I was going to return to that toilet in Beckenham with a ladder and a high vis jacket so I could show you the syphon inside the cistern, but I chickened out. So you'll have to do it yourself. Bonus points if you can find that exact public toilet. The sponsor is Henson Shaving: click this link www.hensonshaving.com/stevemould and use the code stevemould to receive 100 free blades with the purchase of your AL13 razor.
hey! in canada (and the us) it`s the same type of system, although we`ve mostly done away with communal urinals, in favor of individual ones, and they all flush on their own time. actually now, they have infrared sensor and they only flush when you leave the urinal. but older ones have that same system as you describe.
I've seen those sort of urinals in dive bars (where it's do or die time, and anything will do the job. Ugh.). The... scenery is universal. Where you wish you could float an inch or 2 off the floor, because you *swear* your shoes are dissolving. You probably don't want to climb anywhere *near* that cistern- otherwise, we'll get a heck of a special on disease transmission...
As a computer programmer, I always love seeing these complex mechanical designs that do complex stages of things using nothing but simple physics. The thought process it takes to create something like this fascinates me.
Even more insane: This same sort of complex staged exploitation of physics plays out at a microscopic scale inside of a computer. It's just the flow of electricity rather than water. As a programmer it's wild to think about the absurdly complex process that is set off by high level code. What's actually happening inside the CPU billions of times per second. I'm always impressed by mechanical designs that don't rely on a computer, by the elegance of the engineering. Then I remember that that's also true of a CPU, the parts might not move around but it's the same cascade of interconnected simple components. Freaking wild.
Here’s a tip for understanding the different layers of chambers: Instead of using a white background with blue water, try using a yellow background. This way, as the blue water fills up the chamber, you’ll see green water, making it easier to visualize the layers how the water is filling it up.
Every video since the gas station pump thing has only increased my respect for the people who can work out these systems that are simultaneously simple and complex.
its iterative. they didnt start with nothing and then suddenly produce this, they had basic systems that they combine and build upon to achieve these results.
The combination of chill vibes elevator music and 80s adult entertainment soundtrack to the imagery of a urinal flushing mechanism at different speeds is absolutely on point Mr mould 👍.
I like the fact that no physical valves, springs, flappers etc are needed for it to work. Therefore, in theory, it should last for a very long time with little to no maintenance.
Yeah, same. That's also probably why the bathroom shown in this video is so poorly maintained 😂 Whoever thought of the fact the water itself could be a valve to block air from exiting is a genius, then executing it is even more impressive.
The only time I see these communal flushers is at urinal troughs, which used to be more common. Sometimes you still see them in stadiums. The last time I used a trough was at First Ave in Minneapolis, though I'm not sure if it has a common flusher.
My highschool had urinals that all flushed together periodically. I don't think it used a siphon though, it had a motion detector so it wouldn't flush if noone had been in the bathroom recently.
Thanks so much for this video. There's a whole community of gardeners using plain bell siphons in aquaponics who have trouble getting the siphon to trigger. Your clear explanation and visual of the system will help design better siphons and reduce these problems. Great stuff, thanks again!
I grew up in the UK, in greenham common. From there I could see a manor house. We visited the Manor House a couple of times, and one time my mom and sister walked into the bathroom and reported that the toilets were flushing automatically all at once. I didn't know what that meant, and I suspected that there was some mechanism besides the roaming ghost that my mother had reported, and now 50 years later, you've given me the answer. Thank you Steve
Only problem with that is they normally only put urinals with common flush mechanism into male toilets... I wonder if the toilets had a similar system? (But what if someone did no. 2 and wanted to flush it immediately?)
Whoever came with that invention was really clever, a valve and a timer with no moving parts, "very impressive". As a side note i appreciate the mrmattandmrchay channel for old elevators videos, they are fascinating in their own way.
I have definitely seen them in (Canadian) public schools back when I was young. That constant sound of water trickling... They've clearly been replaced by those electronic sensor/eye things en masse to conserve water as they were flushing all night / weekend / summer when no one is around.
I haven't seen one like that since I was a kid at a beach campground bath house, I'm 32 now, I think I was 9 years old on the camping trip I'm thinking of.
I was searching the comments trying to figure out why his hands were blue. Took until I found yours to realize it was probably from the dyes he was using for the water demonstration.
I appreciate that you show your mistakes. Sometimes I feel stupid when I don’t get these setups right away. That’s why I tell myself - this isn’t as simple as you’re able to make it out to be lol
Technically, you should have kept pouring once the siphon initiated, to show that it works even if water keeps trickling into the reservoir (as it does in an actual installation).
Related, in the aquarium hobby there are overflows that the hobbyists want to keep quiet. But the shapes tend to make siphons, so there is work to do the opposite … keep the draining process quiet by encapsulating it, but engineering it so a siphon doesn’t form. “Durso standpipe” is one such design.
Reminds me of a transistor driving another transistor called a Darlington Pair. This allows a really small/weak signal to drive a big load. Well done Steve!
@62Cristoforo no, a relay refers to an electromechanical device where a small electromagnet closes/opens a switch. It does serve the purpose you stated, however there are other ways to control a large curent/voltage that don't require relays.
This finally answers any question I had about how adding water to a urinal leads to this flushing action where the water disappears for a second and then comes back. Truly amazing!
If you pour too much wine into Socrates' cup, it automatically dispenses urine into his fabric conditioner rinse cycle, ruining his togas. Full success!
That’s way too complicated for me to follow which is more a reflection of me. I love the craft and dedication to something that seems on the surface to be so esoteric. Beautiful physical illustration of physics with the two shades of blue. Youz wunna ‘em smaat kids. Bought a razor too. Thanks Steve :)
That bathroom is definitely the single most terrifying thing I’ve seen on RUclips! I have a phobia of public restrooms and I rather spend a week in Aokigahara Forest with no flashlight than 10 minutes in that bathroom. Especially when the flush happens by itself! 😱
That transition was almost as smooth as the siphon action! 😄I've used Henson for about 2 years now and will never look back. I don't even use shaving cream--just right out of the shower, zip, zip.
