It looks to me like the 'inspection port' might be for filling the unit. I noticed a white dot in the center - can this be pressed in - I imagine it might be a one-way valve, and pressing it might open it to the air allowing the gas built-up to escape.

Because it makes a boiling sound I'm going to suspect its a metal heating element mounted on the same side as the plug port. As the unit puffs up it no longer submerges the element and its temp spikes up and triggers the thermal cut out. I would also start to think that there is some kind of contaminate going on like bacteria causing gasses to rise. my first instinct is to vent out the "air" in it and add something like a few drops of vinegar to it and then cap it and see how well it works then.

Many decades ago my mother had a Carmen branded heated hair roller kit. The rollers were stored on a plastic lidded box, each roller on an individual metal pin, and those pins would heat the rollers that you then curled into your hair and waited for some time for the hair to assume the curled shape. I seem to remember that mom sometimes complained that the rollers got a bit too hot for comfortable handling, and I think each roller had a color-changing dot to indicate when it was hot enough :)

The swelling could be from gas production if there are cheap immersed electrodes instead of a proper coil doing the heating. Perhaps hydrogen gas has been forming due to hydrolysis. Perhaps the bag that holds the liquid or gel has shrunk with repeated heating. Obviously the amount of liquid inside can’t change since it’s a sealed system.

I have a similar device and on the manual it mentions that the puffing will occur after some time. When that happens, it recommends to open the screw and relief the pressure.

there's a version of this where you add your own water , it comes with a tiny funnel which screws on to a standard sized water \soda\pop bottle and you remove a tiny rubber bung and squirt the water in and replace the bung 😊

That ‘inspection’ port looks like it’s a bung, try prying at it when outside or over a bowl. It may be sealed to the bag though.

I've never seen these before, pretty neat. Have you measured the element with an Ohm meter ? I would love to see a tear down.

Maybe the inspection port is a pressure relief valve ? You assume the 3rd pin is earth, but maybe it's some sort of signal wire for temperature, take the charger apart to see where the wires go, or a continuity test If the bottle is too puffed to be sensible to use, maybe wait for a slightly warmer day and take it outside, override the microswitch and see what happens, will the potential valve leak, will it explode, will the thermals cut it off

It contains salt water and the AC is directly fed into water via electrode.

Would love to see the hidden secrets of it, Julien

I would have hoped there would be a PTC element in there. But the fact that it has two further lines of defence makes me wonder.

Happiness is a nice warm muff

It makes you wonder why they don't just put a degassing port of some sort on the "bag"; by the same token, they have to get "the liquid" into the bag somehow, could you use a syringe needle to open such fill port open again to allow some of the gas out?

I'd drill a 1mm hole next to the port to let the gas out and then re seal it with epoxy. That should get you a few more years and not interfere with the safety valve, if thats what it is.

I think the gel must outgas as it ages. All the microwave bottles we've had have gone puffy over time, even if never overheated. A pin puncture and tape keeps them going. 😁

The best ones I've found recently (and most safe) are issolated power supplies at 12V DC. Then the wires are far less risky and there is no water, just a generic gel to disfuse the heat from the entire length of the wires.

This is crying out for a look with your thermal imaging camera. You might be able to see what the heating element looks like.

Funnily enough I suggested to a friend this week that she needed a heated muff. Took several minutes for everyone who was with us to stop laughing.

Is the pressure build up not simply due to the creation of water vapour as the water in contact with the heating element boils. I'm not saying the whole thing gets to boiling but just the water in close contact with the element.

I remember codyslab talking about how wax is much more suitable for a hot water bottle compared to water, because it goes through a phase change while cooling off and therefore stores more heat energy. So maybe the Fluid is some kind of paraphine oil/wax mixture?

Have you left it over night in the refrigerator or freezer to see if extra cold will condense some of the excess gas? Other than that, try to burp it via the "inspection" port, or tear it down.

That "inspection port" is probably a pressure valve, weakest point of the bag, so will not explodes when something goes wrong in a closed loop system like that.

Awaiting the lit match / hydrogen build-up test. Takes the dangers of smoking in bed to a whole new level.

With the connector loose from the bottle, install the charge cable without fear of it being pushed open and lets see if the cutouts work first or if the bottle opens up. Then, dissect it. With the ground going inside the bottle I would predict a proper heating element. Who knows.

I actually cut mine open to see how it works this evening. Discovered there is a " bung " to add water. ( not sure whether its at point of manufacture or later ) Read an obscure post where a chinese man said let the air out & it will work properly again . I had to dissect it to find how to let any air out. Removed some screws around the housing and near the plug-in bit is a rubber bung held in place with a covering with screws. Too late, it was disemboweld, to try top it up, but I'll try with the next one i buy. Little kettle type element inside. The water had something in it because my skin started tingling, so i washed them quickly. The product design has zero thoughts about the environment, and it is definitely not made to last.

