The idea of breathing underwater without cumbersome compressed air tanks has been the dream of science fiction writers for many years. In George Lucas movie "The Phantom Menace", Obi-Wan whips out a little Jedi underwater breathing apparatus and dives in. As things tend to happen in our world, yesterdays science fiction has turned into today's science fact due to one Israeli inventor with a dream.

There are a number of limitations to the existing compressed air tank underwater breathing method. The first is the amount of time a diver can stay underwater, which is the result of the compressed air tank capacity. Another limitation is the dependence on compressed air refueling facilities near the diving site which are costly to operate and are used to compress the gas into the tanks which might be dangerous if not handled properly. The final problem has to do with the actual use of compressed air tanks underwater. When these tanks are in use they empty out and change the balance of the diver in the water.

Engineers have tried to overcome these limitations for many years now. Nuclear submarines and the international space station use systems that generate Oxygen from water by performing 'Electrolysis', which is chemical separation of Oxygen from Hydrogen. These systems require very large amounts of energy to operate. For this reason, smaller, diesel fueled submarines cannot use these systems and are required to resurface to re-supply their air tanks every so often. Divers can't even consider carrying such large machines not to mention supplying them with energy. To overcome this limitation an Israeli inventor, Alon Bodner, turned to fish. Fish do not perform chemical separation of oxygen from water; instead they use the dissolved air that exists in the water in order to breathe. In the ocean the wind, waves and underwater currents help spread small amounts of air inside the water. Studies have shown that in a depth of 200m below the sea there is still about 1.5% of dissolved air. This might not sound like much but it is enough to allow both small and large fish to breathe comfortably underwater. Bodner's idea was to create an artificial system that will mimic the way fish use the air in the water thus allowing both smaller submarines and divers to get rid of the large, cumbersome compressed air tanks

The general structure of the system

The system developed by Bodner uses a well known physical law called the "Henry Law" which describes gas absorption in liquids. This law states that the amount of gas that can be dissolved in a liquid body is proportional to the pressure on the liquid body. The law works in both directionslowering the pressure will release more gas out of the liquid. This is done by a centrifuge which rotates rapidly thus creating under pressure inside a small sealed chamber containing sea water. The system will be powered by rechargeable batteries. Calculations showed that a one kilo Lithium battery can provide a diver with about one hour of diving time.

Bodner has already built and tested a laboratory model and he is on the path to building a full-scale prototype. Patents for the invention have already been granted in Europe and a similar one is currently pending examination in the U.S. Meetings have already been held with most major diving manufacturers as well as with the Israeli Navy. Initial financial support for the project has been given by Israel Ministry of Industry and Commerce and Bodner is currently looking for private investors to help complete his project.

Illustration photo - Maayan Shenhar

If everything goes according to plan, in a few years the new tankless breathing system will be operational and will be attached to a diver in the form of a vest that will enable him to stay underwater for a period of many hours.


Transcript of the Interview with Alon Bodner:

Question: We are speaking now with engineer Alon Bodner. First of all I have to tell you that since we put up your report on IsraCast, we have been inundated with literally millions of people going into our website to find out about your invention. Just where did you get the idea sir?

Bodner: My seven years old son, Aviv, asked me some questions about the possibility of diving without tanks, maybe he was inspired by a Star Wars' movie, and then the wheels in my head started spinning. I knew that there is dissolved air in the water and that the fish breath this air so I thought, with all the technology in the world, why couldn't we also do it?

Question: But just how practical is your idea, have you actually tried to run through this prototype in a pool or that kind of thing?

Bodner: I call it a lab model it's not yet a prototype, it's in an aquarium which has a pump, a centrifuge, some hoses and a balloon, we cannot take it into the water yet, into the sea, but we tried it out with water and we saw that in principle it works.

Question: In principle it works. We've been getting inquiries from people all around the world, some are asking what about the quantity, the large quantities of water that might have to be processed in order to get an adequate amount of oxygen for a diver?

Bodner: I want to distinguish between open diving systems and closed diving systems. Usually when you go sports diving it's with open systems and this means that you inhale air from a tank and you exhale it into the water, and this requires a very large quantity of air. With closed systems, such as with breathers for individual divers or submarines or maybe in the future underwater habitats, the required water flow is much smaller, so this device is very suitable.

Question: In other words, it could be a portable apparatus?

Bodner: It is supposed to be a portable apparatus, yes.

Question: And when you speak of underwater habitats, just what do you have in mind?

Bodner: Well right now there exists several underwater habitats especially for research, off the coast of Florida there is one. It's like a Spacelab in the past, in which a few scientists live 10-20 meters underwater, they breath from compressed tanks and perform experiments. In the future, you can have a whole city or many people under a glass dome and breathing air straight from this device.