Automatic mechanical systems are so much more reliable and cheaper than ones based on electronic controls which invariably give trouble with corrosion of contacts, broken wires and batteries that have to be replaced. E.g. stairs vs lifts/escalators, ball governors vs electronic speed control systems, carburettors vs engine management control boxes, self-steering vanes vs autopilots (for yachts) etc. Thank goodness (Thomas Crapper) for the flush toilet and thank you for the efforts in making this very interesting video!
I worked on autosiphons for ebb&flow beds in hydroponics/aquaponics. They're really fun and once you get them dialled in they are very low maintenance, because there are no moving parts. But indeed matching the sizing to the required outflow and minimum inflow can be a pain. Very interesting to see how they solved that with this multi stage siphon setup!
I like how you show all your "mistakes", because they made you get a greater deapth understanding of how it works (and doesn't) and that feeds into the video. I still think a few more arrows and a more detailed explanation of what happens at the moment of "flip" occurs would be a big improvement. Reminds me of when I worked out how a proportional brake valve with loads of chambers worked many years ago. Nevertheless I still struggled and had to do a good number of replays before I got this.
I am not convinced the blades (sponsor of the video) are working well - based on the look of Steve's beard at 12:42. Maybe if you show us how well they work ;)
I think I've maybe seen one urinal like this in the US, it was at a fair ground and was very old. Every other urinal I've encountered has its own individual flush. I assume this is so you only use water when someone has actually used it, rather than flushing it regularly regardless of how often it's used. The siphon systems seems like it would be pretty wasteful if that bathroom isn't very busy, and like it might be insufficient to prevent the place from starting to stink if it's being used heavily. It does have the advantage of being automatic, so someone can't just forget to flush. That's typically solved electronically with a motion sensor these days, but I can certainly see why someone would have wanted something automatic long before electronic sensors became possible or practical.
I wonder how hard it would be to make an entirely passive rainwater flushing system out of stone or concrete or something... can you imagine? Build the thing one day and for the next 100 years, barring drought, it's just flushing every 20 minutes or whatever. I suppose it'd be pretty hard to keep up a 20 minute flush cycle with just rainwater, but the idea of completely passive flushing is intriguing to me.
@@reaganharder1480 Seems very doable mechanically. But rain water is so dirty, I would be worried about the whole thing being clogged up with grime and algae pretty quickly.
I can't speak for other parts of Australia, however when I had a plumbing business in Sydney with my brother we installed heaps of these in schools in the 1990s. We converted quite a few of the old pull chain, overhead, urinal cisterns to siphonage cisterns.The big advantage is no moving parts, (in the cistern) so minimal maintenance. To minimise water wasteage they were always connected to the mains supply via a check valve and an electrically operated solenoid valve with a ceiling mounted motion sensor so the cisterns would only fill and empty when it detected someone at the urinal and not while students were in class for extended periods. That toilet you filmed in is cleaner than some of the ones I've worked in.
I am in awe at your curiosity about tricky physical phenomena and ability to set up experiments for them. I am really impressed at the frequency with which you upload videos, *each of which* is about an unusual or counterintuitive aspect of physics AND has beautifully filmed experiments for it. Awesome job!!
I don't have anything interesting to say besides thank you Steve, for being a great teacher and a role model for an aspiring teacher. This is a mechanism that wouldn't be possible to approach understanding in 10 minutes ever before (without a very good plumber on hand anyway), I reckon. It was very satisfying to see this maze of pipes turn into areas of pressure and flow in my mind.
I saw one such urinal in Slovakia. It was used to very recent day. But the flushing did not work (probably for ages). When I tried t enter through the door, it was like there was invisible barrier and I could not physically pass. The smell was that strong.
They are all like that. And their jacked up teeth. And they are still shitting in the sain. The Olympians with feces by the liter in their guts. They all stated that the water was in fact, not cleaned up. Over a billion spent and literal turds still afloat. Unreal filth. USA, I guess.
This is pretty cool I've been using a similar design in my aquaponics for a while and didn't even realize it. I built a bell syphon and made some modifications and I just realized, I somehow made exactly the same thing you just demonstrated in this video. Wild I didn't even know this already existed would have made designing mine much easier.
While in Czechia back in May, I used these urinals several times in one of the buildings, and was flabbergasted that it seemed to “know” when to flush. I searched for sensors. I searched for a peephole, imagining a small elderly Czech man waiting for me to relieve myself to a level where flushing was necessary. I finally decided it HAD to be associated the the water level when urine was added, but didn’t know the exact mechanism. This is amazing.
The only urinal that I've encountered this at here in Canada was in some of the boys' rooms in my high school (built early 20th century). To save water they'd shut off the valve about an hour after classes ended and locked the door, so if you ever stayed for late activities you had fewer bathroom options.
I just discovered YOU. I'm a mechanical engineer (retired) and kept wondering WHO invented this. Did he (or she) get properly compensated? While I watched I also thought, "Wow, this is similar to the old Fluidic systems." Then at the end, I see you have a video about a water computer. I haven't watched it yet but I was taught control systems, which included fluidics just as digital computers put them out of business for most industries. While in college I worked construction jobs where the business buildings had fluidic HVAC systems. They definitely have some advantages. -- I'll be seeing you again. 😃
Like all good things, these mechanical devices have now been offshored to a team of low paid IT workers monitoring security cameras placed at each urinal. They use their expertise in remote desktop control to flush the urinal when one finishes using it. You can tell an operator is monitoring by the little red LED that lights up behind the smoke stained window in the control unit above the urinal.