It will be interesting to know what the resistance of the heating element is.

I think your "inspection port" might be what they used to fill the water bottle with whatever liquid is in them

My 8 year old hot water bottles still work perfectly. I just fill them with hot water. 😁

Strange thing is the third terminal is not an earth?? but conection to the LED

That little window might be a fill port. If you jam an xacto under it the cap might come off. I would definitely be interested in an autopsy.

You think that carbon rods in the ruuber balloon is horrific, just imagine them shower water heaters that just pass water over mains electric. See one in indonesia and I was instantly thankful I am only 5 foot 7 inches tall, any taller and you might start to feel the tingling of the electric coming out.

I like the way it turns itself off.

What's with the specs of the container for these? it indicated 220v 360w, but on the same line it says input DC 3v 300mA 3W, it seems like they've just pulled numbers out their butts for the packaging. Even the lower figures don't add up, 3v@ 300mA is .9watt, not 3 watt.

Press the white button- it must be a valve of some sort!

Do a teardown!! Please!

Q: "I think this is called a muff isn't it?" A: Not in America...

well when i've been worked too hard i get hot and puffy.

"If this video turns a profit"... Really? How much did it cost you to make and upload this? Won't one one-thousandth of a cent revenue be a gross profit over your expenses?

Hydrogen, oxygen and electricity, what could possibly go wrong?

RKW are a massive electrical wholesaler in Stoke, not Stevenage - they also include the TOWER brand amongst their brands sold. Looking at their reviews, I hope nothing goes wrong with your bottle...

I noticed recently you mentioning "if this video turns a profit" in a few videos recently, and that makes me wonder, are you only considering the youtube ad money and not counting sponsorship money for some reason, and if that's the case, I don't get it, and if the only revenue you get is from adsense on youtube, and if that's the case, it makes me wonder why are you giving JLCPCB free advertisement.

If you don't cut it open and look then you'll never know what's actually inside. I don't know if I'd keep using the swollen one anyway IMHO.

4:23 Putting your hands in the muff section. Hmmm...

Why not disconnect the switch in the base/charger unit? And also try let the gas out through the filling port.

If that thermal switch is 92 C I don't want it touching any part of my body!

can you use a bucket or a large earthenware jug that can hold the liquid.

Bummer, i've expected a full opening of this "bottle".

1:30 Julian just gave us a finger ;-D

That puffy one... I kind of want to poke it :D

Any idea how to stop them from over inflating ?

I would just make a tea and hold it to make my hand hot, but if people like to spend money on such thing I will not judge 😉

Mate of mine is the IT Manager for RKW in Stoke

Puffed up muffs ................ school boy giggles 🤣🤣

Cut the puffed one. We have to know what's inside 😅

Well Julian your going to busy on Telegram by the look of the comments. When will i expect to see my blow up water bottle with real fur that i ordered just now. 🙂

Any interest to review our monitor?

Possibly a couple of resistive mica sheets? Project Farm tore apart some heated gloves and found something similar in one pair kzfaq.info/get/bejne/l657o5x027rFmps.html

Get your knife out, Julian. Or, turn that inspection port into a bleed port so you can keep using it.

Julian has now moved on to the vid-tease-bait style of production. TEAR THE THING OPEN -- you've got loads of 'em!! lol

I believe it's a muffler. A muff has only one place to put your hand.

Wouldn't infrared camera reveal the heating element shape?

ST is Stoke, Stevenage is SG

my old rubber bottle is shedding black bits when i pour the cold water out, so i think i'm starting to play bottle roulette every night. well if we wake up and the beds got wet and warm i can blame the bottle. #;-)

Yes cut it open, for not to do so would be a sin, we need to know what's contained within.😏

Sodium Polyacrylate in the water??

Surely you will have to cut it! :D In the name of science!

I'll be honest i felt stupid watching this video. its obvious that it a plug to shut the hole to refill the water. there no complicated technology involved. It is a simple two electrode in salt water mechanism to warm the water. after a while you just have to replace the water as it gets contaminated with electrode material mixing with the salt water.

That title . . . Click bait? I do like your channel but please don't tease.

Teardown teardown teardown.....

Muff!

whats wrong with an old fashioned hot water bottle? They cost like a fiver.

Do it!!!

Gut it like a fish !!!!!! VOCODER !!

I am suprised you didn't link Clives tear down and also you could see the filler on yours when you removed the plastic kzfaq.info/get/bejne/o6pndrummMfaeYU.html

Just hot wire it.

WhatsApp scammers in the comments

Can you help me i need help in build a mod. What's the best way to contact you if you are interested?

It’s Amazon… not Amazin…