Clever Uses Of Thermal Expansion
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- เผยแพร่เมื่อ 3 ก.พ. 2019
- Clever Uses Of Thermal Expansion
On any given day, we rely on dozens of hidden computers seamlessly integrated into our lives to function. The low cost, flexibility, and ease of rapid product development of embedded microprocessors have fundamentally changed how products and equipment are designed; finding their way into even the most trivial items.
In this series, we explore how engineers accomplished design goals in a time long before the semiconductor revolution by spotlighting ideas that combined brilliant engineering with innovative uses of material properties.
Thermal expansion is one of the more common physical phenomena we experience daily. Most materials expand when heated. When a material is heated, the kinetic energy of that material increases as its atoms and molecules move about more. At the atomic level, the material will take up more space due to its movement so it expands.
THERMOSTATS
Most vehicle engines operate best around the boiling point of water. Keeping the heat generated by combustion in thermal check is a liquid cooling system that flows coolant in a circuit between the engine and a radiator. Typically the cooling system capacity is large enough to cool the engine at all mode of its operation. But when a cold engine is first started, this cooling capacity becomes a hindrance, as it can overwhelm an engines ability to rapidly warm up to operating temperature. Thermostats are used to regulate this temperature.
BIMETALLIC SWITCHES
Mechanical control by thermal expansion is simple and very reliable but what if we need to perform a nonmechanical form of temperature based control, such as electrical switching.
In a manner similar to wax, metals expand when heated, though different metals expand at different rates. This difference in expansion rates allows for some interesting applications. Bimetallic string bend when heated and can be configured into electrical thermal switches.
FLASHERS
We can expand on the functionality of bimetallic switches further by mounting an electrically resistant heating element to the bimetallic strip. As current flows through the heating element, the electrical resistance causes dissipation of heat, raising the temperature of the bimetallic strip. As it heats up, the thermal motion causes the bimetallic element to switch on the flow of electricity. Current is shunted away from the heating element, cooling it. The bimetallic strip then contracts back to its original state. This opens the switch, restoring current back to the heating element. This cycle of opening and closes forms a thermal flasher.
COIL THERMOSTAT
Bimetallic strips are durable, easily formed and can be used in various configurations. If we coil a bimetallic strip, the thermal motion causes the coil to tighten or unwind, creating rotation. If we calibrate the motion to the temperature of the bimetallic coil we create rotational motion relative to temperature. Add graduations and an indicator needle, and we now have a dial thermometer.
This simple, purely mechanical mechanism not only allows for measuring temperature but also the ability to control it in an adjustable manner. This is how residential, non-electronic adjustable thermostats operate.
THERMOCOUPLE
Combining dissimilar metals for the purpose of temperature sensing also comes in other forms. When a junction between two different metals are formed, such as with the alloys chromel and alumel, the thermoelectric effect occurs. An electrical potential difference across the junction develops with the voltage changing in a temperature dependent manner. This is known as a thermocouple.
Thermocouples are simple, rugged, inexpensive, and interchangeable. Though they aren’t precise, they are used as temperature sensors for both simple and digital control systems.
Other industrial configurations of control by heat exist, though these methods are more integrated into systematic designs, that are impractical for direct electronic control, they employ thermodynamic properties of working fluids such as air, combustion gases, steam or molten salt and as are generally used for power generation or transmission.
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3:12 I know this is a serious video but I wasn't ready for the lips on Celsius
Painter: Sir Celcius, the portrait is complete.
Celcius: Let me look. Oh! Dear, those lips are so pale. Could you make them a bit more...👄
Luscious
I wast just gonna write that xD
I just appreciate that Santorio Santorio and Gallileo Gallilei were BFFs. You know, hang out, crush on Marky Mark, whatever.
The thermal switches for turning lights blew my mind ! I had no idea !
Steak Saignant same here. My 75 needed a flasher relay, it would get stuck with the lights on.
I have been thinking it's an RLC oscillator for so long.
glad , im not the only one...
i actually went bananas....
Cool video. Was expecting something about manufacturing processes using thermal expansion like mounting bearings, but this was very intresting too.
Cylinder sleeves are installed by heating the cylinder and installing a cold sleeve
If we are mentioning heat uses on metal, wheel bearings on solid axles (possibly but unlikely wishbone) need to be put in the freezer so they shrink and can fit into a wheel hub. I'm assuming a wishbone doesn't ever need to be chilled is because conical bearings are cone shaped ∆ and self align. This is from my single experience doing a 1976 Fiat 124 bearing and hub job.