Question: What about the scientific community, have you yourself been approached by scientists and so forth?

Bodner: Well I have, a few people do not understand the concept, they assume that I separate oxygen from the water and they say correctly that it is toxic below a depth of seven meters and then they ask some technical questions. In this case I want to say again, the device can extract air from the water. It is dissolved air which contains oxygen and nitrogen and so on. It does not extract oxygen from hydrogen.

Question: And what are some of the technical problems that you have to overcome at this stage?

Bodner: The main concerns are the power of the batteries I suppose and the water flow. The batteries are evolving in a very good rate and we don't expect any problems right now. As I said the water flow can be a problem, especially if using open systems, if you want I can elaborate better calculations.

Question: If you could, please.

Bodner: The calculation is quite different for open or closed systems; I'll start with the calculations for open systems. A diver can consume about 25 liters per minute of air at the surface. Assuming that there's about 2 percent of dissolved air in the water, the calculations show the water flow requirement of 1,250 liters per minute. As you go deeper your lungs require more air. At 10 meters depth the air and water flow requirement is double than that on the surface so that means that you will need 2,500 litters per minute of water, and this is a lot. For closed systems, the calculation is different. In these systems the air is re-circulated and returned to the diver after the carbon dioxide is removed. For this case we calculate the oxygen consumption rate and not the air consumption rate as before. Say a diver consumes one liter per minute of oxygen, and unlike the above calculation your body requires the same amount of oxygen at all depths. So, assume there is about half a percent of dissolved oxygen in the water, this result in the water flow requirement of only 200 liters per minute at all depths, which is not too bad, and we can make a compact machine for this.

Question: Engineer Bodner, you are a diver yourself?

Bodner: Yes, lately I dive mainly in the Red Sea in Eilat and in the Mediterranean Sea, in the past I also dived in the Bahamas and off California.

Question: So you can be a guinea pig for your own invention now?

Bodner: I'd love to, but there are also many other volunteers, I get lots of e-mail from people all over the world who want to volunteer, to be among the first to use the systems.

Question: OK, let's go to the big question now. How long do you estimate that it might take before your remarkable invention actually goes on the market, becomes marketable, in a finished product?

Bodner: I expect the complete work the complete working prototype in about two years; this is provided if I get more funding, a commercial product will be ready shortly thereafter.

Question: Well, what can we say, perhaps when the Wright brothers talked about people flying like birds in the air, you're following in their footsteps and talking about people that can swim like fish in the sea.

Bodner: Well I hope so but it's too early still to compare me with the Wright brothers but I appreciate the comparison.

Question: Have you had approaches from manufacturing companies and so forth?

Bodner: I have but the discussions are still at early stages so of course I cannot divulge which names I'm speaking to.

Iddo Genuth, Tomer Yaffe - IsraCast, Jerusalem

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Comments (6):
  1. Consultor NETWORKS.
    Miguel Lopez, Mexico City 01 55 53835056 -- Jul 13, 2007


    p.d. In the house of my father exist many morades I go to prepare one


  2. Splendido
    mario luosi, Pensionato -- Jul 28, 2007

    Non ho parole,sarebbe meraviglioso averlo già domani. Passerei le giornate a fotografare i fondali del mare.

  3. Mr
    Salvo, Petersfield, UK -- Aug 14, 2007


  4. i wonderd the size and shape and price (if they are for sale)
    daire , skerries , co dublin i. ireland -- Aug 14, 2007

    hi i was thinking earler it would be cool to breath underwater at local swiming pools for ages and ages so i was in a hurry didnt get to read the whole articale so i was wondering if these respiratry things are for sale and there approximate price in euro

  5. ideale per il nuoto pinnato!
    silvia bugnoli, ravenna -- Aug 25, 2007

    Sono l'allenatrice di una squadra di nuoto pinnato, uno sport forse sconosciuto ai più che si pratica con la monopinna e una delle specialità di questo sport è proprio la velocità subacquea che si pratica con bombole ed erogatori. Questa specialità purtroppo sta morendo a causa sia dei costi di ricarica delle bombole sia per la pericolosità delle bombole ad aria compressa. Aspetto quindi con ansia che questa novità entri sul mercato perchè permetterebbe di azzerare i costi di ricarica delle bombole e, dal momento che le nostre gare durano al massimo 10 minuti, spero che le batterie non si dovranno cambiare così spesso! Ciò potrebbe far rifiorire una specialità affascinante come quella della velocità underwater e gli atleti potrebbero allenarsi tutti i giorni senza pericoli e con costi limitati. Buon Lavoro!!!

  6. no
    no, no -- Sep 07, 2007

    popular mechanics had a article bout this

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