Curing Concrete by refrigeration? (Like Hoover Dam)

Could you do one on fluid dynamics of gases (ventelation systems, tunnels, etc)?

Is grainlock something that might interest you ?

I like Tyzoids idear

Prestressed Concrete

That is insane. Exactly the kind of failure that this video was talking about.

Makes a good case for redundancy, a few hundred for a second vacuum breaking system or a few hundred thousand for a new tank.

probably even the lost milk alone would've covered up the price of a redundent valve.

Oh boy you need some milk! lol (also did the milk spoil then you would have a loose version of cottadge cheese)

How did you fight off all the skeletons seeking calcium?

I too, was hoping to see a weak piece of pipe imploded from the negative pressure.

xWood4000 ... indeed, the title sort of implied that was going to happen.

That's what caught my attention. I never thought it was an issue, at least in the residential scope I was considering.

There's a crack on the pipe...

instead you got click bait lol

Me: "This thing takes forever!" *pulls out electric drill* 2000 rpm go brrrrr

Depends on the valves and the pressures you're working with. I have seen more lines blown out of the ground by slamming fire hydrants down by firemen though, you're right. But then I worked in a water system in the mountains where typical pressure was in the range of 250 psi with maximum pressures reaching 500 plus or minus. Makes things a little more interesting than most systems. Scary even sometimes. Large older lines are more prone to collapse, even slight sustained pressure drops. I was working in Chicago when they took down their intake line from the crib offshore and it collapsed in response, Oops. The cribs sit about a mile offshore at both of their plants. Luckily there was a second. Tough to replace a 750 mgd source quickly. lol

@@manueltodesschnitzel3097 I had the same thought. Hilarious

@@beebop9808 I'm always afraid whenever firefighter test fire hydrants because they always slam the fire hydrant off. They do not learn

@@YoureASquidYoureAKid lol I left water system maint. 25 years ago and got into the control side contracting. But they certainly hadn't learned squat by the time I left there. We tried often to educate them but it seemed to be like throwing hand fulls of crap at a screen wall. Just never would stick. lol

crni195 if you knew anything about design engineering, you would know they do process and system design.

crni195 are you saying that chemical engineers have no real purpose?

Who cares what kinda of engineering he does, he obviously just enjoys learning.

+zachell1991 This.

@crni195 I'm a chemical engineering student as well. You have no clue what chemical engineering is if you don't understand that we work a lot in fluid dynamics. Have you ever considered how many miles of piping are in a chemical plant? We don't just design chemical plants, though. Any sort of manufacturing process has chemical engineering involved.

If you have no money that you can't donate that means you should just donate your excess money silly.

bennyty no, definitely not, because he's going to need it in the long run. What he can do, however, is watching ad's. Instead of calling someone silly, you might want to use constructive criticism.

Don't worry bennyty, I understood your joke.

You’re donating by giving him views and likes and clicking subscribe button

Your English is fine, there are lot's of native speakers that generally have a lower standard when typing

In germany , you can volunteer??

@ PreppingfürSchüler Wir können Sie verstehen und das ist wichtig, weil die meisten Menschen die Englisch sprechen immer wieder tun als ob es nicht zu verstehen wäre. Gruß von einem Nachbarn in Belgien 🇧🇪.

@@Hi.Al. yeah you can, in the small towns the fire fighters usually are just volunteers

@@thomgt4 thank you very much for that info. I am in shock , in my country I can't even get a small stupid job as volunteer , firefighters are like the holly grail , no volunteer and they are military so big wages. I am literally in sock , I don't know what to do.

TheMr77469 or over use of a concrete vibrators or not mixed properly

TheMr77469 And for dessert - misplaced reinforcement bars?

Also, in construction in cold climates, concrete that froze before it fully cured, and later thawed.

Matthew Shultz I think that’s a reference to the KZfaq channel by that name.

Tony Yarusso ohhhh that makes more sense

Also 'washboards' for those who drive on dirt and gravel roads... and things that you can do to mitigate them (Mag chloride, various other binders)

He did one on sinkholes. Not sure if those are the same concept.

Nolan Palmer nope, not necessarily. Sinkholes are caused by water under the surface where as most potholes are caused by water and mechanical forces at the surface.

saihenjin www.korresproject.gr

Water gets in road, water freezes, water expands, water breaks road

Haha yeah, that was the joke about it not being a scientific observation, but I don't think it came across quite as well as I planned ;) Anyway, the pressure in San Antonio that day was about 31.5", so it wouldn't be impossible. Yes, this is an issue with larger pipes. Most small pipes can withstand vacuum pressures because of their cross sectional geometry.