Agreed, that was my first thought as well
Yup. The ring gear on flywheels are sometimes installed by heating the ring gear, placing it on a cold flywheel, and then letting it cool and contract.
Perhaps the video title should go something like, "The thermal mechanics of thermostats". I would still like to see a video about thermal manufacturing
Regarding failing safe, I couldn't resist quoting John Gall from 1975, "When a fail-safe system fails, it fails by failing to fail safe." : -)
God damnit that quote is brilliant.
And that's why I have a fail-safe thermostat in my truck that fails to safe!! :)
Humorous, but it's true. Too often, people will remove a fail safe circuit and replace it with either nothing or something they created that does not work. Lots of houses have burned down because the homeowners messed with their water heaters not knowing what the hell they're doing.
Who is John Gall?
@@bcubed72 Don't be lazy. Google is your friend, O person of no content channel.
I gotta say, you earned my subscription. Your format is direct, factual, and well rounded in general. You answered pretty much every question I had about thermocouples, and bi-metallic switches. Thanks for your hard work!
hi, im a power plant control room operator. i know alot about what this video is based on and i think it may be the best demonstration of the physics involved that ive ever seen during my schooling. bravo, you got a new subscriber.
Thermal switches in blinkers typically have the resistor and bimetallic switch in series, so the light goes on immediately when you turn the blinker on and turns off once the resistor heats up enough. Also thermal switches in blinkers slow down when a light bulb burns out, as the current through the resistor decreases and it takes longer for it to heat. Relay based blinkers usually speed up when a bulb burns out. And the rate change isn't an accident, it is there so the driver notices when a bulb burns out.
Phino K.M. Indeed. And newer vehicles (e.g. EV) with LED turn signals have the audio synthesized to provide that feedback to the driver
Always wondered why they sped up when they were dieing. Great info
My brain died when he said when one bulb fails more power goes through the resistor... But... the resistance is higher now.
It will speed up. Thermal inertia plays a role in it. If you have 2 bulbs on and send more power though the strip, you end up with more hear stored in the heater and the strip and it goes a bigger distance. If you have less heat, it will open less far apart and cool faster too.
I get your logic with the slower turn-on, but tell me, how would it cool down slower and turn off slower if you had less power and thus less heat though it with a single bulb?
The thing speeds up.
@@airgliderz Say you have 2 bulbs at 1 ohm in parallel and one blows the resistance goes up (from .5 to 1), unless car blinkers are wired in some wierd way then idk.
As a teacher of Physics, Chemistry and Electronics etc, may I commend you on your explanations. They are clear, simple and well presented.
This is like mechanical logic! I really like the way you approach the subject. Direct, simple, concise and precise
Also, I subscribed after this video. I found your contents really valuable
As a Materials Scientist let me add to what you note.
A lot of phenomenons can be shown as a physicl representation, just like chemicals can be used to demostrate natural ideas. Teaching science to kids one uses anyway to show a phenomenon.
This video shows the simple ways that are employed to make things work. Technologist use the understanding of material properties to our benefit. Series like "THE Secret Life of Machines" explains concepts further.
remember most things operate on simple ideas.
@@emanuelmifsud6754 thank you for your input! I will definitely take a look. Greetings from Portugal!
all those Minecraft mods are starting to make sense
honeyspoon that’s actually hilarious
xD
Automotive cooling systems are pressurized around 14-16 psi raising the boiling point an extra 45 degrees. I enjoyed the video I just wanted to offer this information to you.
Also the composition of the cooling fluid increases the boiling point...
An extra 45 deg C? No way.
@@rogeronslow1498 as he was mentioning a pressure measurement in psi, I think he is talking about fahrenheit.
@@marcusrauch4223 lots of people use psi for day to day pressures and SI units for non pressure measurements.
@@rogeronslow1498 Simple check on Google tells us that radiator additive concentration can increase boiling point to 121deg C to 125 deg C. As a Material Scientist I like to keep to correct units mainly the Metric system.
An interesting use you didn't mention: thermal expansion is used to join gears, wheels and other rotating objects to shafts/axles. The wheel and shaft are made to slightly overlapping diameters, then the wheel is heated and expands and the shaft is cooled so it shrinks a bit. The wheel is then slid onto the shaft and when the parts cool down/heat up to room temperature, the wheel grips tightly onto the shaft.
The quality of content is up there with Kurzgesagt. I love this. Keep it coming!
