TechStuff Classic: How Clothes Dryers Work

hand in hand with the how washing machines work. If you've been listening to these classic episodes, you know, a few weeks ago, I did that one, but you know, well that one left me all wet. This one blows me away, puns. Let's listen in. So, what was the first clothes dryer? Lauren? The Sun? Yeah, that thing is just pulling so much double duty. I mean triple duty, like like Quinn tuple duty. What what above? Quickly? Yeah, like infinite duty. Yeah, there's a lot of duty going

on with the sun, including drying our clothes. So clearly, if you've ever had to dry close without having the use of a dryer, I've done this. I think a lot of people have done this at some point or another, maybe fewer today than back when I was a kid. But it depends on where you live. If you're in the middle of a city, perhaps yeah, maybe not so much.

You might have gone to a laundromat or something. But most of if you look at history, most people use the sun in some form or another by laying wet clothes that have just been washed out on on on a rock or hanging it on a line or over the branch of a tree and just letting the sun do its thing evaporate all that water. Usually take you know, a couple hours, um, depending upon where you were at,

how hot it was, how humid it was. Humidity could slow things down, obviously, but not only dried up the clothing. It would also cause colors to fade over time, sometimes pretty quickly, depending upon the dye being used. Now, sometimes you plan for that, that was what you want it. In fact, the Romans used to use various types of minerals and rub them in on the cloth. They would make during the drying process an arctic to um specifically

fade or or even bleach it. Yeah, so that way you get that nice white toga look um, and then you can go to all the parties. Because in Roman times they were all toga parties. Okay, I was gonna see if I can get an eye roll, but instead of Lauren just gave me the staring right into my soul look, which is terrifying. So we're gonna move on. Okay. So, so wash your technology evolved, Um, it really intricately, as

as you may have heard in our previous episode. But since the sun is relatively effective and drying clothes this way is not really difficult, backbreaking, time consuming work, dryer

technology didn't really develop along the same lines. Yeah, it just it wasn't as big a deal because yet to wash something you had to put in a lot of effort, right, you had to, especially before the washing machine, you had to scrub things manually or stomp on them or beat them against rocks or throw them away and get new stuff. I mean, it just was not easy to do, and so there was a need to develop automation there. It just it felt like there's this is so much work.

It's it's the woman's dread, as we said in the last podcast. According to one quote, so that made sense. But for drying, like you said, it was, it was free to dry it by the sun, so you didn't have to you know, put in any kind of expense there except maybe for a clothesline and maybe some maybe some closed pins, but that's about it. And uh yeah, you just had to lay it out and collect it.

That's all the labor that was involved. So it wasn't as important to develop a dryer, but it didn't make things convenient, right, You couldn't have dry clothes very quickly using that rate. So if it happened to be raining or something like that, Yeah, so there certainly were people who were thinking, there's gotta be a way to dry clothes even if the weather is bad, or to do it more quickly than just putting them all on the sun for a few hours. And I'm sure that a

lot of people were doing this. But the story of this kind of thing is a wee bit contentious, as we find out every time we look into the history

of something. Yeah, as it turns out when you want to look at the history of something that's been around for at least a couple uh like like a century or more, and especially something that was done by the lower classes who were not writing about it or or certainly not contributing to scientific journals very frequently, or perhaps didn't bother to patent something, then it's hard to find reliable records. So here's a big caveat for all the

historical stuff you're about to listen to, dear listeners. The caveat is that we did a lot of background research to try and verify as many claims as we could, and a lot of them are unverifiable, meaning that there are no primary sources that are definitive. There are a lot of sources that quote each other, but it becomes kind of a circular thing. Yeah, which does happen on the internet, not entirely and frequently, um, but so so, most of what we're going to tell you comes directly

from the U. S. Patent Office. That's what I relied upon most heavily. Although our first example is not among them because it wasn't a United States invention. It was actually a French one. This is when you're going to see if you ever do a search for the history of dryers, this is going to pop up all the time.