I'm a researcher in a lab that does a lot of work on implosion of thin shells (tubes), the dynamics behind it were described by von Mises, you should read his paper. It's a condition called dynamic instability. With the vacuum acting on the pipe (equivalent to saying the external pressure pushing in), there is, up to a certain pressure difference, equilibrium between the pressure potential loading the pipe and strain energy within the pipe material exists. The round shape is said to be an equilibrium configuration. After a critical threshold, more equilibrium configurations start to be valid for a particular pressure, the round shape is capable of balancing the load, but so is a flattened, deformed, imploded shape. Because multiple equilibria are valid, the pipe can arbitrarily jump from the round configuration to the flattened, which it does due to the slightest imperfection. The critical pressure is a function of the pipe wall's bending stiffness, which stores the strain energy. Smaller pipes (with smaller inside radii) can withstand much higher pressures because the internal moments set up by shear stresses have much less leverage to act over. So it's actually the larger pipes that are more susceptible to implosion.

@@PracticalEngineeringChannel I was disappointed. I wanted to see a pipe implode! Even if it was a thin plastic, but better if glass. :D :D Could also have shaved or sanded the sides of a section of pipe to see them collapse.

@@PracticalEngineeringChannel Correct. Small pipes don't care. We had a sewage pumping station rising main with 36" concrete lined steel (thinwall) pipes and large anti-vacuum valves. The valves used to suck in huge noisy gulps of air and leak sewage 'on the rebound' and the operators found the best way to prevent that was to shut them off, when all the objectionable symptoms miraculously disappeared. When I was asked to look at it I nearly had kittens. With the valves offline, those pipes were pulling almost a full vacuum on pump stop and how close they were coming to an incredibly expensive 'whump' I don't know. (And calculations didn't help much because the equations for collapse of a thinwall pipe under internal vacuum depend directly on the assumed eccentricity of the pipe wall). But I suspect it was much too close for comfort.

Dan Teall. Had to look through a lot of comments before I found one that mentioned cavitation. I'm surprised that he didn't mention it in the video. Cavitation is a huge issue & has extreme power. It Deserves it's own video

Seen a few sewage pump impellers 'eaten' by cavitation.

Bobby Patton Water hammer FOREVER 😜

Could be both! Even when you heat up water, the first thing that happens is that gases get out of solution with the water, and after that water itself gets over into a state of gas. The gases disolving from the water are the reason why you can make better tea if you properly cook the water as it becomes a better solvent by cooking.

You are both right. Some steam and some formerly dissolved gas. The steam would be condensed immediately when the pressure returned, but notice the haze of small bubbles? Not steam.

this. i always wonder about this when i see people using resin in their wood works.

One gallon of epoxy costs about the same as one cubic yard of concrete. There are about 200 gallons in a cubic yard. The price of epoxy will have to come down by two orders of magnitude before it could be considered as a concrete replacement.

there's no way resin is going to replace concrete

What a loaded question dude

+Harman Robotics Or the price of concrete would have to go up by two orders of magnitude :P

I don't think the pressure got quite that low.

Imran is correct. The guage clearly shows that momentarily pressure dropped below 10kPa, water vaporize into steam at room temp.

The Spherical Earth the air would just be pushed through

It depends on the velocity of the fluid and the diameter of the tube. If the velocity of the fluid exceeds the rate at which a bubble will rise in the vertical section of tubing in still fluid, the air bubble will be pushed through. If not, it will rise to the high section of the inverter U.

For what it's worth, an experienced designer or pipe fabricator would never install a permanent system like that. If there must be a high point, an air release valve would need to be installed.

While pumping out my boat last night with a clear hose and a small electric pump I observed exactly the phenomena you describe. As the pump began to suck air, the bubbles accrued at the top of the loop and eventually blocked the flow. When I moved the pump to a deeper spot, the increased and airless flow was able to overcome the blockage and blow the bubbles through, and out of, the hose.

@@osubucks2010 Would you still need an air valve if the downstream pipe of the air valve is atmospheric/open-ended? Given that the end point is of a bit lower elevation.

How did it go? I am an engineering student.

@@lordflufffluff This comment didn't really go anywhere, but I found data online probably a couple of weeks / days later :) now I'm working as a researcher on topics connected to the energy transition

@@eL3ctric cool.

@@eL3ctric Look at Geberit Mapress datasheet.

@@garagentor1855 oh shoot! So close man! Only three years behind

The negative pressures talked about in this video are not an issue for a washer. Any arrestor device installed upstream from the valve would have no effect (on negative pressures). It is what happens after the valve that causes the negative pressure. Arrestor devices will however dampen pressure spikes cause by fast shutting valves.

