h a l f b a k e r yIt's as much a hovercraft as a pancake is a waffle.
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Much better than the conventional thermos, and not much harder to produce, is the Extreme Thermos. It is extreme, in that it works extremely well.
Thermoses work with a vacuum placed between two cups, connected at the top. The problem with this, is that the lid has no insulation, and that the inner
cup is actually in contact with the outer cup, allowing heat transfer, and therefore heat loss.
The best insulation is no insulation. Literally. A vacuum is the best insulator. But contact between two objects allows free heat transfer.
So in the extreme thermos, there is no contact. 6 magnets are placed on the inside of the larger outer cup, at the top, bottom, and sides. On the outside of the inner cup, are 6 more magnets, placed at the same position, with the same pole facing them other magnets. The smaller, airtight cup, with nice hot food inside, is placed inside of the larger cup, all air is evacuated between them, and viola!
The magnets levitate the smaller cup, and disallow contact, while the vacuum between them blocks heat loss!
No manmade vacuum is perfect, but this would hold heat a really long time, cheaply.
Open the valve to allow air to seep in slowly, open, and get the inner cup. To reuse, place the inner cup back inside with its contents, seal, and remove all air via the valve.
The cups are squarish, to disallow rotation.
Extreme Thermos
[FarmerJohn,
May 08 2005]
Cryoport
http://www.cryoport.com/About.html
An example of a company that may benefit by more compact design and improved damping control. [reensure, May 08 2005]
Is Magnetic Levitation Possible?
http://www2.corepow...faq/levitation.html
[xaviergisz, May 09 2005]
[link]
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bungston, FarmerJohn, want to illustrate this? :) |
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//and viola!//
? What's she got to do with it? |
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I'm a bit worried that, when you take the top off, the inner bottle is going to pop out like a bar of soap in Orson Welles' bath. |
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Let the air out SLOOOOOOWLY...... |
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<Psst...>(Viola is pronuonced whala)</Psst...> |
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Would that not be "Voila"? And, for that
matter, "Vwhala", [DesertFox]? |
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Hmmm, how to get the liquid out
without the inner cup popping out...
well it could be held in with thin
microfibers... they could also stop
rotation and allow for a more circular
design. If this is implemented I'd like
the fibers to be known as Eyebrow
Fibers |
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I still don't get this. There is a vacuum
in the gap between the outer cup and
the inner, magnetically-levitated cup,
yes? In the (most excellent) drawing,
the vacuum is in the white space, ie the
space into which the outermost
magnets are protruding, no? So, how do
you get to the inner cup without
releasing the vacuum between it and
the outer cup?
Can we have a
drawing that shows the whole thing in
cross-section, rather than just the mid-
section of it? |
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The midsection drawing is a large thumbnail picture on which to be clicked to see the whole cross-section illustration. It seems the vacuum must be recreated for each usage. |
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Good lord. Wonders of modern
technology! Thank you.
Could it
not come with an integral reservoir
which could be filled with a highly
compressed vacuum? Then a small
portion of this could be vented into the
space after each usage.
(I am
now wondering how much of life I have
missed by failing to click on its
thumbnails.) |
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Basepair, you lost me on that anno. Reservoir filled with a highly compressed vacuum? |
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A vacuum is emptyness. It is the absence of air. It cant be compressed. |
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What are you trying to say? |
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//The cups are squarish, to disallow rotation// |
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How about allowing rotation and gaining some benefit from it by wrapping the inner container in copper wire and generating electricity. This charge could be used to replace any heat lost from the tasty soup contents. |
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Better yet, the cross section does remind me of the inside of a dry cell. Maybe there is something that can be placed between the containers that could produce a charge when a wire is placed with one end in the soup and one in the "something". Maybe not acid unless one routinely drinks lead soup. |
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You can't levitate something with stationary permanent magnets (see Earnshaw's theorem). |
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[DesertFox] Well, if a vacuum is
emptyness, there should be no major
difficulty in compressing it into the
small reservoir. And no, I'm not
serious. |
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I'm with [Basepair]. I don't see how the seal is created to hold the vacuum (and still allow dispensing of the contents) if there is nothing at all physically connected between the inner and outer vessels. |
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Actually, I have a question. The
assumption here is that all the heat lost
from a conventional thermos is through
conduction - either through the lid
(which is normally a plastic plug filled
with insulating foam etc) or through the
rim where the inner and outer shells
meet.
