DEMA - Pressed Steel new tanks?

[Scuba]

metridium once bubbled...

So a 104 is a 106, but only if it's overfilled, and a 140 is actually a 135?

Would it really kill marketing to call a spade a spade?

Let's see,
LP 104 is the name of the tank What made you think it was the rated capacity - Fooled Ya. :haha: Don't complain its 106.2.
LP 140 is actually 135. Gottcha again :haha: Its payback time. :angry:

If the 140 will in fact be 135, not only is PST joining the crowd, but they will probably be leading it. Anyone know of a larger discrepancy?

Gotta go now, need to go fill my 80 to 78.2. That is, if the shop has'nt interpret it to mean 74.6.

 

[pescador775]

Wow! The E140 holds as much air as an old set of double 70's (@2250 psi). Of course, 'tech' divers will shun the new tank because they only believe in 'low pressure' tanks. LOL

 

[Genesis]

The "new" LP104 is ~130 cubes at its "higher" service pressure.

It also is a beast, being a 45lb monster with an 8" circumference.

The HP120 is 2" longer, but 7.25" around (instead of 8") and 9 lbs LIGHTER. In a twinset that's significant. Whether it will hose you in terms of getting in the way of your legs and such, or play hell with your trim, is another matter.

The LP80, IF they re-rated THAT one, would be a reasonable comparison to the HP100. But wait - why bother - when you can just fill the HP100 to anywhere between 2640 and the 3500 PSI rating and get the same tank volume. In fact, looking at the specs the HP100 and LP80 are pretty close...

I had three guys on my boat diving with me this weekend that all had HP100s and 120s.

The 120s didn't look THAT much longer than the AL80s that I'm used to. Its a 2" difference, and not much heavier either. The HP100 is SHORTER than the AL80, lighter when one considers the buoyancy shift differences, and carries 25% more air.

I was outbreathing one of the guys with a 120 with my AL80s (he was shocked!) - if I went to HP100s I'd be WAY ahead of them, and would also make my "call the dive" time pretty much always a matter of bottom time rather than gas supply. Of course then I have to be careful who I choose as a buddy, lest I end up on the boat with a LOT of gas left every time!

I could also double them up pretty easily, or get a modular valve assembly so I can run "H" valves on a single.

I'm getting less impressed with the LP104 idea the more I see of the various tank options in real life, on real diver's backs.

 

[C_C]

Ok folks, here is the skinny straight from the PST DEMA Catalog with my commentary to follow:

"PST Scuba introduces our latest scuba cylinder design called the E-series. The first scuba cylinder with a service pressure of 3442 psi to have a yoke/DIN valve capability. The E-Series incorporates our advanced cylinder technology found in our highly demanded AquaAire Sports Series. (C_C added note--E9791 HP cylinders)

The E-series combination of features can (sic) not be found in any other scuba cylinder. This cylinder offers excellent weight to volume ration benefits, and also has excellent size to volume ration benefits, plus negatively buoyant when empty, A design that when filled to 3442 psi will offer a diver a cylinder smaller than any other cylinder available. This same cylinder can be filled to lower fill pressures and still offer a diver a cylinder with great diving characteristics.

The new NRX valve offered on the E-series has a dual outlet capability. The valve can be used with either a yoke style regulator or a DIN style regulator. This valve is cleaned to CGA guidelines G-4.1 and can be used for nitrox gases.

The New E-series with sizes ranging from 52 to 149 cubic feet of gas with meet the needs of the beginning diver to the most advanced technical diver."

Ok...here is my commentary then on to the specs....These pressure ratings will apply only to NEW cylinders that are manufactured using the DOT Exemption E9791. This is the same DOT exemption that allowed PST to produce the HP 80, HP 100, and HP 120. This pressure rating will NOT apply to any cylinders produced under the DOT 3AA certification....this means no LP cylinders will/or can be rerated to the higher service pressure. To create the new service pressure cylinders, PST will use cylinder sizes similar to previous LP cylinders, but use E9791 alloy for the cylinder.


Examples include: E7-80 has size specs similar to those of LP 65s. Length is 19.75 inches, Diameter is 7.3 inches, Weight is 26 lbs without the valve and will hold 64 cf of gas at 2640psi, 72 cf of gas at 3000 psi, and 80 cf of gas at 3442 psi.

