volume INSIDE the case the same at all temperatures. Then the wax expansion sums just work with a constant volume. I am unanimous both that this is brilliant, AND that I am the most modest person commenting here. Many people can’t see this ...
IU was wondering if the copper in the wax could be for electrical conductivity as well as thermal. The other thought that went through my mind is with regard to coefficient of expansion. IE the copper used to "tune" the wax expansion coefficient.
Why are there so many different colors of wax? Are they different materials or is that just the structure of the impregnated copper leading to structural color due to crystallization or something?
I am so glad there are Clives in this world, producing fascinating educational videos without the need to hype anything up, just straight to the point with no BS.
Thanks, Clive!
We are unique!
Plus we anticipate sparks, fire, and explosions. We are rarely disappointed. 😏
And when he does hype something (carbonated adult beverages!) it is fun...
From never having heard about wax motors to knowing all I need to know in 7 minutes 👍
Now if I ever come across this technology, or some else asks what it is. I will know. In my endless supply of almost useless, if not used once in my life time, surplus of knowledge.
All in all, knowledge is a light burden to carry 🦊
Mechanical thermostats in you car is a wax motor.
Motorless zone valves for hot water home heating systems.
The copper -nanoparticles- [particles] in the wax are purely to improve the thermal conductivity of it, without it the outside bits of wax would heat up and cool down quickly while the center would be insulated by the rubbish thermal conductivity and high specific heat of the outside wax (paraffin ~0.2W/mK & 2.1 kJ/kg).
Interesting patent WO1997049914A1 describes a wax motor very similar to this one however it uses "a copper wire mesh soldered to the housing to distribute heat uniformly and instantly throughout the wax".
Special molecular structures of wax are used to increase the expansion of the wax for a given temperature along with the volume of wax. Graphite and aluminum oxide also seem to be common additives but I'm not quite sure why, some sources refer to them as 'fillers', others state they improve the phase change in some way and some state the graphite allows for current to be passed through the wax for on demand actuation.
Currently there is a lot of research that uses paraffin wax impregnated with copper nano-particles for direct solar energy storage (and other energy storage / thermal ballast).
Also very similar technology is used in the plastic housing of LED lamps, they use metal nanoparticles including Cu, Al and Ni to make the plastic thermally conductive. It's cheaper than a metal heatsink and you don't have electrical insulation issues.
That is why they call you the wizard.
According to the vid " How Its Made - 357 Automobile Thermostats " on the channel " How its made " , in addition to copper, there is graphite and aluminum ore in the wax. I'm betting these are adjusted to get the wax into a general temp range. Final temperature calibration is done by heating the element and squeezing the can until the plunger is at the correct height.
Was thinking the same thing
Thanks for that info snippet!
Not sure about the actual nano-size needed here: we can see copper particles on Clive's photo (~40x). Don't see the need for convection flowing of molten wax in this tiny setup, hence no need for nano sized particles? Btw, before the buzz term 'nano', we called it a colloid or 'colloidal suspension', but you're probably aware of this ;)
The solar energy application sounds Interesting, I know of paraffins being used as phase change materials due to there 'easy tweaking' to change phase on customised temperature ranges, making the design of latent heat storage nicely compact in residential applications. With the copper suspension 'tweak' industrial applications (due to increased speed of absorbance as well as release of latent heat) seem very possible!
Scooters use one of those to control the choke (enrichment of the gas/air mixture when the engine is cold). Works pretty good because the thermal characteristics of the wax motor model the thermal characteristics of the engine. That way they control the choke based on the engine temperature without the need for a temp sensor and control circuit. Very smart!
I saw about a hundred "car thermostat!" comments on the previous video, but this is a new one. Clever solution indeed, thanks for commenting about it.
no those a bi metals valves not a wax thermostatic valve
@@lacossanostra
Both designs are used in different brands. The wax pellet choke is common in scooters.
VW used a heated bimetallic coil on carbs if you left the ignition on without starting the choke would have fully opened already
Bi-metallic spring actuating the choke butterfly valve is the most common method of automatic choke control. I can see this working as well, however the actuation would be much slower and also smoother..
AvE did a video June 2018 where he similarly did a teardown and cut one open. Great minds think alike! Thanks for sharing your videos, Clive. Always a delight.
Also, I love seeing the expertise expressed in your comment section. Glad to see the confirmation from some commenters about the copper helping with heat transmission through the wax
re: " I love seeing the expertise expressed in your comment section."
