h a l f b a k e r yPoint of hors d'oevre
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Have you ever been washing the dishes, and lifted an inverted glass part way out of the water, so that it lifts up, full of water?
I want a swimming pool like this.
I envision a Plexiglas cylinder, about ten to fifteen feet around, and reaching a good twenty feet higher than the surface
of the water.
What’s that? “You could never pump that volume of water up a tube that large”, you say?
Your right, you probably couldn’t, but submerging the entire thing before capping it off, it would make it possible to lift the whole amount in one go, with a good size crane.
“But 2fries” you say, “What if you swim up to the top of your above ground pool and run out of air?"
No problem. There is a four foot air bubble trapped at the top of the tube.
Ahhh, I see by the look in your eyes that you’re thinking that the trapped air will become stale and or skanky, and that there would be no way for a compressor or pump to recycle fresh air with that huge amount of water to be kept suspended.
Well, this would be the reason behind having a four foot bubble instead of a two foot or even one foot bubble.
At two foot mark, would be a valved ceiling, which would trap the lower volume of air while allowing the upper level to be recycled and maintain the air seal holding up all that water. The upper valves would then close, and the volume of air in the top chamber would be mixed with the bottom.
The only thing I can’t figure out is whether the water would create such a negative pressure in the trapped air as to make it impossible to breathe.
That and how far you would be able to surf away from your pool if the thing ever broke.
Sort of baked, on a small scale
http://www.halfbake..._20double_20glazing
Look at [gnormal]'s links to this idea - transparent plastic tubing, with goldfish swimming in them. [hippo, Oct 05 2004]
koy sphere
https://www.youtube...watch?v=qJprKL_24ZA
[pashute, Sep 01 2014]
This, but half filled with water
https://www.youtube...watch?v=QmjzHWIF61c
[pashute, Sep 01 2014]
The opposite of this
https://www.youtube...watch?v=M_Q1IrPRWdM
[pashute, Sep 01 2014]
[link]
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This is actually quite workable. I assume that you plan to fill the air bubble at the top with pure oxygen, otherwise the 5 psi atmosphere in it would not support human life, and you’d end up with a raft of dead bodies up there. But go ahead. Experiment. |
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I'll go get my trunks,it's bloody hot here at the moment. + |
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Um, no pressure issues or air-circulation issue need apply. You can swim above ground in just the same way as otters do at aquariums behind the glass. Think of a huge backyard pool with clear sides. Who needs the top closed off? |
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//the water would create such a negative pressure in the trapped air as to make it impossible to breathe// |
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Good question! I’ve been wreck diving and have found air pockets inside, but they were pressurized, not depressurized. |
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Bag the valved ceiling. Just have a vacuum pump constantly removing the air. Simultaneously, a float valve controls fresh compressed air bubbling in from below to maintain a constant water level. |
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Now google on "hypobaric hypoxia" and discover why some of the world's top athletes may be competing for pool time over at [-2fries] place. |
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//the water would create such a negative pressure in the trapped air as to make it impossible to breathe// |
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Probably. The atmosphere will support a column of water about 10m high. Build it higher and you'll get a partial vacuum at the top. I say partial because it will have water vapour in it. |
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With 20 ft of water in the tube, up (about 6m), the pressure at the top is only slightly less extreme than the top of Everest, i.e. only breathable with large amounts of training, fitness, and a couple of day's acclimatisation. |
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The idea with the valve is a non-starter. If you split off the top bit of air, you still need to replace it with air at the same low pressure. This would require a pump every bit as powerful as one that could cycle the air without using the valve. |
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Build it without the air bubble and I think you've got a goer. (+) |
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(hang on a mo) There is an easier way, though. If you have two pools, one built higher than the other you can run a tube from the bottom of the higher one under the surface of the lower one, pop it into the air and have the same visual effect. You'd still need heaps of lifeguards to police the underwater tube but could leave the raised tube open to air at the top. I wonder how thick the glass is going to have to be... |
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I'm with lumpy....why not just build an above-ground pool with clear sides? |
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Not complicated enough, krelnik. |
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[krelnik] This is not the same thing at all. What [2 fries] has created is a low pressure grotto. You can only enter from the bottom. Beautiful, but also quite deadly. If he went up another ten feet with it, the water would steam and boil at the top, and so would your blood, if you were foolish enough to swim all the way up. Actually, with a thirty foot tube, you would lose consciousness at about 20 feet up, and then bob like a cork to the top, where, dead, you would be vacuum boiled in ice cold water.