Usually the year is specifically seventeen, but the best I'm going to say is around the year eighteen hundred, a French inventor known only as post Shaun p O c h o N sometimes listen as M. Posh On, but I believe the M is for Monsieur Poshan, not necessarily a name that begins with him created what he called a ventilator, which to me sounds like a weapon you would pick up in Duke Newcombe. But in this case, a ventilator was a metal drum that had some small

holes in it. So that might start to sound familiar already to anyone who's used a dryer. And you'd put your wet clothing into the drum and turn it using a hand crank, right, and you think, well, okay, so now you're just turning a drum full of wet clothes with holes in it. What else you have to put it near a fire, yeah, as your source of heat.

Now here's the thing. Um. Sometimes this meant that clothes would get a little uh you know, burnt, Yeah, a little little extra crispy um or or full of smoke in any case. Yeah, so you would end up damaging clothes this way, And according to most reports, this is the first tumble dryer, but didn't catch on mostly because of the downsides. Right, the idea that you would end up damaging clothes, Well, if you're gonna damage them, then

that's not helpful at all. So the interesting thing to me is that this basic approach that he took ends up being the kind of the central design of dryers in the future. It would just take a long time to perfect the heating elements. Years. Yeah, so sorry, but yeah, but it's interesting that again, we couldn't really find any primary sources on this, so this story could be apocryphal. How I her, I'm going to go ahead and say that it sounds like it's possible, so we'll give it

a pass. Sure, then in this is the next really official dryer technology that we have to report on, and it's one that we actually mentioned in our episode about washing machines. That's when um Ellen Edgley invented a ringer to sit on top of washing machines and help dry out the laundry before you hang it on a line. So so that's that's squeezing mechanism to the two rollers, and it rolls the clothing between and squeezes them with incredible pressure that could crush your fingers if you get

them too close. Don't do it right right. The design would later be integrated into washing machine models. Until these tumble dryers later caught on. Yeah, soo, we have another African American inventor, this one by the name George T. Sampson, who filed a patent for a clothes dryer. In this case, he spelled dryer d R I E R, which some of the patents are in that spelling. Some of them are d R Y E R I. Can do what

they want. Yep. His invention wasn't a tumble dryer, however, although I saw a lot of notes that said it was an improvement or, in the case of some of them, a betterment of Poshan's approach. Uh, it wasn't wasn't like, No, it wasn't a tumble dryer. The I think the betterment or improvement would be that he used a stove as the heat source as opposed to an open flame, so it reduced the kind of damage that could happen. But yes, he as he pointed out, it was not a tumble dryer.

It was not like a drum that you put clothes in. It was more of a frame and you would put the clothes within the frame, secure it in the frame, and then put the suspend the frame near the stove and the heat would would end up evaporating the water out of the clothing. So, uh, it's in that pattern, is in the records, so you can actually go and look at it. And if you look at it, you'll see it is not a tumble dryer. It's not the same style as posh on. So that tells me something else.

It tells me that some of the websites that I pulled up while I was doing this just didn't go and look at the patents. They just reported it as being like this was an improvement on that tumble dryer, and always go that extra step your research. Guys. I'm saying that to all of our listeners because I expect that they will occasionally have to write things like if you're a student, you may have to write a paper.

This is why taking that extra step, Like if you just find a web page that says it's about that stuff, see if you can find a primary source, because it's always going to give you a better idea of what the real story. Yeah. Then we have a patent by Seward H. Davis for his clothes drying machine, and it's interesting. So now he's decided to incorporate an oven directly into the device to generate heat. So we're still creating an oven.

It's pre heating air because obviously an oven's not going to generate heat at the speed where you could just blow air across it and it's going to be hot, so you would. But he also incorporated a motor in his It was a motor that was connected by pulleys to a rotating drum. So going back to that post on approach right, and it would rotate in one direction

for a few turns and then go back the other way. Yeah, because according to Davis, you didn't want to continuously rotated in one direction or else the clothes would become hopelessly entangled with one another, and uh, it would just end up being a big mess. So his design had it where it would rotate one way then the other, and that would prevent the clothes from getting, yeah, from clumping

and getting all like super friendly inside the dryer. You want your clothes to be a little bit antagonistic, Yeah, you don't. You don't want any fraternization inside the tumbler,