Aye. I like the expertise in comments too.
This is made exactly the same as a wax stat in a car’s thermostat in the cooling system. Yes the copper is there for thermal transfer reasons. I also forgot to add the slight dimple crush marks are calibration marks. They change the volume of the wax chamber ever so slightly, altering the characteristics of the opening as the wax consistency isn’t always repeatable.
Looks close to the same as well
i said the same on the last video :) we all have one in our cars. even electric cars have a coolant system.
@@davelowery2992 never ever seen a Thermostatic Valve on a car yes i have seen plenty of thermostats and termocouplers but never a thermostatic valve
maybe you can post a picture of one in a car !?
never ever seen a Thermostatic Valve on a car yes i have seen plenty of thermostats and termocouplers but never a thermostatic valve
maybe you can post a picture of one in a car !?
@@lacossanostra For a 2 way ( SPDT in electrical switch parlance ) automotive thermostatic valve, have a look at a STANT 13649 . For a single way ( SPST in electrical switch parlance ) automotive thermostatic valve have a look at STANT 45859 .
The red disk is to fine tune the spacing between wax and ram pin. The groove on the pin is to hold some grease for lubrication. Hope that helps!
ah, I thought that groove might have been for an unpopulated o-ring, like they designed it then decided they didn't need the o-ring or something
@@TheJunky228 It may be used in some designs like that, but just some dab of silicone grease is the modern sealant variant. Oh, and saves money not spent on an o-ring in manufacturing.
Yeah, my thought also was, that red disk is a shim to adjust the length if either the amount of wax was not dosed quite right or to adjust the length for the actual application.
Interesting how using bulk properties are more reliable and ingenious design. Material science is cool.
Just a guess , I think the copper in the wax is there to transfer heat through the wax so it heats evenly, otherwise the plunger would heat just the base and wouldn't allow the plunger to move till the wax near the plunger melted. Just a guess for me.
Precisely, the reason being that the heat conductivity of wax alone is very low.
According to the vid " How Its Made - 357 Automobile Thermostats " on the channel " How its made " , in addition to copper, there is graphite and aluminum ore in the wax. I'm betting these are adjusted to get the wax into a general temp range. Final temperature calibration is done by heating the element and squeezing the can until the plunger is at the correct height.
That was exactly my thought
@@bobroberts2371 calibration is done by using different strengths of the return springs or lengths. A 180 degree would have a weaker spring than a 190 degree.
New viewer here, I'm studying electrical installation and have recently started a new job in maintenance. This is the best content I've seen in a while on RUclips! Great videos thank you!
I had my first experience with a "wax motor" in a washing machine. I could not even dream of what in the world is a wax motor.
Well I replaced it with a new one .Then i took the old one to my work shop to experiment with .What a neat thing.
My experience with a wax "motor" in my Neptune washing machine wasn't as positive. The transistor controlling its heating element burned out so the door wouldn't lock shut, which let it dump clothes out during a spin cycle--fun! Plus, the wax "motor" operated about as quickly as paint dries (when it worked), so forget quickly adding something you left out to the wash load--come back later, maybe. Wax motors just seem to me like a supposedly cheaper replacement for a solenoid, and one that also doesn't work as well as a solenoid.
@@gizmonicman9879 The slow operation is a feature. The door remains latched for about a minute after a power failure, allowing the drum to stop or the heating elements to cool. It is then released without needing to re-apply power.
It would be difficult to achieve the same action with a simple electromagnetic or motor-operated latch.
My newer LG drum washer has a solenoid lock, and it works just fine. The slow operation is a bug, IMHO. Wax motors are also, I believe, less reliable than solenoids; they are certainly quieter, but I haven't yet done a cost comparison to a solenoid, so I don't know if they're cheaper. I'm not betting on a higher cycle life for a wax motor versus a solenoid, though.
@@gizmonicman9879 your new lg also must have a brake for the drum or even use brushless motor with a brake feature so if power goes out brake is applied to the drum and then is safe to use a "fast" solenoid, in the older ones that the drum will free spin for a few seconds in a power out situation the wax motor offers a more suitable alternative also believe that the solid copper body special wax+copper compound stainless plunger rubber seal separator shim and the heater could make the wax motor more expansive to produce than a simple small solenoid tha despite using a copper coil uses cheaper materials for the other components
@@gizmonicman9879 Wax motors are considered far more reliable and long-lived than equivalent electromagnetic devices, especially in the damp environment of washing machines and dishwashers.
