Vacuum Packed Tank Car

[kws4000]

Seeing this discussion about steam condensing into water [supposedly] could cause an implosion, then what about the steam condensing into water in the cylinders of steam locomotives? If the steam valve and cylinder cocks are closed, would the steam condensing into water result into [at least] a [partial] vacuum?

True it condenses, but not that much. Running light, hooked up mostly with throttle barely open, a mere wisp of steam flicks into each cylinder each stroke. It expands rapidly, loosing pressure and gaining volume immensely. This is an irreversible process, and transitioning from the superheated point to saturated point, heat energy is expended and converted to work (albeit not much, because we are running light). As heat is converted, the temperature drops and water condenses out of the steam.

Once the cylinder reverses stroke, ideally the water remains suspended in the vapor, and is whisked up the stack. If any water remains behind, eventually it will accumulate and occupy volume. That extra water will absorb further energy from incoming steam, causing more water to accumulate. Eventually, if enough builds up, because water is a non-compressible fluid (for the sake of argument), it will blow off the cylinder head, leading to severe delay/derailment/wreck. That is why you need to open the cocks periodically.

Something was designed to prevent such occurences, but I forget what the name is. With superheat, this problem was greatly alleviated. But if there was a vacuum, then you would use a snifting valve, mainly used with saturated-steam loks. High temp air admitted if using superheat would burn the lube oil, leading to failure.

But honestly, if a cylinder can withstand 300psig in one direction, I would expect it to withstand -15psig in the other. Not that it ever got that low, but still, if you can prove me wrong, please do so.

 

[Infraredbob]

Sorry we messed up your thread John, but my intent was to protect you from misinformation such as a) the pressure -200 psi, b) this video is steam accident training, c) a cylinder is the most stable structure, d) the water in the video was actively delivered, etc...

Dude you're good, I didn't really understand anything you guys were talking about anyway. The problem is that my lack of knowledge about this kind of stuff makes both of you guys sound pretty convincing, even if I didn't get what the debate was really about

John

 

[narrowgauge]

A cylinder with thin walls is effective in containing pressure because the parallel portion of the tank has the steel in tension and would probably be made from High Tensile steel. Internal vacuum implies that there is external pressure, now the steel is no longer in tension and is not self supporting. Cylinders intended .to support a vacuum need thick walls and internal bracing.

Think of a ordinary rubber balloon, inflate it and it will stretch to contain the pressure an if you continue to inflate it, it will burst when the rubber exceeds its tensile strength limit. . If you suck the air out the balloon will collapse. it is not stiff enough to resist atmospheric pressure. Soft drink bottles will react the same, they come to you containing fluid and gas under pressure, try sucking the air out of an empty one and it will collapse like that tank car.

Peter

 

[cascaderailroad]

Sorry we messed up your thread John, but my intent was to protect you from misinformation, such as: "this video is steam accident training"

Where do you get your misinformation:

a) That the video is definitely "NOT from steam accident training", neglecting to open the tank car top cap, which would have caused the vessel to collapse ?

I suppose that it was also (in your expert opinion) b) That the video is definitely "NOT from improperly draining the filled vessel", neglecting to open the tank car top cap, which would have also caused the vessel to collapse ?

And I am supposing that your explanation is that the RR deliberately wanted to hook up their brand new tank car destruction contraption: the Harbor Freight - "Vaaccuu Suck O Matic 9000", just to prove that the: Harbor Freight - "Vaaccuu Suck O Matic 9000" was their fun new toy, being that the: Harbor Freight - "Vaaccuu Suck O Matic 9000" is best means possible to SUCK a tank car flat ... why would they employ such a SUCKY device ?

And too, SUCK on a Booger King straw real hard and see what happens ... the straw colapses ... if the: Harbor Freight - "Vaaccuu Suck O Matic 9000" was connected to the hose to the tank car, wouldn't that also SUCK the hose flat, just like the Booger King straw ? That also must be one heck of a strong air SUCKING hose they are using, hooked up to the: Harbor Freight - "Vaaccuu Suck O Matic 9000".