is what I'm saying. Um, So, yeah, pretty interesting. And then he also he also specifically pointed out in the patent that the whole idea was to allow the clothes to fall, to tumble, like you didn't want to just spin and try and force the water out, but to tumble, because that tumbling motion would have it go through that hot air and thus evaporate the water much more quickly, pushing the air through it. And therefore sure, yeah, yeah, kind of cool. Nineteen five Henry Sieben he attempts a

different approach. His patent has a closed dryer that is more like a heated cabinet with wire shelving inside it. So imagine that you have like a little like cabinet or closet and it's got wire shelves, and you put the clothes on the shelves, and then you have an electric fan that draws air through the machine, which allowed

for faster drying. Now, he didn't specifically include an element that with heat air, but you would presumably have this near some sort of other device that would heat the air, like a stove. So this cabinet would just pull the air through, which would circulate through the clothes. So kind of similar to Seward H. Davis's approach of tumbling, but they're stationary, so it's just pulling the air. So again this this another idea that becomes important in uh in

modern day dryers. So the important thing to remember here is the fan that pulls the air through. These are all various elements, the tumbler pulling the air through. These are all things that are going to come into play with the modern day dryers. Now out you still had to preheat the air though with something like a stove. Then we get to nineteen thirty seven. Now here's the guy that most people credit. Yeah, although again the citations

different from what I was able to find. Okay, see, because he filed for a patent in ninety seven, this is James are more. James are right? Thank you. Um, it wasn't granted until, which we suspect world War two probably had something to do, had other stuff on their minds, right, the patent office was probably drafted. Uh So yeah N seven is the filing and is the awarding makes perfect sense. But it was for a closed drying machine. And this is the basis for closed dryers as we now know them.

And so he what he did was he added applying heated air that didn't need to be preheated in an oven. He wanted to have a heating element either gas powered or electric, and in fact would eventually create both types. Right. He He also created a ventilation system so that air can can move through the dryer and then exhaust out of it, carrying that water vapor out. So you see, this is the combination of that rotating drum and that idea of the cabin exactly. So by combining the two,

he has the best approach. And in fact, you could tell us the best approach because it's the one that lasted the test of time. So yeah, he uh has often cited in a lot of the websites we saw as having patented this this approach as early as nineteen thirty. But I went to the patent office, I mean online to the patent office. He didn't like, you didn't go there. I didn't actually take a trip to the patent office. I think they probably would have thrown the out of

the patent off. They were like, how did you find your way in here? And it's like, I'd like to see your archives from nineteen thirty. Yeah, that probably would not have gone over well. They said, you've heard of the internet, right, Well, you can actually do searches online on the patent office. Google has a Great Patent search function, but you can also go to the U S Patent

Office and use their search function. I use both because I could not find it in one, so I wanted to try both versions in case you need to find a keywords pretty pretty acutely. Yeah, but it but it's it's a little more forgiving. But with the US one you can find everything listed in chronological order, whereas with Google you get it by order of relevance to your query.

So in other words, you might see the first one pop up and say nineteen forty five, and the next one says nineteen twenty seven, and the next one says nineteen eighty three, and you're like, oh man, it's gonna take forever to find the oldest one. U S Patent does it chronologically, with the oldest being the last on

the list. I went through both. The earliest I could find was nineteen thirty seven as a filing date, let alone a patent granted date, So I have no idea where they pulled this date of nineteen thirty They also said that he sold the patent in nineteen thirty six, but he didn't even file for a pat until nineteen thirty seven. I don't know where you get your information Internet. You should check it more carefully. Yeah. So, anyway, he did file in nineteen thirty seven and he did end

up working with another company in nineteen thirty eight. That company would be the Hamilton's Manufacturing Company located in Two Rivers, Wisconsin, Pride and Joy of Wisconsin of Two Rivers, Wisconsin. Anyway, they actually have a museum dedicated to this former manufacturing company and they used James R. Moore's design. They actually paid him for this, and they released in the June

Day clothes dryer based off this design. The early models used gas for heat to heat the heating element, so you'd have to like light the pilot light every time you wanted to dry a load of laundry. And then once we were done drying that load of laundry, should probably remember to blow it out. Yeah, you had to extinguish it or else you would just be wasting lots of gas or possibly creating a fire hazard, which, by

the way, dryers big fire hazards in general. Do not run your dryer and then leave the house just in case. I mean, I don't want to scare anybody, but it is, but linked fires can happen. Yeah, so just a little word of caution in the middle of the episode. But yeah, later models were electric and they still created the gas ones too, but manufacturing was interrupted shortly after they started.