Well I see the comments did a good job at finding out why the metal powder is in the wax.
My initial guess was that the metal particles are there for calibration. Use the same prefabricated parts and get less movement by increasing the metal content in the wax mixture. ( because the metal thermal expansion is way less than the wax).
What it says:
DO NOT TAKE APART
How engineers read it:
MUST TAKE APART IMMEDIATELY
I mean you can take everything appart if you know what to expect and what precotions to take
the do not take apart only is there soo that nobody sues them and so that it stays reliable.
No need to write it.
If it's not too expensive, or too hard to get, or borrowed, it kinda have to go apart.
Epecially if there is a good chance of getting it back together.
"Disassemble Completely"
DO NOT OPEN
=
CUT IT INTO BITS
EVERYTHING can be taken apart...
Not everything can be put back together in a functional state...
When Clive takes it apart, MOST things can't be put back together in a functional state...
Wax motors are awesome. They were used on diesel injection pumps for cold starting once upon a time. Also saw it on an old 70s articulated front loader I repaired once. It had mechanically operated shutters in front of the radiator that would open as the wax got warmed up. Very cool to see in action.
I guess the rubber plunger also acts as a thermal insulator, to prevent heat from flowing through the metal plunger into the wax and vice versa.
I doubt that is has a huge effect as the copper and brass outer case are joined together and will transfer a lot of heat.
If the metal plunger was in direct contact with the membrane you would have relative shape edges in contact with the membrane and it could damage it. The rubber plunger will deform so not point with the same high pressure. So my suspicion is that is is to increase the life of the membrane.
wax is uncompressible, when heated it will expand and if no damper exists to absorb the displacement when the plunger is at its down position, it could tear off the body
I think it might be to protect the membrane from the sharp edge of the plunger. Having a little compressible rubber spacer would allow some of the force to be distributed a bit better.
The rubber plug takes up possible excessive force the wax motor may produce until fully extended when whatever is operated by it may already have reached end of travel.
This prevents the wax from producing excessive force on the crimped seam of the housing.
"Don't turn it on, chop it into little bits." - Old Scots EEVBlog wisdom.
LOL, he already turned it on and demonstrate its operation in the previous video.
Diaphragms allow a small amount of movement, while providing an inexpensive, absolute seal. I've taken apart an oil pressure switch from an automobile. It had what looked like Kapton (polyamide) for its diaphragm.
Nice educational video, thanks. Thoughtful comments too. Copper powder for conducting heat makes sense.
Dremel with a cut-off wheel, one of my favorites.
This is what the Internet SHOULD be used for!
I've become so accustomed to Zoom meetings over the last 6 months I caught myself audibly replying "Yes" to your question about whether we could see the copper shimmering. I like the idea of these to allow for fiddling toddlers, but realised that the fused spurs would just be rapidly turned on and off instead of moving the TRV's! :)
I am a Maintenance Set-up Technician for a company called Vernet US. I assemble and test these for a living. I setup tooling and test for production, before the line runs.
Great video.
Thank you! An interesting subject, presented calmly, without hyperbole, and the work you put in to demonstrate. Also, last but not least, the intelligent/educated speculation about what your vast knowledge doesn't cover, that you do not pretend to be absolute truths. RUclips need more like this and more youtubers like you.
I'm *not* criticizing your more dramatic videos, or video names, those videos are really good to, and without them I might not have found your channel, because they're needed to grow the channel.
Impressed to se you actually put things back together after playing with them. A skill I never had as a child.
I don't think he could put that one back together lol
This same sort of wax motor powers the thermostat in your car's cooling system. Spring close, wax motor to open as temps in cooling system rise. They even have failsafe thermostats, which employ a dual wax motor mechanism. The secondary or emergency wax motor operates once only during an overheating situation, and by use of a ratchet clip the thermostat is then permanently locked in the open position. If you have one of these and your car overheats, you must replace it or your car will run forever cold after that.
What vehicles are these in? I've replaced over 1k thermostats. The fail-safes use a hole in the stopper plate with a floating pintle that just falls open when flow is impeded by lack of wax motor action.
@@dachine86 You misunderstand the pintle action. It is there (as an air bypass) to ensure that an air pocket does not form around the stat capsule and cause the stat to not function as desired by not detecting the true water temp.
