Breathe Under Water Without Oxygen Tanks

Charlie Paglee writes "An Israeli inventor has developed a way for divers to breathe underwater without cumbersome oxygen tanks. His apparatus makes use of the air that is dissolved in water like the gills of a fish. With patents in Europe and the USA how long will it take for someone to use this to swim the English Channel underwater?"

Comments

Great!

[pomo monster]

Now you just need some batteries: "Calculations showed that a one kilo Lithium battery can provide a diver with about one hour of diving time."

Does that make it lighter or heavier than existing oxygen tanks?

Sounds to me like a job for nuclear-powered batteries.

Re:Great!

[david.given]

Does that make it lighter or heavier than existing oxygen tanks?

Actually, weight isn't an issue --- humans float, even with heavy steel tanks strapped to them, and you need lead weights to make yourself neutrally bouyant. You can get plastic air tanks, but nobody wants them: steel is more reliable and cheaper, and having lighter tanks means you have to wear more weights. Which are uncomfortable.

Oh, and divers very rarely breathe oxygen. (Unless you're counting the weird mixtures you use for very deep diving.) It's strictly compressed air, and is usually very dry compressed air to prevent rust in the tanks --- diving is one of the few activities where you can be under ten metres of water and still have a dry throat.

Amazing that someone didn't think of this before

[nganju]

Usually inventions only come about when the underlying technology is improved to the point where the new invention is feasible (i.e. made possible by faster processors, stronger steel, etc).

A look at the article reveals that the main components in this invention are a centrifuge to adjust pressure, and a battery to power said centrifuge. Both of these components have been around in usable form for decades at least.

Re:Not SCUBA

[jmv]

I don't see how the contraption can both be small and deliver at a high pressure while operating off of one battery.

Because you're already at that pressure, any device will produce O2 at that pressure. It would actually be *harder* to get it atmospheric pressure.

Also, now that I think about it, I think the US navy has some pure O2 underwater low depth breathing rigs like this.

I don't think anyone uses pure O2. When going past a certain dept, I think it's mainly a O2 + Helium mix, hence divers sounding like Donard Duck.

Ah, the questions...

[BinaryLobster]

What happens when you hit a patch of oxygen poor water? Better have some reserve oxygen in the design just in case.

Looks like your really trading an oxygen limit for a battery limit.

A centrifuge. Ah, wonder what the trade off is between swimming with a heavy tank and swimming with a spinning mass are like. Hope the moment of inertia isn't too big.

Wonder what other gasses you'll be collecting from the ocean along with your oxygen. Might not want to use this baby around any volcanic vents and such.

Re:Ah, the questions...

[Java Ape]

Yeah - or venture into any little anoxic pockets! Seriously, many marine environments (and a few freshwater lakes) have hypersaline sinks on the sea floor.

We used to detect these while diving because you "bounce" off of the superdense water if you're neutrally bouyant, and you can see the optical distortions caused by the density difference.

These little sinks can be fun to explore, since they often have extremely well-preserved stuff in them. However, they tend to be not only anoxic, but saturated with hydrogen sulfide (which is pretty toxic) and very alkaline (which eats up things like rubber seals, exposed skin etc). Wearing this device into such an environment would be fatal.

Re:Not SCUBA

[Jonathan_S]

What you have apparently neglected to consider is that the reason that "the bends" are an issue is that it is difficult to carry enough O2 to decompress on the way up.

If you had essentially unlimited O2, then you could stay deeper for longer, and do proper decompression on the way up.

As for the pressure, the air is dissolved in the water, and hence is *already* at the same pressure as the water itself. No additional pressurization necessary.

Except that recreational SCUBA diving, like the grandparent post is referring to, is designed to avoid a decompression stage; both because it is an easy thing for recreational divers to forget to do / skimp on, and because it affects the ability to deal with any emergencies that might arise while underwater.

It's safer if you maintain a dive profile that always allows you to return straight to the surface.

So the fact that this device could allow you to maintain at 30 or 60 feet for the 30+ minutes it might take to safely decompress on the way up isn't likely to change the rules for recreational diving.

Now it may be a big advantage for commercial or military diving where the divers are professionals and are willing and able to do dives that require mandatory decompression stops..

Disagree, think it could find a hold in rec diving

[SuperKendall]

Except that recreational SCUBA diving, like the grandparent post is referring to, is designed to avoid a decompression stage; both because it is an easy thing for recreational divers to forget to do / skimp on, and because it affects the ability to deal with any emergencies that might arise while underwater.

While that is true I still think it will find purchase in recreational diving.

The concern about casual divers running out of air is a big part of choosing a no-decomp dive for everyone, and for semi-advanced groups you could arrange a nice dive that went deeper for a while, then shallower for a while, until they could go back up.

Another major benefit is no more problems with heavy breathers which can terminate a dive early and really throw off plans of a dive group, which is another reason I think it will be quickly adopted even if it's not used for longer dives. It finally lets people dive as long as they are supposed to without tank capacity being a limit.

And yes, on some of my first dives I was one of those people that chewed through air way too quickly. It came from trying to also do underwater photography right off the bat before I was comfortable with boyancy and as a result I used a lot of energy (and thus air) maintaining depth. I don't make that mistake anymore!

For all those worried about oxygen toxicity:

[geekyMD]

You don't really have to worry about the divers breathing pure oxygen. They won't be. They'll be breating a mix similar to air.

The process of lowering the pressure around the seawater will lead to the release of all disolved gasses, not just oxygen. I didn't notice anything about a co2 scrubber, so I think its safe to say that the inhaled gasses will be similar in content to whatever is disolved in the ocean.

At atmospheric level, air is: ~73% nitrogen, ~23% oxygen, ~2% carbon dioxide, ~2% other, if I recall correctly, and I don't think that the solubility constants are signifigantly different in salt water to throw off those percentages that much. If anything its probably less rich in oxygen and more carbon dioxide enriched at greater depths due to marine life respiration.

With a system like this, it might even be possible to remove some of the nitrogen from the breathing mix with a second step. This would allow unlimited dive times without the nitrogen buildup that results in the bends if you stay down too long.