You might want to check out "Real Engineering", then. Nothing but quality stuff.
@@lefr33man I'm subscribed to RE already (on my other account), and I love his content! Thanks for suggesting though! You're doing real good by spreading some channel names around.
For machinery purposes of very tight component assembly you've forgotten the ''interference fit''.
Cooling the shaft and heating up what ever goes onto the shaft.
He didn't want to create a full length feature.
Also missing is the analogue problem of Hysteresis (or lack thereof...). E.g. without designing in a type of 'dead zone', a thermostat would rapidly switch on and off wearing out not only it's own electrical contacts very quickly, but also the equipment used to perform the heating and/or cooling.
Are you a millwright? This is a common task. Heat and cold help a lot.
50+ years on this planet and I never knew exactly how old school car flashers worked 🤔. Great quality content, this was my first video by you and looking forward to more.
61 here. I didn't know either. But there must be additional cleverness, too. Those flashers have to work on a freezing cold winter night in northern Alaska, but also on a sweltering hot day in sunny southern Florida. Somehow the limit temps have to follow the weather.
The degree of enjoyment i get from these videos is palpable.
This is incredibly cool! I took some beginner Electrical Engineering classes as part of my computer science degree, and knew a little about this sort of property and applications of it, but most of this content is absolutely brilliant stuff that I've never heard of before!
Just watched a few other videos, and Definitely agree with another comment on here that the quality of this channel's content is up there with Kurzgesagt and Real Engineering. Fantastic!
As a software engineer, the thought of replacing analog mechanical controls with sensors and software terrifies me. The question in software engineering is "what happens when we screw something up?" not "what happens if we screw something up?"
Started watching your channel around a week ago and I'm absolutely addicted! You make some of the most interesting and best produced documentations on TH-cam! Keep going!
So that's why car indicators flash faster when one of the bulbs has blown!
I learned something new today. Thank you New Mind.
I noticed the music volume when you show your intro logo has been too high for nearly all your videos; it's always jolting, especially with headphones. For videos so focused on precision, I'd think you'd try to match the levels more. And honestly your intro music doesn't really fit how relaxing the rest of your channel is. But other than that I love the content.
I like the intro music and video music, perfect volume with headphones, phone or PC speakers. Dont change a thing, great helpfull, interesting, realistic, applicable to every day life videos. .
@David MO sounds like it's time to get your ears checked
agree.
I'm watching this using random 20€ Logitech speakers and it sounds too loud
If it was in reverse it would build up to being too loud. Instead it's instant too loud and fades to normal.
Regardless. It's too loud.
This is constructive feedback. I love the channel and will put up with the non-normalised intro sound, but it's truly there all the time.
Just started watching a couple weeks ago, top quality content! Have loved all your videos so far, keep up the great work!
I am enjoying the time spent watching your videos +sub ... thanks for taking the time to make them
Dude, your channel is great! You pack a substantial amount of information into these short videos, while still getting it across in a concise, understandable way. TH-cam's algorithm really needs to pick up on your channel already. You should have *far* more subscribers than you do.
Thanks! You just got here. A week ago I only had 5k subs
@@NewMind Okay, that's good to know. So the algorithm has noticed you!
I just discovered this channel I just wanted to say how much I love it. Criminally low numbers
This was a really professional and well put together video and the content was very interesting. Good work.
Really interresting video on a great channel! I really enjoyed the mix of live demonstrations, animations and historic images. Well done- I know how much effort that all takes!
Thanks, for the motivating and supportive words!
What an amazing video to show just how awesome these simple hidden little gadgets are that most people don’t even know exist and to show just how incredibly necessary they are in our daily lives, the ability to harness thermal expansion is truly incredible, well done, I love it!!
I'm glad I found your channel. Your videos are really informative and high quality. Thanks for the great work and keep going!
Nice stuff, haven't heard of some of the mechanisms yet. Something that I missed would be shrinking bearings, gears, couplings etc. onto shafts by heating the piece and maybe cooling the shaft. They then slip together nicely and after normalizing in temperature they clamp extremely tight together. In a similar fashion there are also heat shrink collets for holding endmills and other tools, there are even special inductive heating devices for inserting and removing the tools from the collet. They are really compact and stiff while also being very precise.
Generally, unless you have the extra equipment or need a really interferenced fit but are limited in heating the outer, cooling the inner is avoided because it will condense water out of the air and you'll end up rusting the parts.