I remember my dad showing me one of these on the stove with boiling water. I had no idea what witchcraft was inside. I'm pretty sure it was inside an engine coolant thermostat of an old truck. Great, simple devices, no need for electricity or sensors.
Hi, great channel I discovered when trying to troubleshoot polypipe underfloor heating setup.
i think it is important to mention that these actuators are either normally close or normally open when no 240v AC is present.
So in my system, without power plunger is sticking out slightly and it retracts when you apply voltage to terminals, thus opening the valves on manifolds.
Your actuator seems to be normally open, because heating of wax pushes plunger out.
Obviously that depends as well on valve design itself.
The copper might be added to tune the amount of expansion. I imagine it will expand less than the wax, while still transferring heat well, so they can add more copper to reduce expansion and get it to the amount they need.
It seems to have two functions. A volume adjuster and for transfer of heat throughout the wax.
@@bigclivedotcom According to the vid " How Its Made - 357 Automobile Thermostats " on the channel " How its made " , in addition to copper, there is graphite and aluminum ore in the wax. I'm betting these are adjusted to get the wax into a general temp range. Final temperature calibration is done by heating the element and squeezing the can until the plunger is at the correct height.
That's what I about to say, this is my vote. for instance check the concept of stress concentration in a flexible thing with a certain volume of filler particle included. This comes from years ago remembering how polymer gets reinforced by adding inert (but well bonded) filler particles. I think this is the same but in fluid, not solid, state.
Exactly the same principle as a wax stat or thermostat in virtually every car on the road , they were also used in some carburettors (pre fuel injection) as a means of raising the idle speed ( pierburg used them on the 2e2 and 2e3 carbs it was simple called a wax stat)
Great video as always Clive , take care and stay safe
I think the fact that there's copper in the wax would likely mean that it's used to distribute/spread the heat quickly throughout the wax, so as to not have the wax nearest the heating element at a significantly higher temperature than the rest. That heat energy will spread evenly much in the same way that it does in a copper-bottomed stove pot/skillet. And pretty much for the same reason -- even heat spread. Otherwise, why use copper? They'd most likely use steel or some cheaper metal before they'd use copper, unless they're specifically trying to make use of copper's phenomenal thermal conductivity. Copper is damn near as thermally conductive as silver, and copper is far less costly than silver. In the world of computing, the best CPU coolers have a copper plate on them where they make contact with the CPU lid -- to move that heat quickly away from the CPU. And the best of the best, when it comes to thermal grease placed between the cooler and the CPU, contains real silver particles.
It's apparently used as a non expanding element to tune the maximum amount of expansion.
The force applied when the wax melts is the inverse of the force applied when water freezes since water is one of the odd materials that expands and gets less dense when frozen. Turns out most things that melt and freeze expand when melted and contract when freezing.
Huh. You know, I've never actually thought too hard about the fact that the water-ice thing makes no apparent sense based on everything else I know about thermal expansion/contraction... That is weird indeed. Gonna have to go and find out why that might be, cheers!
Water certainly is suspicious in the vicinity of 0 C. And don't get me started about it being transparent.
Always wondered how they sealed the wax in.
I think they put the wax in, place the seal in and crimp it
@@loek3336 I meant keeping the wax from leaking out over time as it would escape past the moving parts. They don't use O-rings or other conventional seals, nor is the wax contained in a metal bellows.
They use a rubber diaphragm/inter-poser it appears from Clive's cutaway. Between the crimps. Now we know.
How about a wax motor from a shower thermostat?
Your mother who neglected you owes a million dollars tax
And your father's still perfecting ways of making sealing wax
Id buy that for a dollar.
I've wondered how these work for decades. thanks. Surprisingly simple, yet effective and reliable
That’s a really good cross-cut!
Impressive use of a fundamental physical characteristic of a material. Kind of the reverse of water expanding as it freezes. If you really want to break something, fill it with water, seal it tightly and then freeze it.
We used very similar wax motors in the space world that were included with fine silver instead of copper.
They are great little devices.
on the show "how it's made", they showed the production of car thermostats. they have a nearly identical wax motor inside, and showed the production of same. you can see them mix up the wax and copper powder stuff they put inside. to calibrate the temperature, they squash the sides. you can see the marks on that one in the video.
I found the following in a research paper. It should apply if the wax being used is pure paraffin. But since it has copper in it, the 15% could be different. But 75◦C should still apply.