They produced about six thousand of them and then stopped suddenly, all because of the event we have already referenced in this podcast, afore mentioned World War two. So world War two causes a manufacturer to stop. This was the case across multiple industries because, yeah, the war effort needed all that material and and labor and a lot of the factory space. Yes, so all of that meant that dryers were not seen as being important to the war effort.

It was put on hold. World War two was was over and the Hamilton's Manufacturing company got back into this, but they were no longer the only game in town. By this time. Another big company, much bigger than Hamilton Manufacturing actually got into the closed dryer game, and that would be General Electric. And so then it was off to the races. But but not not fast races, and not cheap races. No incredible expensive races, very very slow,

expensive races. While we're tumbling around inside the clothes dryer, I thought maybe we should take a quick break, we'll be right back. Around the same time, the first electric dryer to include a glass window in the front was introduced. And this is a design element, you know, it's it's it's just kind of nice to look at. But I wanted to mention it because it was designed by Brooks Stevens,

who's another Wisconsinite. He was a Wisconsin designer who also worked in an architecture, furniture, and auto design, including that greatest car of all, the Oscar meyer Weenomobile. Man. Truly a visionary. We could do a full episode just on that. Actually I should mention all the inventors we've talked about have done some pretty phenomenal things besides inventing dryers. So but this, I mean, no one approached creating the Oscar Meyer Wiener be Also, you know we won't go back

and fill those out nineteen fifties. Well, according to the Bureau of Labor Statistics, a dryer in the mid nineteen fifties cost about two d thirty dollars, which if you adjust for inflation, would be closer to two thousand dollars for a dryer. Yes, so not a whole lot of

people could afford it on um. I shall also point out that this same paper cited some of the erroneous sources that I mentioned earlier, um, the ones that could not be supported by saying the patent office, I guess the Bureau of Labor Statistics in the patent offices don't don't talk to each other frequently. Yeah, this inner departmental stress type thing. This was I had to include it. I mean, there are some crazy patents out there, y'all.

If you if you ever have a really slow day and you just want to amuse yourself, just start typing random words into a Google patent search and then enjoy. But one of the crazy ones I found was wild by William C. Shoulin, and the title of the patent is hair drying Attachment for clothes dryer. This this cannot be what I think it is. I mean, well, if you think it's you're putting your hair in a clothes dryer,

it's not. But if you think it's a tube connected to your clothes dryer that's used as a hair dryer, it totally is. It's a tube using the heat from the the dryer. I guess I guess you know it's good to conserve energy, and so if you're already creating that heat, you might as well, yeah, dryer your hair, even though even though you're mostly using steam at that point. Yeah. So the hair dryer, it's one of those where it's got like the whole thing that comes of the head,

the helmet. Yeah. I have no idea what those are called, and my hair days are long over. But anyway, it would fit over the person's head and uh and presumably dry it using the heat from the hair dryer. UM. I don't know how popular this invention was if it were ever actually uh, you know built, because just because something's patented doesn't mean that you're going to have real examples of it. But if you want to look this up, I got a treat for you. Here's the patent number.

You can put into a search, three million, sixty four thousand, three D sixty and you can look at the illustrations. Depending upon the patent search you put in, you may or may not need to use the commas in that number. You just could put in the digits three zero six four zero. It's entertaining, but obviously I can't really show it on an audio podcast at any rate. In um a vacuum chamber related dryer was proposed. Yeah, William Lambert Chanley filed a patent for a dryer that would use

a vacuum chamber. And this makes sense when you think about it in the sense that in a vacuum, it takes less heat to evaporate water. Yeah, so if you're able to create a partial vacuum. We're not talking like a complete vacuum, but if you were able to create a partial vacuum within a dryer, then you could induce wearing the pressure and yeah, you don't have to heat up the air as much, so you don't have to pour as much energy in it. As we'll talk about a little bit later, it takes a lot of energy