One workaround is using a purged box with something like nitrogen. Now there's no moisture in the air.
Wow 55k already! That is awesome , congrats and well deserved.
Really awesome video! Keep it up, and you'll be a big channel soon. The quality of the video and animations are really top notch. While your explanations are fantastic, with great pace and delivery too. 10/10.
thanks!
This is hands down one of the best channels in this field. Content quality and story telling is top notch! Keep up the great work! I honestly see this channel getting million+ subscribers! Good luck!
Another great video, keep it up. Really looking forward to part 3 on your microchip series!
It's in the pipeline. Had to divert a bit to mix up the content but its coming. Thanks for the support.
I recently discovered this channel and started watching all videos from the beginning. And each and every video surprises me of how great quality it has. I really learned a lot watching this video. Thank you and please keep making high quality videos.
This channel is by far the best I follow on TH-cam. You're great, man. Wish I found it earlier
Fine quality content, glad I found you.
Great video, you break things down really well so that even I can follow it. Much appreciated
Learned so much! Thanks!
Your videos are amazing! Keep up the great work!
Peaceful video, quite relaxing.
When I was like 13 I a family friend with an HVAC business showed drove me around and I learned a thing or two. One of the coolest things I will never forget is when I learned how the thermostat double metal coil thing worked based on temperature, and it bending into itself to become a switch. Something about it being such a simple concept really made me appreciate the modern world, where everything is so complex.
the bimetallic coil also used to be used in carburetor chokes, making them open when the engine is hot enough to need more air.
Got recommended here, great channel you got going here. Keep up the good work, got my sub.
Great video, you really know your stuff! I learned several things about systems I thought I understood well, can’t wait to see what you put out next.
Thanks!
Most thermally activated switches I've seen don't use a separate heating element, but instead rely on the current passing through the bimetallic strip to generate heat.
Fantastic video with clear and concise explanations and examples. Thanks for the effort you put into this!
I love your videos, you can tell you work really hard on them, you have so much information and you explain it so that it's easy to understand which is not an easy thing to do.
Great videos. Subscribed!
WOW this video is so well made, although simple enough, the diagrams explain everything very clearly.
Definitely digging your channel. Keep it up!
This was neat as hell, thank you for the video
I think I just learned more in 10 minutes of TH-cam than 7 hours of high school
Vlad Caso no
@@manumalhotra3520 wut?
Should have layed of the weed in high school
Isnt that the truth. I learn more from interaction with real world application of math and science. Want to learn math build something. My spelling is terrible but my math got a whole lot better when I started to build stuff. People used to learn hands on and many an invention came about by nessessity.
High School is just about teaching your the bare minimum to make it easier to be introduced to actually learning things. Thanks to school you are at least aware thermal expansion exists, you know how a thermometer works, you at least have an idea of what temperature actually means. You have a very basic level of knowledge like that, which is enough to be easily introduced to stuff like how a thermostat works.
This might be one of the most informative videos I've seen yet. Now I understand how a salamander's thermocouple works.
I’ve just learnt so much from this video. Thank you!
I think this is underrated channel..This deserves much more subscribers...
What a great video and channel. You should have way more subs!
I noticed you didn't ask people to like/subscribe, and it was refreshing so I did just that.
Added to the minute list of videos that have blown my mind.
Wow… Super good video!!!! You did a very good job of covering the topic at hand!!!! Well done. I will watch a few more of your videos…
Awesome video! I've never thought before how a dial thermostat works, but that makes perfect sense. If you happen to know, wouldn't that make the metal very brittle or build up thermal stress after enough exposure though?
Thanks! So short answer yes it does, but how much and how it affects critical bimetallic parts is a complex question, as it is determined by the alloys, the formed shape and even the method of bonding.
I knew how thermocouples and thermistors worked, but the rest of this stuff kind of blew my mind. Great video!
Great video and wonderful illustration.
What a beast of a man for making such a good video
Your videos are amazing, please keep doing what you're doing...
Unbelievably good video!!!!
Just subscribed after watching 2 of your videos! So much to learn thanks for sharing!
Very educational. Thank you. 👍🏼👍🏼👍🏼
I just found out what makes the clicking sound in indicator lights and its changed my life now
Thank you for your knowledge!
Very good explanations and well presented.
Très bonnes explications et bien présentées.
Wow that’s amazing. I always wondered how they worked
When people ask what's my major (materials engineering) I'll send them this video
A Nice Revision of what I learned In my engineering 🤘
Learned most all of this as a teen, but always cool to watch it explained again. Good vid.
