Invention Allows Humans to Breathe Like Fish

[Dover]

Invention Allows Humans to Breathe Like Fish
By Bill Christensen

posted: 06 June 2005
09:07 am ET

Alan Izhar-Bodner, 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, just like fish do.


The system uses the "Henry Law" which states that the amount of gas that can be dissolved in a liquid is proportional to the pressure on the liquid. Raise the pressure - more gas can be dissolved in the liquid. Decrease the pressure - gas dissolved in the liquid releases the gas. This is exactly what happens when you open a can of soda; carbon dioxide gas is dissolved in the liquid and is under pressure in the can. Open the can, releasing the pressure, and the gas fizzes out.

Bodner's system apparently uses a centrifuge to lower pressure in part of a small amount of seawater taken into the system; dissolved gas is extracted. The patent abstract reads:

A self-contained open-circuit breathing apparatus for use within a body of water naturally containing dissolved air. The apparatus is adapted to provide breathable air. The apparatus comprises an inlet means for extracting a quantity of water from the body of water. It further comprises a separator for separating the dissolved air from the quantity of water, thereby obtaining the breathable air. The apparatus further comprises a first outlet means for expelling the separated water back into the body of water, and a second outlet means for removing the breathable air and supplying it for breathing. The air is supplied so as to enable it to be expelled back into the body of water after it has been breathed.
Human beings have been thinking about how to breathe underwater since they started swimming. This long-held desire plays an important part in one of the first great science fiction novels, Jules Verne's 20,000 Leagues Under the Sea.

http://www.livescience.com/scienceoffiction/050606_breathe_underwater.html

[MuseRider]

1. This is awesome!

I can't wait to be able to dive with something like that! No more compressed air, no more need for Nitrox if you dive a lot. So many benefits to a system like this. It will totally change diving. Thanks for posting this.

[lapfog_1]

2. My read of that short article doesn't lead to your conclusion

The extraction of gas from water (dissolved oxygen) happens
in a tank or cannister. Compressed air is still required to
equalize the air spaces within the body with pressure of the
column of water on top of the body... I can see how the dissolved
gas might be extracted, and maybe it can be delivered at ambient
pressure... but you still have the gas mixture issues and different
rates of absorption within tissues. It's unlikely that this
invention alone (even if it works) will be all that useful to the
scuba diver anytime soon. Not to say it can NEVER lead to a
"Aqua man" type system.

I'm curious as to how much power is needed to centrifuge the
water sufficiently to extract dissolved gasses... and whether or
not the diver using such a system might undergo "gyroscopic"
effect from carrying a spinning centrifuge around on his/her
back.

[MuseRider]

3. This article

http://www.isracast.com/tech_news/310505_tech.htm speaks a little more about it. I don't have time to read it again right now and last night it was very late when I did read it. It did speak of not needing compressed air and that it could be run on batteries but other than that I don't know.

[lapfog_1]

6. Hmmm... the process doesn't need compressed air to work

that's not what I was trying to communicate, rather poorly.

What I meant to say was...

Scuba divers will still need some sort of compressed gas in their
lungs and other air filled cavities to offset the water pressure
at depth. Which means that if this device works great (and we'll
assume it does), you still need a source of compressed gas to
keep from imploding (I've seen pictures of free divers taken
when they reach near human endurance... and it's something I would
never want to subject my body to).

Alternatively, one could fill the body cavities (lungs, nose, ear
canal) with a liquid (this has been done) which would still do
the oxygen / CO2 exhange...

[MuseRider]

7. My knowledge is

small. I dive, I love diving and go as much as a person in Kansas can go. At the depths of sport diving would compressed air really be needed? 130 feet is the max depth I believe for sport diving, maybe 135. I just don't know.

I do know about the filling of the body cavities with liquid and the very thought makes me shiver. I don't know how anyone could do that but they have.

[freethought]

4. Aside from how much power, how much water would you need?

This system isn't even out of the womb yet. The question I would have is how much water would the system have to take in in order to extract enough breathable air to remain submerged for a prolonged period? One SCUBA tank down about 20-30 feet may last 45-50 minutes depending on the individual, longer if your using NITROX.
How much water would have to be processed for the same amount of air?

I know there are recreational rebreathers out there (civilian versions of the gear the Navy SEALs use) but I believe they are very expensive, require special training, and maintenence is an absolute must. This could be a new alternative. Keep an eye out an see!

[Massacure]

5. Muserider's article says a 1 kilo battery (2.2 pounds) will last one hour.

It specificually mentioned lithium batteries. So that means 22 pounds of batteries will give you 10 hours of diving time. That isn't a lot of weight.

[MuseRider]

8. It seems to me

that it would have to circulate a LOT of water to get the amount of oxygen needed. Again, I have no clue about any of this.

[benburch]

9. Enough water...

that one could use the exhaust water for propulsion...

[oneighty]

10. A Semi-permeable membrane

Diving rig was developed many years ago. It failed to generate interest.

If this device is an open circuit breather it would require extracting about two-three liters per breath of dissolved atmospheric air to supply a hard working swimmer. This in turn would require many liters of water to be processed per breath.The exhausted water would indeed provide propulsion.

If however the device extracts only dissolved oxygen and the oxygen is used in a closed circuit diving rig it might work. But why bother?

Liquid breathing was performed on dogs many years ago as well.It required complicated mechanical pumps to ventilate the dogs with oxygen saturated saline. It proved impossible at the time to remove the carbon dioxide from the poor dog's system. Of seven dogs abused six survived and went on to finish their lives as pets. (So I like to believe. For certain one was. Her name was 'Princess').

But I would never say never.

180

[Billy Ruffian]

11. Don't forget about O2 toxicity

If it's extracting just O2, you'd be limited to 60 ft or so. Any deeper than 66 ft, and you're running 2 ATM partial pressure of O2, and begging for O2 toxicity. Convulsions would be a very bad thing to have at 60 ft. However, if the power supply could last a long time, this would let you stay underwater for quite a while .. remember, if you're on pure O2, you've got no decompression (no inert gas going into your bloodstream)

The water flow required to pull enough dissolved O2 out of seawater would require a heck of a lot of energy.

I can't fathom how this rig would weigh any less than a set of tanks,

Although it has been a while since I was a diver, I was a US Navy Deep Sea diver, qualified in air and mixed gas diving, and a variety of SCUBA and surface supplied rigs.

[benburch]

12. The gases dissolved in water include Nitrogen, too.

But not in the same concentrations as air.