These are spectacular effects that simply cannot be achieved in a swimming pool! |
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Whadaya know, I just saw this idea baked on tonight’s episode of Fear Factor.
I think we are being monitored. |
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I love pluterday's description. Bun. |
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I don't know which way to vote, but what keeps you from falling out? |
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Bouyancy [crash], the only way *out* is into the pool itself. |
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Is the entire tube lifted out of the water? I'd imagine if this were a tube suspended a few feet over a more traditional pool, handles could be placed on the open lower rim, so a swimmer could just stick his head out upside down of the lower surface of water into the atmosphere. Also would pressure build as you swam down or as you swam up? Which way would your natural bouyancy pull you? |
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The entire capped off tube would be raised, drawing the water up with it. The lower end of the tube could not be raised above the surface of the water or all of the water held inside it would rush out.
I'm not sure about which way you would be drawn by the bouyancy, my gut tells me that as you swam higher than the level of the exterior pool, you would float downwards rather than up because the pressure would decrease as you swam higher. You should find neutral bouyancy somewhere slightly above water level I would think. |
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Re-readin [pluterday]'s anno has me second guessing that assumption now though. |
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//(hang on a mo) There is an easier way, though. If you have two pools, one built higher than the other you can run a tube from the bottom of the higher one under the surface of the lower one, pop it into the air and have the same visual effect. You'd still need heaps of lifeguards to police the underwater tube but could leave the raised tube open to air at the top. I wonder how thick the glass is going to have to be...// |
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I'm very confused by this anno. If you're saying what I think your saying, what will keep the tube from siphoning all the water out of the upper pool? |
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//I'm very confused by this anno. // |
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the water level stays the same in a single container regardless of the size of the vessel. i.e. of you have a 3 in cylinder attached at the bottom to a 2 in cylinder the water will be at the same height in both of them. as long as the tube extends above the water level of the tall pool, no water will be lost. |
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For structural strength, you would want the pool to be shaped like a hemisphere. This would also produce the most interesting optical effect. |
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And the easiest way to construct this idea would be as follows: |
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Start with a regular swimming pool. Construct, on that pool's floor, a support structure for the glass hemisphere, which holds the bottom edge of the glass exactly level with the water level of the regular pool, and the dome several feet above the regular pool's water level. |
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Connect a vacuum pump to the top of the hemisphere. Fill the lower pool in the normal manner. Activate the pump, and add more water to the lower pool while the pump is running. The pump will reduce the air pressure inside the dome, and the atmosphere will push down on the water in the lower pool, forcing it into the dome. |
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When people will be swimming in it, leave the vacuum pump running. Water from the lower pool will be pushed by the atmosphere into the dome, just as it does when is was being filled. However, since we aren't adding water to the lower pool, the water level in the lower pool will decrease. When the lower pool's level is low enough, air from the atmosphere will flow under the edge of the dome, displacing some water from within the dome back to the lower pool. |
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If the bubbles produced by that method are aesthetically displeasing, a glass or clear plastic tube could run from the air bubble in the dome, down along the surface of the dome, under the dome's lower edge, and (now outside the dome) up an inch or two to just below the lower pool's water level. Similar principles apply as before, but the air entering the dome will go through the tube to the air bubble. |
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That would actually work ... |
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look at the latest links. (That's what brought this up again) |
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Went to bun this, already had. |
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