One of the best uses of heat control that amazed me is rice cookers.
Because a magnet will fail once it reaches a certain temp you can pair it so it fails at 101 degrees. Because water boils off at 100 degrees it will only turn off once all water in the pot is gone (absorbed/evaporated).
your explanations are absolutely amazing.
I've always wondered why the frequency of a turning light in the car variates with the variation of power consumption (watts) of the bulb you are using.. here is the answer! Great job
Thank you!!!
Well made video thank you! I am a new subscriber this was the first video of yours I watched!
Great content really enjoying your videos.
Engineers are the heroes of the modern world
One of the best examples of this is all of the expansion joints on the SR71 Blackbird. This engineering marvel literally leaked fuel while onto the ground and continued to leak while in the air until it reached high temperatures on its outer skin through high speed flight. There were expansion joints all over this aircraft. They figured this out without computers or calculators using slide rules by hand. To this day this aircraft holds the speed records it has achieved to this day. Amazing what people can do when they are faced with these huge problems that they face.
Cool, that intro train shot is just a 10min walk from here!
I was kinda expecting a video on 'Clever Uses Of Thermal Expansion' to be more than 12 minutes of basic info on thermostats - almost all of it on bimetallic types, which is the second most basic and commonly known use of thermal expansion (#1 being expansion of a liquid, e.g. in a mercury thermometer). The only thing I actually learned was about the wax-melting variant.
wow man you're a genius maybe you should make a video
That frustration happens when you're not the target audience. As you pointed out that may be basic information, but to someone who never thought about termostats the video was perfect - and the title interesting enough for us to play the video.
@@GabrieldeOliveiraAzevedo Fair enough, but I expected 'Clever Uses of Thermal Expansion' to include a) more than one use, and b) that are notably clever. Say, industrial process control methods that use the change in density of the working material to regulate operations, or fitting metal pieces together by heating the outside piece to make it larger then letting it cool and shrink around the inner piece - both of which are things I know exist but would be interested to known more about. This video should have beet titled 'How thermostats work'.
So glad I found your channel. It is the best there is. I saw a comment on another video that you also grew up watching modern marvels etc. That is exactly the niche you're filling. Mainstream TV ain't got shit on your channel. Thank you.
That was some interesting content. Then you very much
I'm happy I came across this channel..
Excellent video. Thank you for info
I love the premise of this channel
thermocouples don't use thermal expansion they use the thermoelectric effect. most electrical sensors (RTD, TC, diodes) don't use thermal expansion either.
Missed the Sunbeam toaster, lowers the bread and raises it using thermal expansion.
Chris Yu Didn’t the video mention the thermoelectric effect?
@@RandomNumber141 Yes. 11:00
That's why he said, at 10:50 or so, that "joining of two dissimilar metals for the purpose of temperature sensing can also take OTHER forms." He then elaborated on the thermoelectric effect himself.
Just one thing about those flasher units for motor vehicle turn signals. Where do you put the blinker fluid? Also, are these flasher units optional extras for BMW owners? :)
7:14 it will short circuit : )
move it in front of heating element : )
Thanks for your Videos : )
The amount of effort you have put in making this video is unbelievable! Hats off to you bro! Deepest respect from a mechanical engineer.
super interesting, thanks!
Very Good!
There was once a fully automatic toaster that used the thermal expansion of heating elements it used in order to lower and raise the bread, along with a bimetallic strip to turn off the power as the bread got toasted, I believe this is also a great another great example of thermal expansion
Anyways, great video
I believe that toaster was made by sunbeam.
Technology Connections has a video showcasing that toaster, should check it out if you haven't seen it.
I think that sunbeam toaster didn't use a timer, it detected the amount of light/heat reflected off of the bread to figure out when it was done.
UserNameAnonymous Nobody mentioned a timer here, only a bimetallic strip
@@AL_O0 - ah, maybe the "eye" used a bimetallic strip also. I thought you were referencing a bimetallic strip timer mechanism. My bad.
keep it up. good content.
This is a great video! I learned a lot haha
Ohhhh boy i got an idea :D i'm gonna make a thing with thermometer coil that lets out some creaking noise when it cools. And then hide it in some creepy place i don't know yet where. So when the air cools it's going to creak just barely audibly, and people will think some ghost made the air cool and stepped on a floorboard or something :D
I was expecting a Minecraft Thermal expansion tips and tricks but boy this is cool