I knew someone who worked at a remote toilet flush facility. Each worker had 2 screens and could connect to as many toilets as they could handle. The more experienced workers could take care of a busy rest stop by themselves, but the newer recruits had to take on less work. They were paid by flush, and if the person manually flushed the toilet they lost that pay for being too slow.
I am amazed at the number of people who dont even understand a simple siphon. Have used (manual operated) siphon all my life. Used to drain my moms swimming pool for winter (and during the winter as rain re-filled it). Loved being able to walk away and know when it got low enough it would shut off but it had no motor or moving parts and used no electricity.
"for handing around in men's toilets" LOL! At first I thought that was a Freudian slip, and you meant "hanging around", but then I googled "cottaging"!
I remember my dad's real ale festival cooling system. The barrels had cloth sheets over them with long pipes with small holes drilled in. Then a urinal system was used to pump a flow of water through the pipes on a regular basis keeping the cloths damp. It worked really well.
@@ArchangelExile I know it is a light-hearted banter reply, but no joke for a moment. If at any age, but more commonly above 50, you have dribbling problems, that may be a sign of something wrong with that gosh-darned prostate.
Canadian here. Never seen a urinal flush purely using physics. It either just goes down and empties like a normal drain (they're at waist height instead of being on the ground) or other times there's a sensor that will flush it with a surge of water when it detects a human is there, and when the human leaves, initiating a FLOOSH!
1:39 Don’t know about the rest of the world, but the US definitely doesn’t have that. In fact, we don’t have that kind of massive urinal; all of ours are individual units. The only thing I recall that comes close to it are these trough looking ones that are at my nearby renaissance fair, and I’m not even sure if it has a flushing mechanism at all or not. Edit: Actually, nevermind; thinking about it, I think my local fairgrounds has (or at least had) that communal urinal. Weird that they’re both at places with the word “fair” in them.
Petition to call the 2D version the "Nebraska Siphon". Reasons: The back side looks vaguely like the American state of Nebraska, Nebraska literally means "Flat Water", and also, there's just something goofy about naming something after a forgettable place.
I know some others mentioned this, but you gotta keep the water running while draining to reflect real world install. This also introduces another variable in the ratio between in and out flow and how tuning those two affects function. :) Also, you can fix your original, more simple, siphon by adding a 90 degree bend at the outlet with an outfeed pipe. Anything more than 90 degrees will introduce hydraulics, which will create inconsistency. And you say no moving parts, but a pump has to create pressure in the lines. Unless we’re talking about a rain fed, gravity pressured urinal. Sorry if this reads as critical… this video was just super interesting to me as I’ve puzzled over this exact problem with hydroponic gardening. Huge fan and love your videos!
That urinal design feels like whoever originally designed it was trying to make the experience of using it as close as possible to pissing on the wall in an alley outside the pub like it's 17th century London.
In Hong Kong, pretty much all the public toilets used that auto siphon. The school I went to also used those in the toilets. The ones inside more modern buildings have the IR sensor flushers, though. In contrast, I have not seen the auto siphon in Japan, only manual flushing or IR sensors. Ps: I think it is interesting to note that HK, a former colony of Britain, has very similar designs to those shown in the video, while Japan, which was not a colony, does not. It would be interesting to see if there is a correlation between being a former colony to the auto siphon usage in toilets.
If you're thinking of what I'm thinking of, I've seen these, in use in life science labs, even into the 2000s, and the lab I work in used to have one but never used it. They were meant for washing reusable glass pipettes, which is good from the standpoint of reducing plastic waste, but terrible from the amount of water they use, because they are nowhere near as sophisticated as shown in this video, so a fairly high input flow rate is required for them to work, which is a fair percentage of the exhaust rate, so a substantial portion of the water that goes through doesn't actually do any work cleaning the pipettes, and the top parts of them get much less soaking than the bottom parts.
@@Lucius_Chiaraviglio Ah, I know exactly what you mean but that's not what I was talking about. The ones I have are part of a jointed glassware set and are much smaller, made of glass and transparent. Bizarrely I can't find any photos of them on the internet, so they must be relatively rare. I imagine quite expensive too, as it's fairly intricate glassware.
@@JohnnyWednesday Well usually urinals have some kind of sensor that flushes them automatically when you leave. Isn’t this a huge waste of fresh water?
@@abc321meins - Oh I see what you mean - no this is Britain, the one thing we never lack is fresh water. It rains so much that we're immune to waterboarding.
I built one of these to make an old bath into a garden pond filter, it took a bit of tuning but it worked like a dream as a hydroponic system to filter my pond and grow various plants
I've often wondered how a toilet worked but never been quite curious enough to look it up. This is actually a lot more interesting than i thought. Very cool.
It's a compound syphon, you see these sometimes in the traps of condensing boilers to quickly remove waste water colllected from the flue that accumulates very slowly.
I have only seen US communal urinals at large parks and state fairgrounds, but I've never noticed the flushing mechanism. Very cool to watch it happen!
I use a straight edge razor for years now. Never clogs, never needs a new blade, doesn't matter how long it's been since the last shave. Just a few strokes on the strop and you're good to go. Yes, it takes a little time to get used to, but you'll never have a better shave than what can be achieved with a "cut throat" razor and some patience. The whole experience is quite "zen" too...
Great video as usual. Here's an idea for future near-2D models: make the required 3rd dimension using bypass hoses going in front of the system. For example, this system would have required one bypass hose and if you had connectors for such a bypass pointing towards the camera, you could have one transparent pipe going horizontal in front of the 2D model making the whole model practically visible at once, especially if the hose is positioned to avoid hiding any corners or connectors in pathways. You could probably use connectors meant for PC water cooling to attach hose to flat piece of acrylic and also use hoses meant of PC cooling. If you build things carefully enough, you can probably use hard tubing which should result in very clear image.