to power a dryer. In fact, it's one of the most energy hungry appliances that typical house has, so this will be a way of reducing that. Also, Channeling maintained that the high quote unquote roasting temperatures of clothes dryers and the fast rotation of the drum meant that clothing was being damaged and turned into lent, and that his invention would appeal to people who wanted to get a more gentle drying of their clothing, it wouldn't require as

much rigor. Now this particular approach has been experimented with a few times, but it's tough to make a chamber that is a partial vacuum, particularly if you need to have an exhaust to the outside to get rid of steam. Then you can't really make a vacuum without crazy valves and then having a venting time as well as a vacuum time, and and and and more energy being put in even than a regular dryer. Yeah, you can't. You beviously, can't keep introducing hot air into such a thing because

then you wouldn't have a vacuum. So it's it's one of those that was an interesting idea, but no one i think, has really found a way of implementing it where it really made sense. Plus it it makes it you know, it's hard to make a partial vacuum. It means they would make it more expensive. Yeah, they are working. NASA is funding someone to work on something related to that. But I'll talk about that way at the end of

the podcast. Excellent, there's a little teaser for you. So in the nineteen seventies, again going back to our friends at the Bureau of Labor, statistics while they're not talking to the patent office. The price of a dryer was closer to a hundred ninety dollars, which in today's money is closer to a grand, so half the expense of what it was in the nineties. Yeah, and about forty pc of all households had one. Okay, So when we get up to nineteen seven, the unit price is about

three hundred forty dollars. So remember it was a hundred ninety dollars in nineteen seventies, three forty ninety seven, and you think, oh, what the heck the price went up. It didn't go down, well, except that when you adjust for inflation from seven, it's still pretty close to three dollars. So the value has of that money has increased, the buying power has increased um for that amount for three so you don't so it's actually cheaper in the long run.

UM and of households owned a dryer by this time. That same year, over in Europe, a manufacturer called Electrolux would develop an energy efficient type of machine, the heat pump or hydraulic dryer. Over the next couple of years UM they gain market share kind of slowly but surely over in Europe and also in Australia, although they have not caught on yet in the United States. UM. More on how those work later on, but but they're pretty cool. They use some like forty of the amount of energy

that traditional dryers do, so that's that's pretty awesome. Yeah, and now we're getting up to just about today, right yeah. Okay, So so every year Energy Star, which is a program within the e p A, the the US Environmental Protection Agency UM, they announced an area of technology that's deserving of what they call an Emerging Technology Award, and in

it was advanced clothes dryers UM, which makes sense. According to Consumer reports, dryer's account for some six percent of US home energy use, which accounts for for three or more per year, which is think about this. You aren't running your dryer constantly. You run your dryer occasionally when you have to do laundry, and you don't necessarily have to do laundry every single day. So if you're talking about an appliance that you only use occasionally and it

makes up six percent of your energy, that's that's incredible. Yeah. Yeah, it means that you know, really small innovations could make for pretty huge savings and in terms of both money

and you know, overall carbon footprints. Um. So. So the e P A specifically or energy Star I guess I should say specifically called out a Samsung model uh named Cleverly DV for rolls off the tongue it does um uh that it estimates could save enough energy to run and AF clothing washer for eleven months um and also has an integrated smart system for monitoring your clothes remotely via app Yo dog, your shirt is dry? Uh? Well,

I mean, I mean you're you're you're joking. But there are sensors in these new kinds of dryers that will test moisture in your clothing. They can shut off automatically when your clothes are dry. That that was one of the one of the specific considerations for this award. It had to the dryers they were looking at had to contain at least two types of sensors for determining when your clothes are dry. And just that that way you

cut off the cycle. Yeah, you don't have it continuing for some predetermined amount of time when the clothes are already dry. There's no need to keep it going. I mean, you're just wasting energy. And shrinking clothes unless you're strapped for entertainment, and that's just you know, you're just sitting there watching the clothes tumble, in which case, HI, dr horrible. You know, I thought I had said it on delicates.