Your theories are so flawed, that this idiocy of the explanation of why the video was devised in the first place, is ludicrously absurd ... As the reasoning behind devising the RR training video, for public view, was definitely NOT a video display designed to test out the destructive capabilities of properly using the, way cool, brand new, high tech: Harbor Freight - "Vaaccuu Suck O Matic 9000", to show the public of the: Harbor Freight - "Vaaccuu Suck O Matic 9000" superior tank car SUCKING capabilities.

You just don't make sense !

a) Improper Steam Cleaning ... or b) Improper tank car emptying techniques, using a siphon hose connected to the tank car outlet ... in both cases, neglecting to open the tank car top vent cap ... are the only 2 possibilities "OF WHY" the video demonstration was designed, for a training exercise to RR employes, and the public ... But then again you seem to believe that the RR used a high tensile Booger King straw, along with the: Harbor Freight - "Vaaccuu Suck O Matic 9000" to prove that the: Harbor Freight - "Vaaccuu Suck O Matic 9000" was a really cool FUN new way: to SUCK a tank car flat.

I'm sorry ... but don't look now ... for your lack of reasoning, and theoretical intelligence is showing.

No where in the video did they say that they SUCKED the air out of the tank car AT ALL ... or that they SUCKED the air out of the tank car AT ALL, by by using ANY DEVICE ... let alone hooking up their brand new, superior, the high powered; Harbor Freight - "Vaaccuu Suck O Matic 9000", tank car air SUCKING out device, and quickly opening a magic "BALL VALVE" ... Yet you seem to enjoy this novile explanation of the: Harbor Freight - "Vaaccuu Suck O Matic 9000" being the cool brand new means, and preferred device, to SUCK the tank car flat.

Wouldn't that be akin to NASA, deliberately duct taping a stick of dynamite, to the hydrogen fuel tank of the Space Shuttle Challenger ... Just to show the public, the proper, way cool, new technique, to destroy a vehicle ???

Your flawed theories, and expert opinion misinformation's, just DO NOT make any reasonable sense !

When a RR company sets up an expensive destructive demonstration video ... They do it for a specific reason ... In order to make a graphic video display, for the employees to witness, of: "Exactly what NOT, to DO, in the workplace" ... "So as to prevent tank car collapse accidents in the workplace" !

I ... REALLY do NOT, think they did this expensive exercise, just for the "FUN" of it !
Nor, just to show what the: Harbor Freight - "Vaaccuu Suck O Matic 9000" can actually do, to a once stable, sturdy, tank car !

 

[kws4000]

cascade, your excessive sarcasm renders your argument invalid. That is all I will say, as deneban is quite certainly right, as I am in school for my mechanical engineering degree. As for creating a vacuum, my high school chem teacher had a small model, could produce about -5psig. Weighed about 30lbs. But then again, that was 4 years ago, so specs elude me. And no, the hose did not compress; it was 1.5"OD x .25"ID of solid rubber. But still: sucking a tank car to 0psia (or anywhere else in the range) in normal service is prohibited.

As a matter of opinion, given that this car is of EU design, I speculate that this test was performed to verify compliance with various governmental safety regulations to permit intercontinental commerce without transloading. You ever hear of destructive testing? How do automobiles get their safety crash test rating? Yes, car companies spend years on design, millions on dies and CNC programming, and if the design doesn't cut the mustard when put under the hammer, they wasted their money. But such a waste of money instills consumer confidence and promotes their product as trying to be better than every other out there.

 

[cascaderailroad]

So there are 2 people with swollen ego's, supporting the use of the: Harbor Freight - "Vaaccuu Suck O Matic 9000" to suck the tank car flat ... How absurd !

When there are 2 other much easier means to suck it flat:
a) Steam cleaning contraction, (neglecting to vent the tank car top cap).
b) Draining it through a hose, (neglecting to vent the tank car top cap).

Just because the original re-poster of the YouTube video stated otherwise, he also might have been totaly in error, just another 14 y/o "Village Idiot", typing what he "supposedly" thought happened.

Lets make a bet ... Contact the actual Railroad Tank Car Company (Eva Eisenbahn Verkehrsgesellschaft AG) that made the original video demonstration, and get them to acknowledge that they used a suction device such as the: Harbor Freight - "Vaaccuu Suck O Matic 9000" ... And I will leave Trainz forever ... and smash my PC flat ... and eat an entire straw hat, filled with a can of ALPO Dawg Foodz.