For all the women watching this who have never seen the inside of men's restroom: this system is used above a large trough because the men are too drunk to aim. I cannot speak to the rest of the world, but in the US it mainly exists in bars and some public event venues, most places have individual stalls.
Intrigued by the Henson razor sponsorship. You said that it took a while to adapt to it. Yet you have a full beard? Love your channel, but this made me smile. 😊
I think I can use some of these concepts to build an automatic system to water my carnivorous plants. I need it to trigger when the water level is low, and stop when it reaches the high level. Thanks for the inspiration!!
Steve, I absolutely love the Henson safety razor! I bought it in December last year and have changed to my second blade just recently. Great suggestion! Thank you for it!
Great video. I was planning to build a bell siphon for dumping condensation periodically, but with the slow accumulation makes that not work for the reasons you mention here. Thx for this!
Haha, the blue stained hands show the dedication 👏. Your demonstrations of these “fluid dynamics”* always remind me of microfluidics. I would love if you made a video about them and attempt to make scaled up versions!!! Not sure if it could be scaled up due to the difference, but your explanations and exploration would be fun and interesting to watch nonetheless!!! Cheers!
Yankee here. I’ve never seen this in my life. Our urinals, basically without exception, are individual units with individual flushing mechanisms operated either by lever or by proximity sensor.
I was going to return to that toilet in Beckenham with a ladder and a high vis jacket so I could show you the syphon inside the cistern, but I chickened out. So you'll have to do it yourself. Bonus points if you can find that exact public toilet.
The sponsor is Henson Shaving: click this link www.hensonshaving.com/stevemould and use the
code stevemould to receive 100 free blades with the purchase of your AL13 razor.
Epiko
hey! in canada (and the us) it`s the same type of system, although we`ve mostly done away with communal urinals, in favor of individual ones, and they all flush on their own time. actually now, they have infrared sensor and they only flush when you leave the urinal. but older ones have that same system as you describe.
What if you want it to drain once a day, like watering plants while you are away?
I've seen those sort of urinals in dive bars (where it's do or die time, and anything will do the job. Ugh.). The... scenery is universal.
Where you wish you could float an inch or 2 off the floor, because you *swear* your shoes are dissolving.
You probably don't want to climb anywhere *near* that cistern- otherwise, we'll get a heck of a special on disease transmission...
Then, you do the calculations to make the system empty once a day, using proper sized pipes and tank. A little trial and error might also be involved.
As a computer programmer, I always love seeing these complex mechanical designs that do complex stages of things using nothing but simple physics. The thought process it takes to create something like this fascinates me.
Even more insane: This same sort of complex staged exploitation of physics plays out at a microscopic scale inside of a computer. It's just the flow of electricity rather than water. As a programmer it's wild to think about the absurdly complex process that is set off by high level code. What's actually happening inside the CPU billions of times per second. I'm always impressed by mechanical designs that don't rely on a computer, by the elegance of the engineering. Then I remember that that's also true of a CPU, the parts might not move around but it's the same cascade of interconnected simple components. Freaking wild.
all complex engineering topics are wonderful
I love stuff like this too!
"Look at all the things they need to do to mimic a fraction of our power!"
We first had to capture lightning and trap it in a rock
Here’s a tip for understanding the different layers of chambers: Instead of using a white background with blue water, try using a yellow background. This way, as the blue water fills up the chamber, you’ll see green water, making it easier to visualize the layers how the water is filling it up.
That’s a brilliant idea!
Every video since the gas station pump thing has only increased my respect for the people who can work out these systems that are simultaneously simple and complex.
Simple, complex, and most importantly: almost 100% reliable.
This is 1000 year old technology.
its iterative. they didnt start with nothing and then suddenly produce this, they had basic systems that they combine and build upon to achieve these results.
The combination of chill vibes elevator music and 80s adult entertainment soundtrack to the imagery of a urinal flushing mechanism at different speeds is absolutely on point Mr mould 👍.
I like the fact that no physical valves, springs, flappers etc are needed for it to work. Therefore, in theory, it should last for a very long time with little to no maintenance.
Pretty much trouble free until some minerals clog it.
Yeah, same. That's also probably why the bathroom shown in this video is so poorly maintained 😂
Whoever thought of the fact the water itself could be a valve to block air from exiting is a genius, then executing it is even more impressive.
Issue with most urinals is that urine is acidic, so if you have a waterless system, nothing is getting diluted so it slowly corrodes things.
@@No-mq5lwThere's no urine flowing through that mechanism just water
@@creativecarveciteclimb5684 Have you seen the tesla valve doing the same thing with turbulence?
Midwest USA here! This is how all the fair grounds and older stadiums work!
I always wondered how it worked.
In the US, every urinal does in fact have its own flushing mechanism. Never even knew the "communal" flush design was a thing!
My office has one of these communal flush mechanisms. I’m in the states
You can find them in older systems here in the states, but they have fallen out of favor.
The only time I see these communal flushers is at urinal troughs, which used to be more common. Sometimes you still see them in stadiums. The last time I used a trough was at First Ave in Minneapolis, though I'm not sure if it has a common flusher.
My highschool had urinals that all flushed together periodically. I don't think it used a siphon though, it had a motion detector so it wouldn't flush if noone had been in the bathroom recently.
busch stadium in st louis has troughs, never stuck around long enough to look for how it flushes but i would assume it is the same or similar
Thanks so much for this video. There's a whole community of gardeners using plain bell siphons in aquaponics who have trouble getting the siphon to trigger. Your clear explanation and visual of the system will help design better siphons and reduce these problems. Great stuff, thanks again!
I grew up in the UK, in greenham common. From there I could see a manor house. We visited the Manor House a couple of times, and one time my mom and sister walked into the bathroom and reported that the toilets were flushing automatically all at once. I didn't know what that meant, and I suspected that there was some mechanism besides the roaming ghost that my mother had reported, and now 50 years later, you've given me the answer. Thank you Steve
Hey, I used to live in Thatcham and walked around the common every week.