"Paraffin is a phase-change material that exhibits approximately 15% volumetric change at relatively low temperature (75◦C)."
I'm going to like the first and possibly only video about the inside of a wax motor because it was interesting and may come in handy
Plenty of other people have confirmed the copper is mixed in with the wax for thermal conductivity. It would also add some extra latent heat capacity which would mean it takes longer for the valve to close after the power is removed.
The pin is best made out of stainless steel, because if made of a non-stainless steel it would only take a bit of moisture getting to it to cause enough rust to completely seize it up. Making the pin out of brass would solve the corrosion issue, but running a soft metal against a soft metal in sliding friction like that is a bad combination and it would be likely to seize or wear much quicker than copper on steel.
Interesting.
Thanks for that.
I occasionally still pull something to bits to see how it works, but you have taken it to a whole new level for us in this and your other videos.
Keep them coming.
Thanks again for the disassembly. Curiosity satisfied.
My guess on the copper: aids in heat transfer and "speeds" up action (heating or cooling.)
Great teardown - as ever.
I can’t see how this ‘regulates’ water flow - as a common thermostatic radiator valve would. It seems to be designed to be full on or full off. You mentioned it’s used as a door-lock actuator.
Well, that works, as you want the door locked or unlocked. You don’t want an ‘In between’ state.
But if I want to control the amount of heat from my radiator, I want to regulate the water flow into it.
Wi-fi radiator valves do this. (As, of course, do old-school thermostatic valves.) For the wireless valves, the system controller can work the thermal sums out and set the radiator valve position accordingly.
With this wax motor valve, the radiator will be full on or full off, which makes it harder to maintain a constant environment in a room.
I suspect the power requirement will be higher than a wi-fi valve, too. Once the wi-fi valves have moved onto position, they can turn off. In fact, they are commonly battery powered. (This will be a pig, once battery-life end arrives.) HOPI shows 22 or so Watts to get the heater going, and around 2W on-temperature. If we’re turning the wax motor on and off to turn the radiator on and off to try and keep the room at temperature; there’s lots of on/off 22W heater cycles - not 2W ones. It will be doing many more cycles than a proportional valve.
Also, it’s a mains thingy - so I need new, and possibly unique, wires to each of my radiator valves. That - as an after-house-build fit, will cost far more than the valves !
Where am I coming from ? I want a system in the house which lets me control each room’s temperature. Presently looking at some sort of clever central hub, which lets me say ‘the kids are home for holidays’, which enables their thermostats and heats their rooms accordingly, but within max-min temperature range. ‘We’re going on holiday for a week’ ‘daughter is away for 3 days’ - those sorts of real-world controls.
Each room needs a wi-fi stat, and wi-fi valves on the rads. The hub needs ‘macros’ - a script of commands it executes. Then I’m there, I think. Honeywell have something, but I’ve not researched hard, yet.
Any-road-up, a great video and now I know how these chaps work. Most interesting.
Thanks lots for that.
Matt
I had a 90hp yamaha outboard motor with a wax motor. it was used to control the choke on start up.
It wasn't so much a choke as in butterfly valves to restrict air flow through the carbs but instead the wax motor allowed a direct feed of extra fuel into the cylinder 1 carb, once running it would apply power and the wax motor would shut this supply off in about 30 sec.
A very interesting design in the way it made it very easy to start and it was hard to flood with engine compared to a standard choke
This is the exact principal used in automotive cooling system thermostats.
Thanks for doing this video. Wax motors are also found in dish washers, in operating the detergent cup and rinse agent and some refrigerator ice chute flappers.
This would be what is used for the Thermostat in the car for the coolant valve. I believe the early ones were Bi-Metal but the Wax Motor turned out to be cheaper and was more reliable. They are also much easier to calibrate for a specific temperature range. As the engine coolant gets hot it opens the valve slowly and maintains the the proper engine temp. It is the rubber seal that winds up deteriorating that causes that thermostat to go bad.
Before today, I had NEVER heard of a wax motor. Truly, the American educational system is appalling. Thanks, bigclive!
Ahh but the kids today know about Marxism and and the alphabet genders!
Didn't know what a wax motor was until 7 minutes ago, but I'm glad I watched
I think the copper powder's function is to ensure the entire mass of wax maintains a stable temperature throughout its mass. That way it all goes liquid at once, with no hard spots to impede the operation of the actuator plunger. Cheers!