Here is a table of specs for each of the new cylinders:

Part # DOT Servise Water Water Diameter Length Weight Bouy Empty/Full
Spec Pressure Capacity Capacity Inches Inches Lbs. Lbs.
Cu. Inches Cu. Liters

E7-65 E9791 3442 psi 506 8.29 7.3 16.75 23.2 -1.5 / -6.4
E7-80 E9791 3442 psi 622 10.19 7.3 19.75 26.0 -1.5 / -7.5
E7-100 E9791 3442 psi 778 12.75 7.3 24.00 32.0 -1.3 / -8.8
E7-120 E9791 3442 psi 933 15.29 7.3 28.00 36.6 -1.3 / -10.3
E8-119 E9791 3442 psi 926 15.17 8.0 24.00 39.3 -0.5 / -9.5
E8-130 E9791 3442 psi 1013 16.60 8.0 25.56 42.2 -1.8 / -11.55
E8-149 E9791 3442 psi 1158 18.97 8.0 29.37 47.5 -1.8 / -12.9
LP-45 3AA 2640 psi 440 7.21 5.5 23.00 18.0 -0.5 / -3.9
LP-80 3AA 2640 psi 785 12.86 7.3 24.00 32.00 -1.0 / -7.0
MP-72 3AA 3300 psi 572 9.37 6.9 20.75 32.00 -6.0 / -11.4


Valves and Manifolds being sold with PST cylinders will be those manufactured/marketed by THERMO.

In case the table does not tranlate well, attached is the same message in MS Word as a text (.txt) document

Any Questions???

C_C

 

[roakey]

Are they ceasing production of the current LP cylinders?

Roak

 

[Genesis]

The top "E7" tanks ARE the Sport series, from what I can see, or at least are so close as to be indistinguishable in terms of reality.

The bottom E8 tanks are the "new" ones.

The E8-119 is the old LP95 in terms of size. The 130 is the old LP104, and the 149 is the LP120 (in terms of size, again)

The issue of mass still stands though. The 8" .vs. 7.25" cylinder requires more material, it appears, in order to maintain the desired buoyancy characteristic (and perhaps meet pressure specs as well.) As such they're quite a bit heavier.

The only issue would be, I'd think, one of length. Can you deal with the taller cylinder - for shorter divers I'm sure it would be an issue, but it is, in all seriousness, only about a 2" difference over that of an AL80, having them side-by-side in my tank racks. For a "guy diver" - the "average" 5-11 to 6' guy - is it material? I don't know.

Basically, it looks to me like PST has essentially eradicated the reason for the "LP" cylinder, in that they are all "HP" now in reality, and the choice comes down to a 7.25" or an 8" cylinder, with the corresponding difference in length and mass - with the edge in length going to the 8", and a rather considerable edge in mass going to the 7.25" one.

The question of cost remains open, of course; is PST going to play games with pricing (either up or down) with these?

BTW, the DIN valves on the existing SPORT series are made by Thermo.

Roak - why would they bother continuing with the 3AAs? There's no difference that I can see between the new E8s and the old 3AAs in terms of mass or size.

 

[pescador775]

PST has finally done it right. They've moved away from the peculiar 7/8-14 neck size and standardized the large neck making vis and valve interchangability much easier. If they had done this 10 years ago, I wouldn't have been forced to re-machine several yoke valves to 7/8" (don't ask). I'm happy with my 100hp's, so what the heck.

Genesis, you seem like a smart guy. How how you survived this board so long?

To answer your speculation; yes, wall thickness must increase with tank diameter, engineering rule.

CC: you have been a big help keeping us informed of this interesting development. BTW, why the 'sic'--- can not vs cannot? Picky, picky (G).

 

[C_C]

"The E-Series combination of features not be found in any other scuba cylinder."

Not picky...just trying to be helpful.

A version of the table that is easier to read can be viewed at:

http://diverlink.com/forum/uploads/1_pst.htm

C_C

 

[Genesis]

Do we know that the new tanks will (all) have the 3/4" threads?

Or are they keeping the other threads for their "sport" series?

I didn't see THAT in their release....

 

[pescador775]

CC, the table is excellent. However, there appears to be an error in the data for E7120. The numbers for length and dia are probably 28 X 7.3 vice 28 X 8.0. Looks like a transposition typo from your post above. Picky, picky