300 bar tank

[JonW*Interspiro]

Hi Ron,

By exemption number, I believe you are asking for the DOT#. It is filed under DOT SP-14209. We currently make 2 twin cylinder packs. One is the larger capacity at 6.7 liters (140 cuft) and weighs 37.5 lbs fully charged minus the buoyancy compensating weight and the smaller is the 3.4 liters (72 cuft) and weighs 20.7 lbs fully charged minus the weight. The advantage to this is reduced weight on the divers back at 95% ready. Other advantages are a more streamlined profile increase kick and less drag as well and easier access to a confined space. Our system is a first of it's kind designed as a complete system much like an scba for the fire service. We base this on safety with the diver in mind.

 

[WD8CDH]

Hi Jon,

I am very familiar with the advantages of slim twin tanks ( see post #5 and others here: http://www.scubaboard.com/forums/tanks-valves-bands/286251-carbon-fiber-tanks.html ).

I assume the liters figure is per tank and the cuft figure is per set. What is the diameter and length of the individual tanks in those two sizes? What is the neck thread?

I see that DOT SP-14209 shows a design life of 48 years or greater but a service life of 15 years. Have you thought of having the exemption amended to a service life of 30 years? There is currently a precedence of 30 year service life on a few of the Special Permits for at least one of the SCBA series composite tanks from Luxfer.

 

[WD8CDH]

Do you sell tanks individually? I often dive slim triples with the third tank independent.

 

[JonW*Interspiro]

Not at this time and I am not sure of any plans in the future. The hardest part to conquer is the buoyancy factor, that is why we have them in the twins. The brass weight slides onto a post in between so that there is even distribution on the divers back. If they come up with something here for the US I will let you know.

BTW Ron, where are you located? I need help with a general consensus regarding or surface supply system and the application in commercial diving. Any info would be appreciated.

 

[WD8CDH]

Not at this time and I am not sure of any plans in the future. The hardest part to conquer is the buoyancy factor, that is why we have them in the twins. The brass weight slides onto a post in between so that there is even distribution on the divers back. If they come up with something here for the US I will let you know.

BTW Ron, where are you located? I need help with a general consensus regarding or surface supply system and the application in commercial diving. Any info would be appreciated.

Hi John,

Triples would just require 2 weights. At least that is how I did it with titanium tanks or my present set of 7000 series aluminum tanks.

I am located in NY now but I did most of my commercial diving in the Gulf, in the Midwest and in the Great Lakes. Personally, due to my use of unusual equipment (four AGA tanks (two twin sets) at the same time:shocked2:, 7000psi titanium tanks and rebreathers), I did very little surface supplied air.

A lot of the surface supplied air that I saw had inadequate bailout. Often the tiny Survivair doubles with only about 20cuft total capacity or nothing at all. I usually used double 30's or double 40's for bailout.

 

[JonW*Interspiro]

With regards to bailout, here is where we shine. We have a configuration for surface supply that enables you to use the FULL 72 cubic on you back as a bailout should something happen with the supply line or at the surface! This is much safer than a pony bottle and gives you ample time to return to the surface. Most people relate to it as a J valve on our manifold block, but it is a much better, reliable design. We have a rep in NY if you ever want to see the system in person. Let me know and I will get you his contact info.

 

[bacaruda]

Is there a reason most bottles are only 232 bar and not 300, Surely a 12ltr 300 bar will hold the more air than a 15ltr 232bar cylinder and would be more managable?


Cheers

Yes there is a reason. The physics of gas is linear up to around 240 bar, At more extreme pressure, it's getting more complicated. In a 300 cylinder, the last 30-40 isn't "worth as much" as the rest, and the pressure will drop fast when used. If your Dive-shop doesn't "top-off" your 300 bar tank you will seldom see more than 270 bar on the manometer after the bottle cools down after filling. A 12 liter 300 bar bottle will not contain 12x300=3600 litre of air, it will be more like 12x270= 3240 litre.
A 15 litre 232 bar bottle will in fact hold 15x232= 3480 litre or more (can safely be filled to 250 bar). So with 232 Bar equipment you will get more "air/kg tankweight" that you drag around. On a 300 bar tank you pay for pressure that you realy cant use.
12/300 and 15/232 has approx. the same weight, but 12/300 will be more negative in the water. the only advantage that I can see is the smaller diameter of the 12/300.
I dive a 10 litre 300bar, mainly becasue of the extra weight (don't need so much around my waist) and the shorter lenght compared to a 12/232.

 

[LouieLouie]

7, 10, 12 and 15L 300 bar tanks are available in Scandinavia. 10/300 singles and 7/300 doubles are by far the most common. I've been told the 12/300's are crap, as they are too short and heavy to trim out well. 15/300's are supposedly slightly better but far from good. Most people choose D7/300's instead.

 

[WD8CDH]

The 7L tank is a sweet size for doubles but in the US, we can't get them in either 300bar or even 232 bar. We can only get that size in 180 bar (2400psi +10%, 45cf).