This man (Big Clive) is simply Fantastic! What a virtual classroom full of "hands on" knowledge one can gain from simply subscribing to, and then, subsequently, paying attention to, all of the very interesting and highly useful information that so freely flows from Mr. Clive's mind to the viewer's ears.
I must respond instep with this posting with a written --> Big Thank You Big Clive
What an intriguing device. I learnt that paraffin wax expands 15% when it becomes liquid, and can exert 1000's of Newtons of force.
Petertronic Productions When water freezes, it cracks VERY strong constructions. I can imagine the same is true for wax.
I just love your voice and your sense of humor 🙂
Excellent, very high quality presentation. Thank you!
Very curious indeed! I entered knowing nothing of wax motors.. I am familiar with thermo wax being used inside Honda GCV lawnmower engines for the auto-choke system (and the fun when it leaks out and machine wont start[and/or the choke actuator arm is siezed]).. Wonderfully clever invention
No power supplies from rare and unusual computers were harmed by short-circuiting their terminals with a bent paper clip in this video. ;-)
Haha! 8-bit guy, right? That was a car crash of a video. Embarrassing to watch.
@@ProdigalPorcupine Yes, it was not his finest hour. The Dremel incident simply added insult to injury.
you learn something new every single day ... good one
I have a wax "motor" that doesn't need electricity to drive it, (so technically it's not a motor!). It opens and closes the windows on my greenhouse, but works in the same way, the sun heats the wax in the cylinder which expands and pushes a ram to open the window, and closes as it cools :)
It's still a motor in the same way that a diesel engine is also a motor. It just isn't electrical.
Motor
1: one that imparts motion
specifically : PRIME MOVER
2: any of various power units that develop energy or impart motion: such as
a: a small compact engine
b: INTERNAL COMBUSTION ENGINE
especially : a gasoline engine
c: a rotating machine that transforms electrical energy into mechanical energy
from www.merriam-webster.com/dictionary/motor
When watching the last video I thought you said "Purple Spring" over and over. Only today do I realise the truth. 🤣
... can you put the wax motor back together so it works again ...???
even AvE didn't cut his wax motor apart
Thanks Big Clive
This is when you call up This Old Tony to make a new casing. He will realize you are kind of dim for asking a machinist to replicate a stamped part, but he will likely be nice enough about the request since he can't resist the chance to squeeze puns out of a wax motor rebuild.
Lol, yes he did.
ruclips.net/video/MiADday0mDA/видео.html
@@c6q3a24
opps! my bad
thanks for the link
ruclips.net/video/MiADday0mDA/видео.html
Great video thank you, I had never heard of a wax motor, learn something every day :)
The main failure mode is the cracking of the rubber separator. The wax can achieve 30,000 psi on expansion, and the copper is to conduct heat and it's very compatible with brass and soft so it won't damage the rubber separator. We use them in radiant floor heating systems. The biggest problem with them is the time it takes to test because of all the delays. On an average house we have a full day or two for testing and adjusting for two guys, so as you can guess it's quite expensive compared to typical zone valves.
Copper does expand more than other metals with temperature changes. But copper is also more thermally conductive. The house my grandmother moved into when it was new in the late 1960's had copper plumbing with both the water and the waste pipes. The waste pipes would expand and make noise through the wooden wall frames in the basement when she drained the kitchen sink of the warm dish water. I use the wax piston openers to automatically open the vent on my knock-down greenhouse for seedlings when it reaches above 68° F (20° C). I store these pistons in the refrigerator when not in use as the temperature in my house varies greatly during the year. No A/C here.
We kept running into gas sealing issues because screws holding down a plate kept losing their seal every thermal cycle. My solution was to dump wax in the blind hole, then let it expand into the space under the screw head when it thermally cycled. Sealed it right up, but required extra tooling so we ended up burying it under adhesive instead.
I found a similar device in my old shower mixer bar .
The device dialled back the temperature if it got too hot .
The copper in the wax is a combination of heat transfer and helping prevent the wax seeping around the seals as the wax is very liquid when melted.
I am thinking the groove in the plunger may be a seal of some kind, but designed to use the air in the groove for sealing/resistance.
Christ, I left that video thinking exactly that thing. Whats the inside look like and then boom, here you are!! Thanks big clive
Honda uses one of these to activate the fast idle (cold start) circuit on their early fuel injected bikes. Always wondered what they looked like inside
Wax motors are used in aerospace to unlock furled antennas, solar panels, etc., on satellites. Power is applied in sequence to the wax motors and, various arrangements of springs cause the antennas and solar panels to unfurl and lock into position.