Turns out I said on bulky. But let's be fair, the pandemic means I really put on a lot of pounds, So it's probably more appropriate for me to be on the bulky setting while I process this. Let's take a quick break. We'll be right back. Okay, So now we're back. Radiss specifically dig into how dryers work, and we've kind of mentioned a lot of the elements already. You've got a typical clothes dryer, so we're talking about just your basic model that, yeah, most of mostly in the United States,

is the type you're going to run into. UM has a rotating tumbler. So that's your drum that rotates around and around and the clothes tumble within it. You've got some kind of heating element to heat air, which is then somehow drawn through that tumbler, right, So you probably have holes in the tumbler to allow air to pass through, and then you've got an exhaust pipe of some sort, so you can vent out that the warm humid air. Yeah, because no, you don't want to keep the steam in there.

It's just gonna make the clothes take even longer to dry. So by venting it out and constantly replacing it with dry, warm air, you're gonna end up, you know, drying a much faster. You just vent out all the steam. So let's start talking about all these various elements and how they work together. Let's start with the fan. Yeah, yeah, let's start. Let's start at the end. Yeah, the end, because the end is the beginning. The beginning is the end. It is the alpha and the omega of it's a

flat circle, yeah it is. We didn't mean to get all philosophical, but it is pretty late on a Thursday afternoon, guys, and things get weird. So the fan is located at the exhaust end of the dryer. It's not at the very front of the dryer. It's at the very end of it. But it ends up when it turns pulling air in from the dryer and exhausting it out the exhaust vent. That's the direction of air flow, so it's not blowing air in, it's essentially pulling air out of it.

So that means you kind of have some place where air to come into the dryer or else it is trying to create a vacuum, right, which is less of that's less effective. Yeah, if you just have a heating element and you create a vacuum, then you've got a hot spot in your in your dryer and no air

inside the tumbler, and that's not going to help. So these dryers have vents or holes that are in them that allow air to pass into the actual dryer and and be pulled in, Yeah, pulled in and then passed over a heating element, which, as we mentioned before, is either powered by gas or electric power. So this heating element, um, we'll talk about that in just a second, but that's what's creating the increase in temperature in the air, which will then, once it is warm, continue into the tumbler

where the clothes are. Yeah. I mean, if you've loaded your dryer correctly where the clothes should be exactly. If the clothes are not in there, you've done something very wrong. And we've made some assumptions and we apologize, but no, you put the clothes in the tumbler, that's where the warm air goes into next, it passes into the door area. That's where the length screen is. The air, not the clothes. Yes, the air, Yes, flows are passing through the door area.

You have not replaced the lent screen, and you should do that so they The lent screen is there obviously to capture lent from clothing so it doesn't end up clogging up the rest of the system. But that's where the airflow goes to next. So it's coming in through these venting areas, into the tumbler, out through the door

venting area. Pulled passes through the fan because that the next stop is where the fan is, and then the fan blows it out the exhaust area, which usually you have some sort of weird that that tubing stuff, you know, the tubing stuff that you can cut in half and then you can have robot arms. My cosplay is different from your cosplay that is accurate. I have a video that proves that. So that's your basic airflow, and that is the secret to drying the clothes is that introducing

this dry warm air, possibly dry hot air. It all depends upon the mode you've set it on. We'll talk about that in a second. Certainly Okay, so let's talk about how it gets warm or hot? What is this heating element? Like? Okay, have you ever seen a toaster like just regular toast a toast and you know when you when you mean, we're not talking about cylons, right, No? No, I mean no, because I've seen those two. We don't want to talk about the cylons because they might show up. No,

we're talking about toaster toaster. So we're talking about you know, you put a put a piece of bread in a toaster and you set it down, then you see those little wires turn red hot. That's essentially what we're talking about. Same sort of heating element. It's about of nichrome wire. Okay, so what you're doing is you're passing a current through this wire. The wire has a resistance to current. Resistance

means that quite a lot of resistance. Actually yeah. Um, it's sort of the opposite of what you want to do in any kind of electronic wire technology, where you're trying to insulate it so much that that it has as low of a resistance as possible. Right. Yeah, when with low resistance you make it really really efficient, right, you're not losing energy to heat. But in this case, what you want to do is generate heat, is lose as much energy to heat as possible, because that's the

kind of energy one is the heat energy. You're not interested in passing electricity on to some other points. So in this case, this electricity gets converted into heat due to that electrical resistance. And this is the element of the dryer that consumes the most power that the rotating drum not even close, the fan not even close. It's this heating element. So a typical dryer is pulling in like four thousand to six thousand watts. That's a lot. Yeah.