Is this in fact the case?
How much heat is lost by radiation? |
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xaviergisz, magnetic levitation is possible. The page even says that there are exceptions. In 7th grade, in a construction/drafting class, we had to stick 4 permanent magnets on the bottom of a square piece or thick cardboard, and float it on a magnetic track. They most definitely floated. The same principle applies here. |
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For half and basepair:
Both inner and outer vessels are airtight.
Inner vessel is placed inside of outer vessel.
Air is evacuated from between them.
To open, allow air to enter vacuum slowly, via valve
Then remove inner vessel, use contents, and place it inside again
After closing, remove air again.
:) |
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I googled heat transfer and I found that most/almost all heat is transferred by conduction. |
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Fair enough then. But how about
replacing the magnetic levitation (which
seems a trifle dodgy at least) with
filaments (as mentioned above). I can't
imaging that a few nylon fibres
spanning the vacuum will conduct a lot
of heat away. And if they do, replace
them with stiffer helical fibres, offering
a very long conduction path between
inner and outer vessels.
Would the improved thermos
retain the intelligence of the old ones?
They <old joke warning>keep hot
things hot and cold things cold - how
can they tell?</ojw> |
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That's odd... I googled heat transfer and they told me to come back later. |
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BTW, if the filament is small enough, then quantum mechanics provides adequate resistance to prevent the transmission of a single quantum of energy. Like bottleneck |
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Do this: Take two permanent magnets and put one on a surface. Make a few walls around it, and drop the second magnet in the walls, with the poles facing the opposite direction. Observe how it floats. Once I had this book of magnets information and tricks. You could make a pencil float with donut magnets. |
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I see, a single use thermos. Not the useful consumer item that I was envisioning. |
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I know truck drivers who've claimed that a run-of-the-mill stainless steel, double wall vacuum insulated thermos will keep coffee piping hot for two days if it's unopened. |
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//keep coffee piping hot for two days if
it's unopened//
This is
Schrodinger's Thermos. It keeps the
coffee both hot *and* cold until it it is
opened, whereupon the coffee collapses
into a tepid state. |
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DesertFox, I agree you can levitate something with magnets, but only if there is another constraining force (like the walls in your example [in your last annotation]). Since the point of your invention is to keep the inner container completely separated from the outer container, using magnets is pretty pointless. I suggest using an electromagnet with sensors/circuitry etc. to levitate the inner container. |
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Half, it is re-usable. Just reseale, and remove the air again. Suck the air out through the valve. See? It is the useful consumer item that you were envisioning. |
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xaviergisz, the magnets are then constraints for the other magnets. That is why they are placed as if on the faces of a cube. |
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Do you mean that you'd suck the air out with lung power to create the vacuum? |
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No, with a vacuum pump. :) |
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If you can get a small vacuum pump that attaches to the side, even better. |
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With sophisticated lids one could detach the top outer cup magnet allowing the inner cup to dock and lock with the outer lid. An inner part of the outer lid together with the inner lid could be opened for pouring without losing the vacuum. |
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It would work if the inner magnets were changed to superconductors, but then the tea would be a bit on the cold side. |
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[DF], I think that there is a small but fundamental flaw in your understanding of magnetism. Magnets do not "disallow contact". If you push two magnets together with sufficient force, you can overcome the repulsive force and put them into contact with each other. The force they exert increases as they approach one another, but does not tend to infinity as distance tends to zero. There's a maximum force a magnet can exert. |
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Not that that necessarily mitigates against this being a success, just that you've come up with a number of magnetics ideas, and I thought that making that point clear might be useful. |
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I know that. A large magnet, maybe about two inches across, and .5 inches thick, would probably suffice. If not, make it larger. Magnets can be pretty powerful, depending on it's compostition. I like magnets. |
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I can`t imagine a lid that, every time you un-seal and seal it, didn`t leak back air into the system. |
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Its a great idea for lousy coffee. My coffee doesn't last long enough to get cold, unless its from McD. |
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