Tank ID Help

[mahjong]

I'm just back from a trip to Turkey where I dove in Kemer (Mediterranean) and Saros Bay (North Agean). In both places, a very short (~20") and fat (~8" diameter) 12L steel tank was used. These tanks were filled to ~200 BAR, though I don't know their rating (couldn't read the markings due to tight mesh covers). I had never seen these tanks before. They were made in either Germany or Italy (Cressi), according to the operator in Saros.

Can anyone tell me the size of these tanks in cubic feet, filled to 200 BAR? I would also like to know their exact dimensions in inches. I didn't have a tape measure, but my Scubapro cam band, threaded through a Scubapro plastic backpack, was just barely long enough to lock down one of these little tanks, which were made a bit thicker by mesh covers.

 

[Scared Silly]

Yes, I can but you have all in the information you need. As such, the exercise is left to the OP.

Hint: Americans measure their cylinders based on the amount of gas at 1atm whereas European measure it based the cylinder volume at its working pressure. Two multiplications and you have your answer.

 

[Danseur]

SS, you sure about that?

Last I checked, EU etc was liquid volume in Litres, and US/CA were gas volume at working pressure. AL80 has "80" (77.4) cubic feet at the working pressure of 3000psi here...

 

[mahjong]

I much prefer multiple choice quizzes.




QUOTE=Scared Silly;6407790]Yes, I can but you have all in the information you need. As such, the exercise is left to the OP.

Hint: Americans measure their cylinders based on the amount of gas at 1atm whereas European measure it based the cylinder volume at its working pressure. Two multiplications and you have your answer.[/QUOTE]

 

[Scared Silly]

SS, you sure about that?

Last I checked, EU etc was liquid volume in Litres, and US/CA were gas volume at working pressure. AL80 has "80" (77.4) cubic feet at the working pressure of 3000psi here...

Volume is volume - which has greater volume a liter of water or a liter of air? Kinda like which weighs more a pound of lead or a pound of feathers? Folks use "water capacity" because it is incompressible and easily measureable. It is a real pain to pour air out of a cylinder at 1 atm .

Americans say a cylinder contains 80 cuft whilst implying 1 atm along with the working pressure (3000psi). Which if I fill it to 3150 psi calcuating the resultant volume of gas is not easy.

Europeans give the cylinder capacity (12L) and the working pressure (200bar) which is much easer to figure how much gas you are going to have (albeit in liters) as it is one multiplication, capacity times pressure, 2400 liters for cylinder described by the OP. Converting liters to cuft is something a 5th grader can do.

 

[mala]

I'm just back from a trip to Turkey where I dove in Kemer (Mediterranean) and Saros Bay (North Agean). In both places, a very short (~20") and fat (~8" diameter) 12L steel tank was used. These tanks were filled to ~200 BAR, though I don't know their rating (couldn't read the markings due to tight mesh covers). I had never seen these tanks before. They were made in either Germany or Italy (Cressi), according to the operator in Saros.

Can anyone tell me the size of these tanks in cubic feet, filled to 200 BAR? I would also like to know their exact dimensions in inches. I didn't have a tape measure, but my Scubapro cam band, threaded through a Scubapro plastic backpack, was just barely long enough to lock down one of these little tanks, which were made a bit thicker by mesh covers.

sounds like it was a dumpy 12l.
working pressure is 232bar.

about 2800 lts when full.


americans rate there tank on volume of gas at working pressure.
so an ali80 has 77 cuft -obvious really.
if the pressure is low or they breathed it then its not an ali80 its something less.

europeans measure a tank by its internal volume in lts so its always the same and doesnt shrink during the dive.

so a 12 ltr tank carries 12 lts of gas and its only the pressure that varies.
multiply the pressure by the tank to get the usable gas.

12ltr dumpies are favorite single tanks for short people.


the most common are made by Faber.

 

[mahjong]

So filled to ~200 BAR these tanks hold about 85cuft of air. And filled to 232 BAR they hold almost 100cuft. Wow! Those are great tanks! I am short, so loved diving them. They trimmed out perfectly for me. Are they available in the US? I don't think I've ever seen one before.

 

[mala]

So filled to ~200 BAR these tanks hold about 85cuft of air. And filled to 232 BAR they hold almost 100cuft. Wow! Those are great tanks! I am short, so loved diving them. They trimmed out perfectly for me. Are they available in the US? I don't think I've ever seen one before.

they are common in europe.
dunno about the us.
the walls are quite thick so they are heavy and require less lead.
i prefer the tall 12lts as they are more streamlined in the water and you can use them as twins which you cant with the dumpies.

 

[mahjong]

Why can't you double up the dumpies? Is there not enough flat tank length for 11" bolt spacing? If they are 8" in diameter then that's not a problem for doubling.

We dove from shore at Saros. I carried a bunch of the dumpies up and down a rocky cliff. They aren't as light as one might think given their diminutive stature. However, they are quite a bit lighter than my Faber LP95s.

 

[Edward3c]

I'm just back from a trip to Turkey where I dove in Kemer (Mediterranean) and Saros Bay (North Agean). In both places, a very short (~20") and fat (~8" diameter) 12L steel tank was used. These tanks were filled to ~200 BAR, though I don't know their rating (couldn't read the markings due to tight mesh covers). I had never seen these tanks before. They were made in either Germany or Italy (Cressi), according to the operator in Saros.

Can anyone tell me the size of these tanks in cubic feet, filled to 200 BAR? I would also like to know their exact dimensions in inches. I didn't have a tape measure, but my Scubapro cam band, threaded through a Scubapro plastic backpack, was just barely long enough to lock down one of these little tanks, which were made a bit thicker by mesh covers.

At 200 Bar = 84.76 cu ft.
At 232 Bar = 98.32 cu ft.

Measuring the outside of a cylinder will not give you its internal volume unless you know the wall thickness. I have two cylinders 7in diameter, but one is 9.841 Lt the other 12 Lt, and its the shorter that has the bigger capacity.

Kind regards