Oxygen Clean Tank

[royalediver]

DOT does have authority, they approve every scuba cylinder in the U.S.-try making your own.

 

[royalediver]

Hmm... so it seems like very slowly bringing the pressure up would at least reduce the risk of this occuring.

I couldn't find the ignition temperature of aluminum plate or rod (only powder), but I found the melting temperature of aluminum sheet to be 1220F. I would imagine that it probably has to melt before it can burn, since evaporation is much easier than sublimation, and combustion can only occur in the gas phase. But that doesn't seem to be unreasonable temperature to have in a localized combustion area inside a tank with a few hundred PSI of O2.

If you all are the guys that "wrote the book" on this stuff, then I guess I am not going to bash heads with you. But, again, I would like to see documented instances (such as a fire inspector's report) of SCUBA cylinder failure due to oxygen fire. And not when the user is compressing O2, only a transfill. As authorities on the subject, you should be able to give this information.

Ask the woman who died in Luraville when an oxygen fire started in the small pony she was filling.

As to aluminum burning read up on the HMS Sheffield

 

[in_cavediver]

DOT does have authority, they approve every scuba cylinder in the U.S.-try making your own.

Actually, if so inclined, you could. You just couldn't use them in commerce. (at least interstate commerce, OSHA would likely keep the intrastate stuff as well). Dive shops wouldn't fill them etc etc.

So, if you have a large cold drawing press, you know, the one you picked up when PST went out, by all means, make your own. Oh wait, nobody really has the capability to make large high pressure vessels economically. Moot point.

Still, technically, DOT doesn't have regulatory oversight for personal cylinders and unless you interact with commercial entites, Hydro's aren't requried either. VIP and O2 cleaning is a scuba industry thing only.

 

[oxyhacker]

Actually, people have made their own. It's perfectly legal. And there are a lot of US divers, RBers especially, who regularly use commercially manufacturered, but non-DOT, tanks.

The way I usually explain it is that, while the DOT doesn't have jurisdiction (most of the time) over privately owned scuba tanks, it makes sense for everyone to pretend it does.

DOT does have authority, they approve every scuba cylinder in the U.S.-try making your own.

 

[Thalassamania]

DOT does have authority, they approve every scuba cylinder in the U.S.-try making your own.

They have no authority to tell a private citizen what to do with a scuba tank, that is an "industry standard," nothing more.

 

[robzr]

About the Diesel fuel: Diesel fuel will not normally ignite at high pressures. Fuel ignites in a Diesel engine because of heat generated by almost instantaneous compression of the air-fuel mixture, correctly referred by another poster as "stoichiometric". In cold weather, additional means are needed to ignite Diesel fuel.

Carbon monoxide is not a typical byproduct of combustion in an oxygen environment.

Aluminum cylinders will always be suspect for the purpose of containing oxygen. They should be cleaned more frequently than steel. The main danger is possible presence of loose particles of metal.

The word "adiabatic" is most frequently used by those who have no clue.

I think "stoichiometric" as in the stoichiometric ratio that car guys are always talking about, actually refers to the ideal ratio of oxidizer:fuel, example being the approx 14:1 ratio by weight of air to gasoline... running rich would be on the low side of this ratio and lean on the high side - it's the ideal ratio for combustion, ie, there is no leftover of either part when it's done.

Adiabatic heating is the process in which a gas heats up as it gets compressed, as expressed by Charles Law V(1) / T(1) = V(2) / T(2), temperature varies in proportion to pressure.

If I remember from my VIP class correctly isn't the main problem w/ using a dirty tank with O2 being that the friction from gas moving (not the adiabatic heating) can burn the hydrocarbons and generate CO, which can poison the diver?

Rob