@@CpnGoose I attended Ecchinswell for grammar school!
Only problem with that is they normally only put urinals with common flush mechanism into male toilets... I wonder if the toilets had a similar system? (But what if someone did no. 2 and wanted to flush it immediately?)
@@stepheneyles2198 so it WAS a ghost after all! 👻
@@stepheneyles2198maybe 2 cysterns? One large, common one and an individual normal sized one for flush on demand
Whoever came with that invention was really clever, a valve and a timer with no moving parts, "very impressive".
As a side note i appreciate the mrmattandmrchay channel for old elevators videos, they are fascinating in their own way.
Let's see Paul Allen's siphon
I can't say it's a strictly British thing but I don't recall ever seeing the urinal flush thing in my 70 years in America.
37 here, and I saw it a number of times as a kid. Not in a while, though.
i think we have those they just hide the plumbing more and trough urinals are thankfully extinct
I've seen it in a stadium in the US, but that's it.
I have definitely seen them in (Canadian) public schools back when I was young. That constant sound of water trickling...
They've clearly been replaced by those electronic sensor/eye things en masse to conserve water as they were flushing all night / weekend / summer when no one is around.
I haven't seen one like that since I was a kid at a beach campground bath house, I'm 32 now, I think I was 9 years old on the camping trip I'm thinking of.
The blue fingers elevate the video. Gives a whole new meaning to "getting your hands dirty" with hard work. :D
Two by two; hands of blue...
@@gdutfulkbhh7537 Ha!! Great reference! :D
I was searching the comments trying to figure out why his hands were blue. Took until I found yours to realize it was probably from the dyes he was using for the water demonstration.
“Whatcha watching, honey?”
“A video about urinals.”
"Again??"
Did she ask when the music started playing at 9:50 ?
@@Meenaia I know, so random
The first person was probably the gay man coming into the urinal for random fun with strangers ;)
@@kjh23gk This one has an emphasis on siphons!
I appreciate that you show your mistakes. Sometimes I feel stupid when I don’t get these setups right away. That’s why I tell myself - this isn’t as simple as you’re able to make it out to be lol
Technically, you should have kept pouring once the siphon initiated, to show that it works even if water keeps trickling into the reservoir (as it does in an actual installation).
That bugged me too!
It empties faster than it can fill.
@@JohnnyWednesday It's the principle of the matter.
@@logiclrd - You can use logic to fill in the blanks.
@@JohnnyWednesday That's not how demonstrating something in an experiment works.
Related, in the aquarium hobby there are overflows that the hobbyists want to keep quiet. But the shapes tend to make siphons, so there is work to do the opposite … keep the draining process quiet by encapsulating it, but engineering it so a siphon doesn’t form.
“Durso standpipe” is one such design.
Reminds me of a transistor driving another transistor called a Darlington Pair. This allows a really small/weak signal to drive a big load. Well done Steve!
I was thinking of the Unijunction transistor, as this mechanism is a relaxation oscillator.
@@liam3284that’s more like this indeed, the pnp+npn equivalent of a thyristor/diac
Threshold + positive feedback
Isnt that’s known in electrical systems as a relay? A small current opens a switch which carries a much larger current
@62Cristoforo no, a relay refers to an electromechanical device where a small electromagnet closes/opens a switch. It does serve the purpose you stated, however there are other ways to control a large curent/voltage that don't require relays.
@@62Cristoforo a transistor is kinda like a semiconductor relay, but without isolation
This finally answers any question I had about how adding water to a urinal leads to this flushing action where the water disappears for a second and then comes back. Truly amazing!
If you pour too much wine into Socrates' cup, it automatically dispenses urine into his fabric conditioner rinse cycle, ruining his togas. Full success!
he'd rather drink a glass of hemlock juice than hear this crap
Why so blue, aristotele?
Did you know that a lot of ancient cultures used ammonia as bleach?
@@shiningarmor2838 Using piss to clean shirt.
Pythagoras 🍷
See en.wikipedia.org/wiki/Pythagorean_cup
That’s way too complicated for me to follow which is more a reflection of me. I love the craft and dedication to something that seems on the surface to be so esoteric. Beautiful physical illustration of physics with the two shades of blue. Youz wunna ‘em smaat kids. Bought a razor too. Thanks Steve :)
The state of that toilet at 1:30 XD still better than the one in Greenwich near the main park gate
Are those rat noises in the background?
@@zsoltlajtos6527 That squealing is probably from the pipes as water squeezes through the tiny holes to flush the urinals.
That bathroom is definitely the single most terrifying thing I’ve seen on RUclips! I have a phobia of public restrooms and I rather spend a week in Aokigahara Forest with no flashlight than 10 minutes in that bathroom. Especially when the flush happens by itself! 😱
You could smell that scene through the monitor!
That transition was almost as smooth as the siphon action! 😄I've used Henson for about 2 years now and will never look back. I don't even use shaving cream--just right out of the shower, zip, zip.
I feel like this two-layer tech really opens up the space of (mostly-)2D models of fluid-dynamic mechanisms, excited to see where we go next!
It's called 2.5d, a special case of fractal dimensions.
Automatic mechanical systems are so much more reliable and cheaper than ones based on electronic controls which invariably give trouble with corrosion of contacts, broken wires and batteries that have to be replaced. E.g. stairs vs lifts/escalators, ball governors vs electronic speed control systems, carburettors vs engine management control boxes, self-steering vanes vs autopilots (for yachts) etc. Thank goodness (Thomas Crapper) for the flush toilet and thank you for the efforts in making this very interesting video!