About the copper in the wax, it's a solid state throttle. The copper would be used for the same principle of starting an engine cold or hot, based on the conditions of the wax, and the copper being a conductor, closer or further apart as the wax is heated, increasing the resistance of the wax's conductivity; it's a thermally conditional power regulator, when it's cold, it conducts the best, when it's hot, it has the highest resistance and conducts the worst.
I've since been told by someone who manufactured these that the copper to wax ratio was used to tune the required travel of the piston.
I'd say the diaphragm improves the force the motor can create. When the wax pushes on the wider area of the diaphragm, it has more total force (force = pressure X area). The force is then transferred to the rubber plug and piston.
And the expansion is mostly during the phase-change, from solid to liquid. That's why they have a very narrow operating temperature. Once it starts melting, the temperature doesn't rise much for it to completely liquify and open.
I nearly scrapped a $1000 front loading washing machine that would not spin. Turned out that the wax motor in the door locking mechanism had failed. Fixed it for $20!
Mid 80's to mid 90's GM trucks used a wax motor to engage the front differential, not a good idea as it is slow. Later then went to a vacuum operated actuator.
@@bobroberts2371 Mitsubishi used a wax motor automatic choke on carburated cars in the late 80's. They worked well, but had a relatively short life. To make matters worse, back then you had to buy the whole damn carb to get a new wax operated choke. Just one more thing that put the stake through the carburator's heart.
@@bobroberts2371 Actually the improved change up design was an electric motor driven actuator, the vacuum actuator was on the earlier model trucks.
@@tomhoehler3284 Chrysler used Mits engine ( 2.6 ) in the K car and smaller versions in the ( Mits ) Colt . The Mikuni carb usually had a bad choke pull off diaphragm that was easily changeable. The decell dash pot orifice usually needed cleaned to prevent a vacuum leak at idle. Never had a bad choke stat though, worked on dozens of these over the years. ( And the Ford VV too )
copper powder is in there to help get the heat into the wax and to increase its heat capacity so that the volume of the mixture changes slower than it would if it were just pure wax. it doesn't have anything to do with the sealing - the wax would wick out those edges if at all possible (regardless of whether it had to separate from the copper powder first).
given the visible travel of the stainless plunger we saw in the last video, i wonder if the flexible seal protrudes into the extension shaft when the wax expands and pushes the flexible puck/spacer into the shaft further than just roughly flush with the shaft orifice into the wax chamber. certainly, the puck/spacer can't be drawn so far into the wax chamber that it gets misaligned with the shaft.
the red spacer seems to be both a way to set the min/max position of the stainless plunger and perhaps a way to protect the puck/spacer from the base of the plunger. aside from those, i don't know why it would be there.
if the flex seal protrudes into the extension shaft, i wonder if that wearing out is one other failure mode. there really can't be that many failure modes to something so simple. the wax could leak, i guess, but everything is at such a high pressure in there that i have to imagine that they get that chamber crimp correct 'forever' or it immediately fails before they ship the part. the heater disk at the end failing or cracking away from the brass chamber i would think is the 99% failure mode.
i find it weird that the stainless plunger has that o-ring groove looking feature. it seems unnecessary for this kind of motor. maybe it's used in another motor with the flex seal and direct contact between the wax and the plunger. or, maybe they use the groove to jig it when they assemble the part. that would be fun to know.
There are wax motors in many cars trottle bodies to control the air flow when the engine is cold. Very simple but effective component.
Nice video, as always! =)
i have a 230V wax motor somewhere in my piles of electric stuff, it was from a room ventilator that had it's blinds slowly opening when turned on, an old "Vortice" model
I have never heard of a wax motor in my life before your video and now I really want one for no real reason besides it's just cool
Cheapest way to get one is probably a thermostatic radiator valve (TRV) for home heating systems.
@@bigclivedotcom thank you now that I know where to get one I just have to figure out an unusual use for one
thank you! I work with these every day.
this rubber plunger @ 3:11. I would suggest its not to absorb force but travel and maintain force. kind of a solid state spring??
Always wondered how they worked!
