3000 psi STEEL PST cylinder?

[Colliam7]

A customer gave our shop an older PST steel cylinder, working pressure 3000 psi. It is approximately 7” in diameter, and appears to be a little shorter than a HP 100.

I have not seen one of these cylinders before, and cannot find any information on it (e.g. capacity at working pressure, years of production, etc). However, I did find that a SB user sold one of these through the SB Classifieds, about 4 years ago. That user posted a picture of his cylinder. Our cylinder looks the same, with the exception of a later (higher) serial number, and a later ‘birth’ date (original hydro date), 1984 in our case. 3000 psi PST steel tanks 94cf? Galvanized and very nice.

If anyone knows anything about this particular line of PST cylinders, I would love to hear from you. I am going to determine the internal volume of the cylinder, and try to back calculate to capacity, at 3000 psi. I will dive it, to get a feel for its buoyancy characteristics. But, I would love to know more, if there is information out there.

 

[cfoster]

I have a pair of these from about '79 that I just got back from hydro. They would be 94.6cf if they were filled to the + rating with 3300 psi. I believe they sit somewhere between 85cf and 88cf with a 3000psi fill. They are very heavy and very negatively buoyant.

 

[2airishuman]

I have one also that I just purchased from another SB member. It is in my "to be hydro'ed" pile.

Specs:

3AA3000
Original hydro 1/79
42 lbs empty (with valve)
Buoyancy empty -10.2 lbs (with valve in fresh water. I measured)
Neck threads 3/4 NPSM
Galvanized finish
Serial # 16899V

Nominal capacity is usually given as 94-96 cubic feet.

These cylinders have roughly the same exterior dimensions as an LP85 but have a thicker wall.

The empty weight is comparable to a PST HP120 (41 pounds) or Worthington X7-120 (43 pounds).

 

[Kobusdan]

A customer gave our shop an older PST steel cylinder, working pressure 3000 psi. It is approximately 7” in diameter, and appears to be a little shorter than a HP 100.

I have not seen one of these cylinders before, and cannot find any information on it (e.g. capacity at working pressure, years of production, etc). However, I did find that a SB user sold one of these through the SB Classifieds, about 4 years ago. That user posted a picture of his cylinder. Our cylinder looks the same, with the exception of a later (higher) serial number, and a later ‘birth’ date (original hydro date), 1984 in our case. 3000 psi PST steel tanks 94cf? Galvanized and very nice.

If anyone knows anything about this particular line of PST cylinders, I would love to hear from you. I am going to determine the internal volume of the cylinder, and try to back calculate to capacity, at 3000 psi. I will dive it, to get a feel for its buoyancy characteristics. But, I would love to know more, if there is information out there.

Did you ever get any more information on this?

 

[happy-diver]

Hello thanks what's happening

 

[al248005]

Did you ever get any more information on this?

I actually have a set of these doubled up for my girlfriend. Lots of gas and not super huge! Everyone I show them to they all scratch their heads when I say they are 3000 psi. From what I heard they were only made for a few years and was told they are 3000 psi because they were made before HP and LP existed.

 

[Scared Silly]

I actually have a set of these doubled up for my girlfriend. Lots of gas and not super huge! Everyone I show them to they all scratch their heads when I say they are 3000 psi. From what I heard they were only made for a few years and was told they are 3000 psi because they were made before HP and LP existed.

If the specs @2airishuman provided are correct, doubled they are !@#$% heavy on land and !@#$% negatively buoyant. No way would I dive them. IMHO MP cylinders are not good cylinders to double.

 

[al248005]

If the specs @2airishuman provided are correct, doubled they are !@#$% heavy on land and !@#$% negatively buoyant. No way would I dive them. IMHO MP cylinders are not good cylinders to double.

I havent weighed them yet but plan to once I get them filled again. They are definitely lighter than my Faber 108s. Those things are a beast so anything is lighter.

 

[Scared Silly]

They may be slightly lighter on land than LP108s but I would be more concerned with buoyancy. Faber LP108 are approximately -5 lbs when full. The MP95s are -10 lbs empty. That is -17 lbs when full!! Doubled is -34 lbs!! NFW would I dive those even in a drysuit and redundant floatation. Get some Faber LP95s.