I worked on autosiphons for ebb&flow beds in hydroponics/aquaponics. They're really fun and once you get them dialled in they are very low maintenance, because there are no moving parts. But indeed matching the sizing to the required outflow and minimum inflow can be a pain. Very interesting to see how they solved that with this multi stage siphon setup!
I like how you show all your "mistakes", because they made you get a greater deapth understanding of how it works (and doesn't) and that feeds into the video.
I still think a few more arrows and a more detailed explanation of what happens at the moment of "flip" occurs would be a big improvement.
Reminds me of when I worked out how a proportional brake valve with loads of chambers worked many years ago.
Nevertheless I still struggled and had to do a good number of replays before I got this.
It's Steve's Siphons -- a subsidiary of Mould's Models
Just wait till he needs to cast a fungus shape. Mould's mold mold
I am not convinced the blades (sponsor of the video) are working well - based on the look of Steve's beard at 12:42. Maybe if you show us how well they work ;)
Another 2D water video, love it!
"You may know this already, but I am already a huge fan of automatic siphons ... " hahaha, what a great way to open a video.
I heard instead that a fast siphon doesn't exist in a 2D world.
I think I've maybe seen one urinal like this in the US, it was at a fair ground and was very old. Every other urinal I've encountered has its own individual flush. I assume this is so you only use water when someone has actually used it, rather than flushing it regularly regardless of how often it's used. The siphon systems seems like it would be pretty wasteful if that bathroom isn't very busy, and like it might be insufficient to prevent the place from starting to stink if it's being used heavily. It does have the advantage of being automatic, so someone can't just forget to flush. That's typically solved electronically with a motion sensor these days, but I can certainly see why someone would have wanted something automatic long before electronic sensors became possible or practical.
I wonder how hard it would be to make an entirely passive rainwater flushing system out of stone or concrete or something... can you imagine? Build the thing one day and for the next 100 years, barring drought, it's just flushing every 20 minutes or whatever. I suppose it'd be pretty hard to keep up a 20 minute flush cycle with just rainwater, but the idea of completely passive flushing is intriguing to me.
@@reaganharder1480 Seems very doable mechanically. But rain water is so dirty, I would be worried about the whole thing being clogged up with grime and algae pretty quickly.
I love the way you show your mistakes it shows that even the brilliant dont always get it right every time.
7:12 Lol you did an inverse of the classic "I'll drill a hole to fix the leak in my hull"!
It's always funny to see that happen with overthinking
I can't speak for other parts of Australia, however when I had a plumbing business in Sydney with my brother we installed heaps of these in schools in the 1990s. We converted quite a few of the old pull chain, overhead, urinal cisterns to siphonage cisterns.The big advantage is no moving parts, (in the cistern) so minimal maintenance.
To minimise water wasteage they were always connected to the mains supply via a check valve and an electrically operated solenoid valve with a ceiling mounted motion sensor so the cisterns would only fill and empty when it detected someone at the urinal and not while students were in class for extended periods. That toilet you filmed in is cleaner than some of the ones I've worked in.
I am in awe at your curiosity about tricky physical phenomena and ability to set up experiments for them. I am really impressed at the frequency with which you upload videos, *each of which* is about an unusual or counterintuitive aspect of physics AND has beautifully filmed experiments for it. Awesome job!!
9:46 Is the syphon so sexy? Or why that music?
I marvel at the genius intellect that came up with this in their head and then built it by hand
Probably the Einstein of urinals. A real genius. Hoe on earth did he/she figure this out?
I don't have anything interesting to say besides thank you Steve, for being a great teacher and a role model for an aspiring teacher. This is a mechanism that wouldn't be possible to approach understanding in 10 minutes ever before (without a very good plumber on hand anyway), I reckon. It was very satisfying to see this maze of pipes turn into areas of pressure and flow in my mind.
I saw one such urinal in Slovakia. It was used to very recent day. But the flushing did not work (probably for ages).
When I tried t enter through the door, it was like there was invisible barrier and I could not physically pass. The smell was that strong.
They are all like that. And their jacked up teeth. And they are still shitting in the sain. The Olympians with feces by the liter in their guts. They all stated that the water was in fact, not cleaned up. Over a billion spent and literal turds still afloat. Unreal filth. USA, I guess.
they do not have a great reputation for fixing things.. they just accept them as being broken and live in squallor. :(
I had already purchased the Henson AL13 and it really is a game changer. I don't get ingrown hairs anymore. Great video by the way.
Have you ever heard of the "Clock of Flowing Time " in the Berlin Europa-Center? It's a realy interesting display with loads of syphons.
This is pretty cool I've been using a similar design in my aquaponics for a while and didn't even realize it. I built a bell syphon and made some modifications and I just realized, I somehow made exactly the same thing you just demonstrated in this video. Wild I didn't even know this already existed would have made designing mine much easier.
A Trainspotting reference is always appreciated!
Came here to say exactly this. Steve's nearly at Map Men levels of niche references! 😊
I too say, “Cheers to that!”
Cinema version even. Tho it seems there are very many versions of that movie, so maybe it is in more versions.
While in Czechia back in May, I used these urinals several times in one of the buildings, and was flabbergasted that it seemed to “know” when to flush. I searched for sensors. I searched for a peephole, imagining a small elderly Czech man waiting for me to relieve myself to a level where flushing was necessary. I finally decided it HAD to be associated the the water level when urine was added, but didn’t know the exact mechanism. This is amazing.
The only urinal that I've encountered this at here in Canada was in some of the boys' rooms in my high school (built early 20th century). To save water they'd shut off the valve about an hour after classes ended and locked the door, so if you ever stayed for late activities you had fewer bathroom options.
I dont know if they shut off the urinals in my school, but for school age boys, we would have just used it anyway.
