Tanks with two psi markings

[dead dog]

Has any one see tanks like these before ?

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Has two psi ratings one is 5000psi and the other is 3000 psi rating.
eBay Item # 200691816668

dead dog

 

[captain]

Not sure they are steel. They look like Navy aluminum 90 cu/ft tanks. They were specially made for the Navy by PST before aluminum tanks were in common use. I have a set and I am using them in my avatar picture . The markings are the service pressure, 3000 psi and the test pressure, 5000 psi. They are not DOT specification tanks and as such present some issues with hydro testing them but it can be done. Unless you can fill them yourself it is best to pass on them as most shops will not fill them.

 

[Culcuhain]

that gives me an idea how to mount doubles to one of the two backplates I have. Thanks!

 

[dead dog]

Not sure they are steel. They look like Navy aluminum 90 cu/ft tanks. They were specially made for the Navy by PST before aluminum tanks were in common use. I have a set and I am using them in my avatar picture . The markings are the service pressure, 3000 psi and the test pressure, 5000 psi. They are not DOT specification tanks and as such present some issues with hydro testing them but it can be done. Unless you can fill them yourself it is best to pass on them as most shops will not fill them.

Thought

Navy aluminum 90's had no neck to the tanks.​

 

[Leadking]

They are PST tanks. TP=Test Pressure 5/3 of 3000 is 5000. As said no DOT/ICC markings.

 

[Thalassamania]

I had about 40 of them in the dive locker, at some point, because of a Navy Safety Bulletin, I removed them all from service and condemned them. I do not recall the exact issue, but it was the same tank, the one with the rounded bottom.

 

[Gilldiver]

They were made from seamless pipe that was spun down at each end. As such, there is the threaded neck at one end and a open hole at the bottom which was filled by a plug. The problem is that this plug can have corrosion develop at the plug/pipe interface. When that happens, the plug can blow out.....................

 

[Thalassamania]

Now I remember, thanks.

 

[Scared Silly]

W.P. == Working pressure
T.P. == Test pressure

As said above the std. hydro test pressure is 5/3 of the working pressure.

 

[captain]

Thought

Navy aluminum 90's had no neck to the tanks.



​

The early 1/2" NPT thread valve tanks had no neck, later 3/4" straight thread valve tanks have a neck.