Breathe Like a Fish

Here is another cool idea that I'd like to try out. It has to do with an Israeli inventor who has developed a system that may allow people to breathe underwater without tanks.

"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 tank capacity. Another limitation is the dependence on oxygen 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 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 electrical separation of hydrogen and oxygen from water. 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 airtanks 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 air tanks.

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 directions - lowering 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.""