I just discovered YOU. I'm a mechanical engineer (retired) and kept wondering WHO invented this. Did he (or she) get properly compensated? While I watched I also thought, "Wow, this is similar to the old Fluidic systems." Then at the end, I see you have a video about a water computer. I haven't watched it yet but I was taught control systems, which included fluidics just as digital computers put them out of business for most industries. While in college I worked construction jobs where the business buildings had fluidic HVAC systems. They definitely have some advantages.
-- I'll be seeing you again. 😃
Like all good things, these mechanical devices have now been offshored to a team of low paid IT workers monitoring security cameras placed at each urinal. They use their expertise in remote desktop control to flush the urinal when one finishes using it. You can tell an operator is monitoring by the little red LED that lights up behind the smoke stained window in the control unit above the urinal.
It's a low level AI, not even a human. An AI don't care about the size or shape of your apparatus.
You just gave someone a whole phobia about peeing in public 😂😂😂
I knew someone who worked at a remote toilet flush facility.
Each worker had 2 screens and could connect to as many toilets as they could handle. The more experienced workers could take care of a busy rest stop by themselves, but the newer recruits had to take on less work.
They were paid by flush, and if the person manually flushed the toilet they lost that pay for being too slow.
I am amazed at the number of people who dont even understand a simple siphon. Have used (manual operated) siphon all my life. Used to drain my moms swimming pool for winter (and during the winter as rain re-filled it). Loved being able to walk away and know when it got low enough it would shut off but it had no motor or moving parts and used no electricity.
Choose life, choose a washing machine, choose a **** colour TV... I know what's on my playlist for the weekend!
Loved the reference! Thank you
Even though I don’t fully grasp the exact processes I do appreciate the level of concentration and genius required by whomever designed this device.
10:10 That’s great music for hanging around in men’s toilets with a camera! 😅 The good old days of cottaging!
"for handing around in men's toilets" LOL! At first I thought that was a Freudian slip, and you meant "hanging around", but then I googled "cottaging"!
@@backwashjoe7864 Oops!
I remember my dad's real ale festival cooling system. The barrels had cloth sheets over them with long pipes with small holes drilled in. Then a urinal system was used to pump a flow of water through the pipes on a regular basis keeping the cloths damp. It worked really well.
I too hate that dribbling problem 😂 Great video as always!
Have you tried super glue?
🫣😬😁
I feel "Steve Mould solves his urinal dribbling problem" seems like a better name for this video
You should see a doctor about that.
@@ArchangelExile I know it is a light-hearted banter reply, but no joke for a moment. If at any age, but more commonly above 50, you have dribbling problems, that may be a sign of something wrong with that gosh-darned prostate.
Canadian here. Never seen a urinal flush purely using physics. It either just goes down and empties like a normal drain (they're at waist height instead of being on the ground) or other times there's a sensor that will flush it with a surge of water when it detects a human is there, and when the human leaves, initiating a FLOOSH!
The reference to the movie Trainspotting was one of the most unexpected things, but honestly, I loved it, this movie marked my adolescence hahaha❤🇧🇷
I really want to see him climbing out of the bowl now.
When he spoke of the worst toilet in Beckenham I immediately thought about that movie. RUclips didn't disappoint 😁
Are you okay as a person? Trainspotting has nothing to do with trains...
@@thomasrogers8239 I'm not sure what you're trying to say? Why wouldn't he know what the movie is about?
@@thomasrogers8239 I'm pretty sure if that movie marked their adolescence they definitely have seen it and know what it's about.
Steve is like that Physics teacher you look forward to going to class for. I think most physics teachers are cool.
2:05 - how did you know about my dribbling problem? Who blabbed?
There’s so much elegant engineering all around us! It’s so cool learning about all the magic tricks in the world
1:39 Don’t know about the rest of the world, but the US definitely doesn’t have that. In fact, we don’t have that kind of massive urinal; all of ours are individual units. The only thing I recall that comes close to it are these trough looking ones that are at my nearby renaissance fair, and I’m not even sure if it has a flushing mechanism at all or not.
Edit: Actually, nevermind; thinking about it, I think my local fairgrounds has (or at least had) that communal urinal. Weird that they’re both at places with the word “fair” in them.
Petition to call the 2D version the "Nebraska Siphon".
Reasons: The back side looks vaguely like the American state of Nebraska, Nebraska literally means "Flat Water", and also, there's just something goofy about naming something after a forgettable place.
Don't worry Nebraskins, as a North Dakotian, I feel your pain.
What place?
nebraska siphon sounds like some obscure sexual act you find on the urban dictionary
@@freshstat1csnow Do you want to be the primer siphon or shall I?
@@uss-dh7909 like ND, but more corn... also Fargo is famous... ;)
(you have to have a shovel in the van)
I know some others mentioned this, but you gotta keep the water running while draining to reflect real world install. This also introduces another variable in the ratio between in and out flow and how tuning those two affects function. :)
Also, you can fix your original, more simple, siphon by adding a 90 degree bend at the outlet with an outfeed pipe. Anything more than 90 degrees will introduce hydraulics, which will create inconsistency. And you say no moving parts, but a pump has to create pressure in the lines. Unless we’re talking about a rain fed, gravity pressured urinal. Sorry if this reads as critical… this video was just super interesting to me as I’ve puzzled over this exact problem with hydroponic gardening. Huge fan and love your videos!
That urinal design feels like whoever originally designed it was trying to make the experience of using it as close as possible to pissing on the wall in an alley outside the pub like it's 17th century London.
In Hong Kong, pretty much all the public toilets used that auto siphon. The school I went to also used those in the toilets. The ones inside more modern buildings have the IR sensor flushers, though. In contrast, I have not seen the auto siphon in Japan, only manual flushing or IR sensors.
Ps: I think it is interesting to note that HK, a former colony of Britain, has very similar designs to those shown in the video, while Japan, which was not a colony, does not. It would be interesting to see if there is a correlation between being a former colony to the auto siphon usage in toilets.
