Help Identifying Steel Tank

[rsingler]

Lucky you!
You can now fill to 110% of the rated pressure of 2250, or 2475 psi. That gives you the rated capacity, of 71.?? cu ft.
Hang on to that hydro shop! It's uncommon to find one that will "+" rate a tank without a REE number, which gives the hydro shop the data it needs to confirm +10% capability during hydro.

EDIT: Lol, rjack beat me to it.

 

[runsongas]

it is possible the hydro tester took the time to calculate the REE from the wall thickness.

 

[rhwestfall]

or, he knew from experience (already has the information on hand)......

 

[TectonicDrake]

So based on the height what do you guys think I have? lp80?

Looks like 28.5" from the bottom of the tank to the neck where the valve screws in and 7" diameter or slightly over I'm having to eyeball that a bit.

is it just me or is that really tall? what kind of odd ball size is this thing?

 

[ScubaBunga]

Norris seems to still be around, maybe they have old records - surprisingly for me, I haven't tried to contact them already for info on my tanks - or the pressed steel ones since it says they bought out PST in the 70's!

This link has enough info to make anyone's head hurt on the topic of Plus/ree, etc.
Questions about LP72 tanks

The neat math on the + is that you only get the defined volume if you have the +, otherwise you are 10% less. This math (I think) is in the link as well.

The link also has the pre-stretch procedure for old galvanized tanks if your hydro guy is not used to seeing older tanks. I think the doc is for PST tanks, but I would assume all 72 galvanized should probably use that method.

 

[TectonicDrake]

At this point, I'm pretty sure it's larger than a 72. based on everything I've found 72 Cu ft tanks are all around 7 inches in diameter and about 24 inches tall. I remeasured and I'm definitely 28 inches and some change. Just kinda want an idea of how much more air I have because I'm a stats nerd. Also, want to know more about its buoyancy characteristics without trial and error.

 

[2airishuman]

At this point, I'm pretty sure it's larger than a 72. based on everything I've found 72 Cu ft tanks are all around 7 inches in diameter and about 24 inches tall. I remeasured and I'm definitely 28 inches and some change. Just kinda want an idea of how much more air I have because I'm a stats nerd. Also, want to know more about its buoyancy characteristics without trial and error.

2250 PSI steel cylinders are neutral when empty with valve in salt water. There are only slight variations with size with cylinders smaller than 72 cf being somewhat more negative.

LP72s are 6.9" in diameter and 25" in overall height with the boot removed; they weigh 30 pounds empty with no valve. Some boots can add quite a bit of height.

It is difficult to measure height accurately. The best way is to put it flat on a kitchen counter with the bottom against the wall, block it in place, and then use a carpenter's square and a tape measure to get the length.

If it's really 28 inches it will hold about 85 cf. There were some oddball cylinders in that era so I suppose it's possible.

 

[TectonicDrake]

I'll bust out the real measurement tools tonight and let you know.

 

[rhwestfall]

If you want absolutes, time to pull the valve, and measure the amount of water it holds. Once you have that information, start over with it's internal condition.....

If you are depending on that much exactness, your dive plan is, IMHO, flawed.....

 

[TectonicDrake]

Nah this is just me wanting to know what I have. It passed hydo and viz inspection it works. I'm super happy. Just nice to say what I have when people ask. We also kinda compete to see who used the least air on a given dive as sort of a mini game. So it's only slightly more than idle curiosity That being said I'm 100% certain. Without the valve or boot that it's over 28 inches somewhere between 28.25 and 28.5