Now we've got the tumbler. Uh, it's it's a really simple pulley system. Actually, yeah, you know, you got a motor, the motor, electric motor or gas powered motor. A belt attaches from the motor to the tumbler yep, and the motor turns. That ends up turning the belt, which ends up turning the tumbler. It's pretty it's one of the simplest machines ever. Actually, the pulley system. So yeah, usually you have to have maybe you know, two pulleys that

are involved. One is creating tension on the other so that it stays in place, because obviously, like if it slips a belt, that's when you're starting to get this weird noise and your dryer is not gonna be turning properly, and then you need to shut things down before your motor burns out. But assuming everything's working fine, it's just gonna turn the tumbler. Next. We have the controls. So

we have two different types of controls. Right, the modern dryers you would buy in an appliance store today, most of them have digital controls, which involves having a micro controller. But if you're going with an old dryer, let's say like the kind of dryer I grew up with, where

it had like a dial and buttons and a little button. Yeah, you punch the button saying okay, I'm going to do permanent press, and you push the permanent press button and it and it clicks in, and then you would turn the dial to the right setting, and then uh, it would be possessed and start rumbling. And that's because there would be a series of of gears and cams. So and it worked a little bit like a like an

egg timer. Yeah, yeah, kind of. Yeah, you have like a you have a physical capacity that that when it ran out, it would it would cause a shot off valve, a shot off circuit disconnect. Because with a CAM you can think of it as like think of it like a metal key, and when the metal key makes contact with a contact point, it completes a circuit. Right, So when the circuits complete, electricity can flow. And then as long as that that key is making contact with the

contact point, it'll stay in place. The electricity will continue to flow. But at the timer, when the timer comes out, a mechanical piece will push the key out the way, breaking the circuit and thus the dryer. Yeah, so we're talking about programming something through actual physical moving pieces, mechanical pieces. But it's it's doing the same sort of stuff that digital controller is doing digitally, it's just doing it all mechanically and with electronic pieces. So yeah, it's kind of

exciting stuff. Like if you ever were to take one of these apart, first of all, I hope you don't need it afterward, because if you do anything, you know, if you're anything like us, you're not going to get that back together. No. No, we might be able to put something back together, but it ain't gonna work. Let's just put it that way. Really interesting though. Yeah, so you can actually see that they are all these little moving parts that need to come into play so that

they touch these contact points and create these circuits. They also usually have In fact, as far as I know, dryers are required to have temperature shut off switches. And these aren't to measure the temperature of your clothing, but the the temperature of the overall unit, so that if it gets too warm, um, and is in danger of melting down the motor or any of the other operative parts or causing a fire. Causing a fire, you can shut down. Yeah, It'll just break that contact and you

will lose the circuit and thus the dryer will shut down. Um. So you know, it's kind of a fail safe there. And uh, some of them, like we said, have the humidity sensors, so they can actually measure how much humidity is within the dryer and if it reaches below a certain threshold, then the dryer will shut off because your clothes are dry, so that doesn't have to continue to operate and thus consume more energy. Now, there are other

types of clothes dryers out there. That's the basic type, that's the one that's the most common in the United States, But like you were saying, Lauren, it's not the only kind out there. One of them is called a condensing clothes dryer. So these don't have a vent to exhaust steam. They don't have that fan pulling the air through inventing

it out. Instead, these dryers allow water to condense and then collect, either draining into a collection pan or tank, or more likely draining into the house water waste system. So if you have a washer dryer combo, something that can act as both a washer and a dryer, it's usually this type of dryer. It's a condenser dryer more often than not. Uh, And so putting an exhaust on a washer that would be really not good. Yeah, I

mean you've got like the wastewater exhaust. But if you had just a pipe that was supposed to allow air to go through, water would go through that too, Yeah yeah, which would make it an inefficient washer. So yeah, then you have the heat pump dryers, like you were saying, yeah, yeah, these these have a These have just just a normal old heat pump. I mean, I mean the kind of thing that we were talking about in in in our refrigerator episode. Yeah, yeah, yeah, it's a heat exchanger, you've