I found a glassware automatic syphon in an old drawer at work and played around with it for longer than I care to admit. It's fascinating.
If you're thinking of what I'm thinking of, I've seen these, in use in life science labs, even into the 2000s, and the lab I work in used to have one but never used it. They were meant for washing reusable glass pipettes, which is good from the standpoint of reducing plastic waste, but terrible from the amount of water they use, because they are nowhere near as sophisticated as shown in this video, so a fairly high input flow rate is required for them to work, which is a fair percentage of the exhaust rate, so a substantial portion of the water that goes through doesn't actually do any work cleaning the pipettes, and the top parts of them get much less soaking than the bottom parts.
@@Lucius_Chiaraviglio Ah, I know exactly what you mean but that's not what I was talking about. The ones I have are part of a jointed glassware set and are much smaller, made of glass and transparent.
Bizarrely I can't find any photos of them on the internet, so they must be relatively rare. I imagine quite expensive too, as it's fairly intricate glassware.
I've been wondering for YEARS how the hell did my washing machine's soap reservoir work, and you finally explained it, thanks
I have never seen a urinal that flushes periodically
When did you think they flush? never?
@@JohnnyWednesdayyou don't have to flush urinals in the US
@@MaddSpazz2000 - you just let the urine dry on the ceramic?
@@JohnnyWednesday Well usually urinals have some kind of sensor that flushes them automatically when you leave. Isn’t this a huge waste of fresh water?
@@abc321meins - Oh I see what you mean - no this is Britain, the one thing we never lack is fresh water. It rains so much that we're immune to waterboarding.
I built one of these to make an old bath into a garden pond filter, it took a bit of tuning but it worked like a dream as a hydroponic system to filter my pond and grow various plants
I don't normally comment on sponsors but I've had my AL13 medium for a couple of years now and I love it.
9:27 _Through the magic of buying two of them..._
1:17 "Oh, me? I'm just here to look at the urinal siphoning!"
I've often wondered how a toilet worked but never been quite curious enough to look it up. This is actually a lot more interesting than i thought. Very cool.
10:00 classic 80s retro porno music. Quality music taste
Fricking love a new Steve Mould video! Such a simple everyday device we take for granted… who knew it was so blinking complicated!!!
So... if anyone in Beckenham finds a public toilet with a missing syphon, I have an idea where it might have got to.
It's a compound syphon, you see these sometimes in the traps of condensing boilers to quickly remove waste water colllected from the flue that accumulates very slowly.
I wasnt expecting Grian to put me on hold during a Steve Mould video at 10:30
Bruhh
I appreciate the number of times you had to try this for the video. The evidence shows in the blue fingers.
Water transistor?
That was my first thought too
I have only seen US communal urinals at large parks and state fairgrounds, but I've never noticed the flushing mechanism. Very cool to watch it happen!
11:09 Looks like a giant slug.
I use a straight edge razor for years now. Never clogs, never needs a new blade, doesn't matter how long it's been since the last shave. Just a few strokes on the strop and you're good to go. Yes, it takes a little time to get used to, but you'll never have a better shave than what can be achieved with a "cut throat" razor and some patience. The whole experience is quite "zen" too...
1:16 "if you spend long enough at a urinal" Either see a doctor, or I hope the police catch you.
Great video as usual. Here's an idea for future near-2D models: make the required 3rd dimension using bypass hoses going in front of the system. For example, this system would have required one bypass hose and if you had connectors for such a bypass pointing towards the camera, you could have one transparent pipe going horizontal in front of the 2D model making the whole model practically visible at once, especially if the hose is positioned to avoid hiding any corners or connectors in pathways. You could probably use connectors meant for PC water cooling to attach hose to flat piece of acrylic and also use hoses meant of PC cooling. If you build things carefully enough, you can probably use hard tubing which should result in very clear image.
For all the women watching this who have never seen the inside of men's restroom: this system is used above a large trough because the men are too drunk to aim.
I cannot speak to the rest of the world, but in the US it mainly exists in bars and some public event venues, most places have individual stalls.
Intrigued by the Henson razor sponsorship. You said that it took a while to adapt to it. Yet you have a full beard? Love your channel, but this made me smile. 😊
At this point Steve is gonna start the next great flood
Next?
I think I can use some of these concepts to build an automatic system to water my carnivorous plants.
I need it to trigger when the water level is low, and stop when it reaches the high level.
Thanks for the inspiration!!
1:18 no, I am not familiar with the moment all the urinals start flushing
Steve, I absolutely love the Henson safety razor! I bought it in December last year and have changed to my second blade just recently. Great suggestion! Thank you for it!
Why are you using sanitary towel fluid in your syphon?
lol
As always, your videos are a delight to watch irrespective of whether or not at the first go, I am able to comprehend it completely or not!
It was widely used in schools and kindergartens in former USSR. Finally, I know how it works. Thank you.
Great video. I was planning to build a bell siphon for dumping condensation periodically, but with the slow accumulation makes that not work for the reasons you mention here. Thx for this!
Interesting for sure, and the little changes between the working and bloody machine are so fine.
Haha, the blue stained hands show the dedication 👏. Your demonstrations of these “fluid dynamics”* always remind me of microfluidics. I would love if you made a video about them and attempt to make scaled up versions!!! Not sure if it could be scaled up due to the difference, but your explanations and exploration would be fun and interesting to watch nonetheless!!! Cheers!
Yankee here. I’ve never seen this in my life. Our urinals, basically without exception, are individual units with individual flushing mechanisms operated either by lever or by proximity sensor.
0:54 water of life
Men are forbidden to drink it
Lifelong American here! Piss troughs are uncommon, and even less common is an automatic flusher. I had no clue something like this even existed.
Nicely illustrated and explained. Big Clive did a teardown and analysis of one of these a few years ago, but this video goes into a little more depth.