It certainly wouldnt hurt to put them on if you bought them already. Some valve types are designed to shut off slowly, (Diaphragm valves with a hole of a carefully chosen size in the diaphragm) and some slam off/on (like a solenoid valve) Ive noticed some washing machines have a distinctively slow turn-off, which would reduce water hammer. Also, use the stainless braided hoses instead of the plain rubber ones to run from the wall to the machine too. When the rubber hoses fail (rubber hardens, cracks eventually) they end up bursting and dumping a lot of water. The braided stainless ones last longer as its steel rather than fiber-reinforced rubber providing the strength,.When they fail the rubber liner leaks, but as its contained by the steel, rather than bursting you get a much smaller leak which can hopefully be caught before its caused a ton of water damage. Finally, if its not in an unfinished basement where a slow leak wont hurt anything, consider a washing machine pan too. The price for all the accessory bits can add up, but $100 wont even begin to touch water damage repair if something goes wrong.

I agree with all of your information except for the hoses, all the stainless steel hoses are warrantied for 5 years, versus the rubber hoses at 7, both should be replaced at these times - i can buy the rubber ones for 1/3rd the price and set a boomerang Gmail e-mail to remind me to replace them in 6.5 years. I prefer proactive maintenance on hoses. Thank you for the information about the diaphragm valves.

It's all fine when you have enough of a buffer to prevent damage. Long lengths of flexible pipes are great accumulators

I was going to have a comment like this!

I’m glad someone else thought the same thing!

That's my saying everytime I hear that word! Like mahnamana.

Why Picard...why.

Treblaine -- So, this is the "Phenomenal man"? Haaah! I love it

Yes definitely. That’s why I joked about it not being a scientific observation

True, didn't notice that line, thanks for replying! Faster instruments are probably 10x the price, not so "backyard" ;-) I was expecting a thin metal/plastic pipe that would collapse when the valve was slammed shut, just another idea for later

The return time of the wave is dependent on the length of the pipe (among other things). In a real-world sewer rising main of, say, 1000 feet in length, the pressure spikes are several seconds apart and you can easily see them on a gauge. However, it's not the negative (vacuum) spikes that are alarming, so much as the 'rebound' when the gauge needle goes off scale at +100psi and whacks against the zero stop from the wrong side :) (Yes that shouldn't happen. There was an anti-vacuum valve incorrectly set up).

Ambient air pressure was over 31" Hg that day. I made an obvious joke about how my guess was far from a scientific observation. I don't think it quite reached 30" below ambient but I think it got close.

I sort of love the fact that I didn't catch the joke in the video. It means I'm in the right place, to learn some more that I didn't know! Thanks for the video and for once, the comment section as well!

I hope he had surge reducers between the house and the valve in the video

Yup I was thinking the same thing, 14.7 psi = 1 atm = 29.93 inches of mercury. Vacuum is not likely to damage any pipes unless rated for no pressure or a thin walled tank like a 55 gallon drum, kinda clickbait...

@@anime2485 Just depends what your reference pressure is. If you are talking about an oil pipe 2km down on the ocean floor it's a whole 'nother ball game.

Well, is that entirely true? The way that very tall trees get water all the way to the top is through very deep negative pressures which are possible in a pure fluid environment. I'm not sure if you could recreate this effect here though

@@thomgt4 I don't think so. What you mean is probably osmosis, which can create big pressure gradients, but absolute pressure can't be less than 0 atm. Trees also start the water transport in the roots with ~ 1 atm and evaporation in the leaves leads to negative pressure - but at maximum 0 atm (but that could only transport water ~10m up) and according to the source creates an osmotic pressure at the leaf cell walls thus sucking up the water up to 100m. Source: www.scientificamerican.com/article/how-do-large-trees-such-a/

@@anime2485 Most large water mains (say over 30" diameter) are thinwall steel and can easily be collapsed by internal 'vacuum'. They usually have air valves to release trapped air but those valves also perform an even more important role of letting air in if the water pressure inside drops below atmospheric.

Haha, Pressure was over 31 inches that day in San Antonio. I tried to make it clear that my estimation from the gauge was not a scientific observation.

My point is that you are not seeing a peak of over 30 inches but the result of needle overshoot due to the inertia of the mechanism caused by a transient spike. You can however still estimate the pressure of that spike (non scientifically) by averaging the swing of the needle.

Pressure that day in San Antonio was about 31.5". I said in the video the peak looked like it was around 30" below atmospheric but that it wasn't a scientific observation.

*Not* PSI, Pounds per Square Inch, but inHg, or Inches of Mercury. Besides, he is *not* measuring open air or barometric pressure, he is measuring the pressure on a closed water system. You could draw vacuum on water until it starts to boil at room temperature, since water is incompressible.

That doesn't look like a gauge buffered with a fluid to absorb the momentum of the slingshot. Just because it is bouncing past 30 doesn't mean it is reaching 30. There is a bit of a whiplash going on. If you want to talk numbers please get better equipment in the future.

What if you sponsored him instead of just complaining. The idea of this video is not exact digits but getting the idea. Moron

Charles Cox .