Posted on 07/04/2005 10:29:15 AM PDT by nickcarraway
AN ARTIFICIAL gill that mimics the way fish breathe could allow divers to dispense with bulky oxygen tanks, it was claimed yesterday.
The device, which has been developed by an Israeli engineer, could also be used to supply air to submarines and underwater hotels.
Fish gills filter water to remove small quantities of dissolved air.
The device, which was designed by Alan Bodner, consists of a lightweight cylinder containing a centrifuge.
Water passing through the device is rapidly spun and thrown to the outside of the cylinder, leaving a vacuum in the middle. The drop in pressure releases dissolved air, which is collected.
Not only can the device help divers to breathe but it may also provide a form of jet propulsion, according to Mr Bodner.
"The diver will be able to adjust the directions of the intake and out-take vents to use the flow as a propulsion method in a similar way to a Harrier jet," he told the Engineer magazine.
The invention has already attracted interest from the Israeli navy, as well as from diving equipment manufacturers.
Oxygen tanks are the biggest limitation to the amount of time a diver can stay underwater.
As the tanks empty, they also change the diver's balance and this makes it harder for them to control their movements.
Recharging tanks with oxygen also takes time and is costly.
Nuclear submarines use electrolysis - a process of splitting water into its oxygen and hydrogen components using electricity - but this requires large amounts of energy.
Currently, Mr Bodner's device is powered by a one-kilo lithium battery providing a diving time of about an hour. He hopes to extend this to several hours, however.
The "gill" is best suited to closed-circuit diving, where exhaled air is continuously recycled by cleansing it of carbon dioxide and adding oxygen.
In conventional open- circuit diving, exhaled air is vented into the water. This process, however, consumes a much greater amount of air.
To operate in this way, Mr Bodner's device would have to extract air from large volumes of water.
Interesting, but the line about as tanks empty, it changes the balance? Never happened to me, any change in weight is neglible and a good diver constantly adjusts his buoyancy throughout the dive.
While this device seperates oxygen from the water, you can't dive and breathe pure oxygen, under pressure the high level of oxygen will cause seizures. You need another gas mixed in (preferrably an inert gas that can't be absorbed by tissue).
has he built one yet? Someone I know did the math and said that it couldn't possibly extract enough oxygen without propelling the user very, very fast, or else be way too big to wear. There just isn't enough oxygen dissoved in water.
interesting, if not yet proven in the field
yet, somehow, highly active endothermic fish such as large sharks manage the trick
I assume John Innes is a science writer. He should know better. Whether we discuss a "vacuum" cleaner, an airfoil on a 777, a giant sution cup to handle glass or an artificial gill we are dealing with reduced pressure, not a vacuum.
Does it matter in a larger scheme of things what it's called?
Only if a better undestanding of science by the average person has a larger value to society than as just trivia.
The normal atmospheric pressure, of which we are unaware is 14.7 pounds per square inch. A difference of only one pound per square inch acting on a one square foot surface can overwhelm the average human being.
But a "vacuum", it's not.
So now we can look forward to an "Aquaman" movie.
This device is a cavitator - Ok, it pulls AIR out of the water. Something has to drive the centrifuge, elecricity? And I am going to be hauling a batter around? and if after 25 minutes at 95 feet I get a power failure? Hmmm...better haul a pony bottle along with my big battery.
..the idea of a big bottle of air doesn't seem so bad.
Say, I've seen that before, wasn't that titled,
Sex Slaves of the Nautilus ? or was that Deep Jaws?
anyone who dives deeper from the surface than one lungful of air will allow him to traverse is... well "an idiot" springs to mind, but that is too harsh :)
the article did amuse me when complaining that electrolysis requires a great deal of energy... when talking about a military nuclear powerplant.
What's held in scuba tanks is actually compressed air, not oxygen.
And as the tank empties, the balance is changed, albeit slightly - an aluminum 80cf tank goes from two pounds negatively buoyant to 4.5 pounds positively buoyant, for a change of 6.5 pounds, and a HP steel 95 goes from -15 to -7.5, a change of 7.5 pounds.
But won't a device such as this add to Ocean Warming? It certainly will deplete the Aqua Ozone Layer. Libs will never go for it...
There was a 1960s Russian film called Amphibian Man about a man genetically engineered to live underwater.
Doesn't cavitation also wear out the impeller pretty quickly?
"The first Nuclear bombs were very big also. These things will be adjusted in time. Don't throw the baby out with the bath water. In Columbus' day, they thought the world was flat."
Yes, but that's because they had not yet reached peak efficiency.
My acquaintances calculation was based on peak efficiency in extracting the amount of O2 dissolved in water.
I'm more of the kind that go on hope, chance, luck, and dreams. Your kind usually win. (smiling)
How does a fishes Gills WORK.?.
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