Prove it, or shut up !

There have been thousands of improper tank car steam cleaning/improper tank car emptying, accidents worldwide ... That is a fact ! And for those reasons alone, the video demonstration was designed for in the first place, to prevent accidents !

Just because: You are: "presently in school for a mechanical engineering degree" ... and "he" is a supposed plant engineer with no actual certified qualification experience ... doesn't make you both experts on what took place in the video ... I believe that you both are wrong. Even experts with a degree in: BS (Bull Carp), or a degree in: PHD (Piled Higher and Deeper), experts can be totally WRONG !

As I said, there are 2 very much easier ways to suck a tank car flat ... BOTH ways, through maintenance negligence/improper materials handling negligence (listed above, see: a) and b) ... why would they choose an 3rd ridiculous method, using a device like the: Harbor Freight - "Vaaccuu Suck O Matic 9000" ?

That 3rd theory just DOESN'T make any sense at all !

As for a video display of "destructive testing" ... the so called test failed miserably, and the RR Company would have been so embarrassed, that they would not have released the video to be viewed, as it would insult their tank car design, and discredit their Company ... Both your arguments do not hold water, at all, not in the least !

[video=youtube;mwh3601eGKA]http://www.youtube.com/watch?feature=player_detailpage&v=mwh3601eGKA[/video]

http://www.nordkurier.de/cmlink/nor.../stromausfall-lasst-tank-implodieren-1.519142

 

[JCitron]

Why keep arguing about this? Think about it for a minute...

Whether it is air that has been cooled suddenly, such as steam, or air that has not been reintroduced into a closed vessel, this same thing will occur. You can do this yourself, if you have the lung power, on a soda can or an empty milk container by sucking out the contents without introducing any air replacement. With the steam, it's a matter of the hot moist air not taking up the volume of space as it's cooled suddenly. With air the same thing will happen. Think of a balloon that has been filled up with warm air. As the air becomes less dense, warm air being denser than cold air, just like steam is, will cause the balloon to collapse and return to earth. This is how our weather works as well. Simple process.

John

 

[kws4000]

Why does it matter which method was used? Physics is physics, heck it's the law, and you can't change it. In fact, if you are so determined to get the facts, why don't you ask them yourself?

As for destructive testing, why do we smash automobiles into barriers? To prove the design works. Why do we drop tank car domes onto slabs of concrete? To verify that the valves will be adequately protected at 25mph, in accordance with Federal and industry standards. Why did we smash nuclear flasks with a rocket-powered locomotive? To verify that they would not leak, period. Destructive testing for mass-produced components is standard and expected of suppliers.
At my internship, my company was making bearings for GE. Even though it was not a new design, this bearing from our plant in China had to be certified that it met GE specs in a similar manner to bearings made in our USA plants. How do we do that? Destructive testing, up to 50million revs at 200rpm with measurements every 5mil revs, with an identical load to that in actual service, even though actual service speed is 171rpm.

 

[Infraredbob]

Does anyone know a way to take a thread down?

 

[cascaderailroad]

You can request that the thread be closed, by typing: "Moderators please close this thread".

It's pointless to argue anymore, as so many feel that Eva Eisenbahn Verkehrsgesellschaft AG used the: Harbor Freight - "Vaaccuu Suck O Matic 9000" to implode the tank car.
That's how I would do it. I would absolutely think that it was an absolutely ludicrous means, that: a) steam cooling down in a sealed tank car ... or b) simple gravity of draining a liquid out of the bottom of the sealed tank car would ever cause this ... Not in a million billion trillion years ... Not gonna believe it !

Why on earth would anyone use factual: Steam cleaning accident incidents, and factual: Improper unloading technique accident incidents, as the cause of the collapse ? As we all know that these things don't ever happen ... and besides, these accident incidents would always cause a more kinder, more gentle, slow motion, non-distructive, collapse ... like a Minute Maid Juice Sippy Box implodes when you use the: 9000 HP Harbor Freight - "Vaaccuu Suck O Matic 9000"