Thanks, Clive. 😎
Just like a car thermostat! Always wondered what exactly was inside. Thanks! The copper in the wax is interesting. Maybe it is like a built in "stop leak" type of thing.
check out an automotive thermostat. They are used to open the cooling system system at anywhere between 180 and 200F
Looks exactly like a Vernatherm (the core of a thermostat used on engines) Johnson/Evinrude outborad motors use them to control cooling water flow. Interesting to see whats inside.
These operation of these wax motors and car thermostats depends on a solid state phase change (not melting) in the wax as the crystal structure changes with temperature. The wax molecules are idealised as straight n-chain polyolefins, where n is 20+. Above a critical temperature the molecules vibrate and rotate about their length, presenting a cylindrical aspect and the crystal structure is hexagonal, consisting of stacked cylinders. As it cools the wax molecules stop rotating and adopt a flat zig-zag conformation and the crystal structure changes to monoclinic with about a 15% change in volume. There is another smaller volume change on melting. The range of temperature over which the phase change happens can be tuned by adding side chains to the wax molecules and varying their lengths.
I read that the Lunar Rovers and such use wax motors as mission critical parts because they have proven their reliability over the decades in space flight.
My best guess is that the copper is for heat transfer and probably on some level it would be considered 'filler' so that the effect of the wax expanding/contracting would be amplified by the particles just being solid/incompressible.
I don't understand why but you are so entertaining maybe because you remind me of my grandfather (I love you)
Clive and Elves a question with TRV's the oil filled motors (Drayton, Danfoss) are quicker and more accurate at keeping a room at a specific temperature the wax filled ones are cheaper and have a larger temperature spread in turning on and off. Are the electric actuators wax and oil wax for the cheaper ones and oil for the more expensive or is this drivel for they are all wax.
Pretty sure they are all wax, since it's the phase change from solid to liquid (and vice-versa) that produces the density/volume change required to make the thing work. The cheaper ones probably have less of the comparatively expensive metal particles embedded in the wax though, hence their actuation cycles take longer due to reduced thermal conductivity of the wax (also making them less electrically efficient).
@@sixstringedthing The difference between an oil and a wax is the range of melting points.
If I’m not mistaken fire sprinklers use a simile wax motor. They are colored differently for different temperatures. But when there is fire it heats up the wax and it expands opening the valve for water to put out the fire
They either use a lot melting point metal, or a small vial with a low boiling point liquid. A thermostatic valve/wax motor is way too slow.
Robert Szasz thanks for the correction. Similar mechanism (thermal expansion with a gaseous state change?) different medium 👍👍
I guess I really WAS mistaken :-)
I was hoping you would heat the wax motor so we can see the plunger expand. Another great video 👍
He showed it operating in the last video (well, kind of, it takes so long to actuate that he had to jump cut).
This is how a lot of dishwashers actuate their latches... I remember taking one apart with my father once upon a time
Awesome Clive! 👍🏻💯✅❗
This one was actually really enlightening! I had no idea things lioe this were made with wax!!
The copper is added to help regulate the switching on and off, it conducts heat well so the wax will liquify quicker and it will also cool quicker!
I used these to move some shutters inside solar panels that got too hot..they were categorized as pcm (phase change material) linear actuator I do believe
Very informative! Thank you for showing the details of this!
The rubbery plastic plug is probably to protect the rubber disc when the wax expands, so it isn't pressing against anything hard which could perforate the disc.
Yes, the Copper is for aiding thermal transfer, decrease lag in the actuator.
Just had an epiphany while reading the comments.
How about the copper particles in the wax expand too, and exactly compensate for the slight expansion of the outer case! So keeping the volume INSIDE the case the same at all temperatures. Then the wax expansion sums just work with a constant volume.
I am unanimous both that this is brilliant, AND that I am the most modest person commenting here.
Many people can’t see this ...
Love your work Big Clive
I'd assume the copper would be for even heating
Or to tune the melting point. Maybe the temp they want is the melting point +3° so they have to mix it?
Big Clive is going to start a waterjet channel
IU was wondering if the copper in the wax could be for electrical conductivity as well as thermal. The other thought that went through my mind is with regard to coefficient of expansion. IE the copper used to "tune" the wax expansion coefficient.
SU Carburetors i.e. the HS4 use these things in so called 'waxstat jets' to lean the mixture if the motor is hot.
Why are there so many different colors of wax? Are they different materials or is that just the structure of the impregnated copper leading to structural color due to crystallization or something?
When I dremeled it in half the wax was contaminated by the rubber from the seal.
@@bigclivedotcom Ah, a disappointingly mundane explanation. :)