If the world ran out of helium...

[Charlie99]

...in my 10 years of commercial oilfield diving I never used a hydrogen mix, though my deepsea days ended in 94'. Where have you heard such mix being used?

DSD

COMEX (the French company, not the commodity traders )did some experimental work with it in the '80s. In 1944 Zetterstrom went to 363' successfully, but died on the way back up from a 1945 dive to 528' when a winch operator brought his platform to the surface without stops. USN did some work in mid 70's. http://www.mejeme.com/dive/articles/mixhistory.htm has some of the history. A lot of exotic gases have been tried out commercially. Commercial companies have a lot of information on trials with exotic gases, but unfortunately most is not in the public domain.

 

[Gary D.]

I'd go with Methane Gas. Always available and I've always had some in reserve. Delivery is simple. Crack the valve a little for that slow gentle release or go wide open for the most rapid delivery.

They say it's hard to transport but I haven't had a problem taking it every where I go. It's never mistaken for say O2 or Helium because of its distinctive charictorics.

It can be stored in the original Mfg container, wet or dry suits, mini subs, planes, trains or automobiles. If there happens to be an accidental release people in the area would be warned by the alarm horn sounding. Many different tones are available should one be hard of hearing.

Great gas.
Gary D.

 

[DeepSeaDan]

COMEX (the French company, not the commodity traders )did some experimental work with it in the '80s. In 1944 Zetterstrom went to 363' successfully, but died on the way back up from a 1945 dive to 528' when a winch operator brought his platform to the surface without stops. USN did some work in mid 70's. http://www.mejeme.com/dive/articles/mixhistory.htm has some of the history. A lot of exotic gases have been tried out commercially. Commercial companies have a lot of information on trials with exotic gases, but unfortunately most is not in the public domain.

..that's all that good experimental stuff; in the field where the work is done, he. remains the gas of choice. Methinks they'd have kept at it ( experimenting ) if robotics hadn't progressed as it did; now, the impetus for VERY deep manned ops. is mostly a thing of the past....

DSD

 

[DeepSeaDan]

I'd go with Methane Gas. Always available and I've always had some in reserve. Delivery is simple. Crack the valve a little for that slow gentle release or go wide open for the most rapid delivery.

They say it's hard to transport but I haven't had a problem taking it every where I go. It's never mistaken for say O2 or Helium because of its distinctive charictorics.

It can be stored in the original Mfg container, wet or dry suits, mini subs, planes, trains or automobiles. If there happens to be an accidental release people in the area would be warned by the alarm horn sounding. Many different tones are available should one be hard of hearing.

Great gas.
Gary D.

...the cursed fart gas! The crapper used to be right the next tankage over from the living chamber in my saturation days. After a few weeks, the atmosphere got pretty ripe in there; and my god - HELIUM FARTS! Light, fast & deadly!

Thank the lord the pay was good.

DSD

 

[MBH]

Note to self; never do S-drills with Gary D.

 

[AbyssalPlains]

The reason for using only 4% O2 is that O2-H2 mixtures with more than 4 or 5% O2 are very explosive. So you will always need a travel gas.

Just out of curiosity - how can you sustain life functions on 4% O2?

 

[daniel f aleman]

How deep would I dive just on air? We may never know.

After all it only counts if you come back and can walk away from it.

Done 10,000 times a day world-wide.

 

[MBH]

Just out of curiosity - how can you sustain life functions on 4% O2?

With a hypoxic mixture. The 4% O2 will have a ppO2 of .21 at about 142ft.

 

[Charlie99]

Just out of curiosity - how can you sustain life functions on 4% O2?

Travel gas.

I'd use air to get down to 30-40 meters, and then 4% or 5% O2 + hydrogen mix (hydrox) from there.

and the rest of my post that you partially quote..

The reason for using only 4% O2 is that O2-H2 mixtures with more than 4 or 5% O2 are very explosive. So you will always need a travel gas.

You use air or some other mix with >18% O2 to get down to 40meter/130' range/5ata. At that 5ata pressure, even 4% O2 in a gas is enough -- the partial pressure of O2 is the same 0.2ata as is air at sea level.

 

[Gene_Hobbs]

Brauer RW (ed). Hydrogen as a Diving Gas. 33rd Undersea and Hyperbaric Medical Society Workshop. UHMS Publication Number 69(WS-HYD)3-1-87. Bethesda: Undersea and Hyperbaric Medical Society; 1985; 336 pages.
http://archive.rubicon-foundation.org/4862
--NOTE: this is a VERY Large file.

Work using hydrogen is still ongoing. Most recently, the use of bacterial flora to aid decompression has been looked at.

[SIZE=-1]Kayar and Fahlman. [/SIZE]Decompression sickness risk reduced by native intestinal flora in pigs after H2 dives. [SIZE=-1]Undersea Hyperb Med. 2001 Summer;28(2):89-97.
http://archive.rubicon-foundation.org/2373
[/SIZE]
Ball. Letter: Biochemical decompression of hydrogen by naturally occurring bacterial flora in pigs: what are the implications for human hydrogen diving? [SIZE=-1]Undersea Hyperb Med. 2001 Summer;28(2):55-6.
http://archive.rubicon-foundation.org/2421
[/SIZE]