got a hot side and a cold side. So the cold side is really important because you've got that hot, steamy air. And when you have hot steamy air meat a cold service, that's when you have water condensing, and then that condensed water can then flow into a pan or a drain, just like in the condenser style. The warm side of the heat pomp can reheat the air

inside the dryer. So as the dryer air is losing energy because it's encountering that wet water and causing it to evaporate, that means that the air temperature starts to go down, but this heat pomp continues that cycle, so the cold side is removing the water, the hot side is increasing the temperature, so you can have a more

efficient means of drying out the clothes inside. So again, no need to exhaust unless which is great because if you don't have to exhaust this thing, like by exhaust, I mean you don't have to have a pipe where the exhaust air flows through. There's no need for that in this model, and that's great because when you have an exhaust pipe that's open to the environment, that means that you're losing some of the heat that you want

to put inside the clothes just going out the exhaust pipe. Sure. Sure, and you're you're losing through that exhaust pipe that heat out into your house. A switch, for example, during the summer months can make you run your A cmore more intensely. Yeah. So, uh, it's kind of a domino effect, right, So then we can talk a little bit about these future dryers. One

of the which one of the ones that you mentioned. So, first of all, there was an idea back in the nineteen sixties to try and use microwaves as a as a means of drying clothes. So you would make a special dryer that be a microwave dryer. Supposedly there are some of these in Japan, but I've never seen like an actual source source about it. But the real problem with this is arking. So arking is when you get

these little plasma forms. If you've ever accidentally put something metal in a microwave, and here's where I tell you, do not put metal in a mica on purpose. Now that's very bad. But if you've ever accidentally done it, then you might have seen arching where you see these little plasmat lightning bolts. Yeah, or if you've ever had one of those plasma balls where you put your fingers on it, it's kind of like that too. In fact, it is like that exactly. What's what's happening. Um, it's

not good for your microwave in general. I used to have a microwave that had a special stand that came with the microwave. Okay, that was meant for popcorn. Like you put a bag of microwave popcorn on it, and it would elevate the popcorn so that it would have more uniform heating. Despite the fact that this came with the microwave, which I would assume means it's safe to

put in the microwave, it would occasionally mark. Not all the time, but sometimes you would get a mark, and I would think, I do not want micro microwave popcorn that badly. Yeah, that's vaguely terrified. Yeah. So anyway, if you were to put stuff that's like if you had metal stuff in your clothes, either like change or or yeah, or buttons or other clasps things that are metal, then that could possibly cause this arcing problem which could damage clothing.

And in fact, that's the main reason we haven't really seen it implemented. There have been other people who have tested it, and there's still people who are thinking that there might be a way of doing this in a in a in a manner that's not going to make your clothes burn up right right, which is really the per us of me drying my clothes. I don't know

about everybody else. There are occasionally shirts where I'm like, no, never mind, we'll see step one for me, as I want to get my clothes dry, but step two is I do not want to burn holes in them. Yes, but okay, So as unlikely as it sounds that this could be a really viable plan. This, this is the kind of system that that NASA has granted some some money too. They granted one company specifically called Umqua all in capital letters because why not, it's spelled exactly the

way it sounds. They granted them some funding through their Small Business Innovative Research Program back in twleven, and um that the system that MUA is working on the last time I checked, involves ceiling clothes in in a vacuum bag and um cleaning them by jetting water and soap through the bag and then drying them via microwave radiation. And then furthermore making them all soft and cuddly with jets of air. Interesting, so you've got a whole bunch of things in there that are are similar to a

pro ches that were considered. Yeah, so maybe this could be a terrific failure in space space. In space, nobody can clean your underwear. It's a problem. I mean yeah, I mean, I mean you're in microgravity. I mean you either you either have to bring infinite changes of underpants with you, right, which, try and get that through customs, right right, I mean, and it's really expensive to bring stuff into space. You don't want to do that. I mean you you want to be able to wash him.

Everyone wants clean underwear. Yeah, no, that is very and if you don't, you should. Okay, we're not judging, We're just I'm judging. Okay, we're judging a little. That wraps up this classic episode of tech Stuff how closed dryers work. I hope you found it interesting. If you have suggestions for topics I should cover in future episodes of tech stuff, let me know. Reach out to me on Twitter the handle we use as tech stuff h s W and I'll talk to you again really soon. Text stuff is

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