Opinions on older HP80?

[Luis H]

I think Pete already provided links that explain tank threads, but here is also a good link:
http://www.diveriteexpress.com/library/valves.shtml

I think the outside diameter of the threads on a 3/4" NPS is a bit bigger than an inch (maybe 1.05"), but my machinery handbook and other references are at work.


The use of 7/8" UNF threads on a tank was IMHO a very bad idea and it is a good thing that they are not making them anymore. It is hard enough to service (inspect, tumble, etc.) the larger 3/4" NPS neck tanks.

My understanding is that only DIN valves are available for the 7/8" UNF necks. And sometime in the future even those valve may be hard to find.

A 3/4"NPS valve could be easily machined to fit the older 1/2" NPT (tapered pipe threads), but I don't know if the same type of valve could be machined for a 7/8" UNF threads. Even thought the 7/8" is smaller than the threads of the 3/4"NPS fitting it may not be small enough and the old threads may interfere with cutting new threads.

 

[Luis H]

Not to my knowledge and if there is a way to physically do it then it woulds not be on the up & up.

Pete

What the heck is: "on the up & up" ?

The valves are not regulated by the Scuba police.

 

[spectrum]

What the heck is: "on the up & up" ?

The valves are not regulated by the Scuba police.

Up & up: Kosher, proper, by the book.

Granted there is no scuba police but a yoke valve on a 3500 PSI cylinder should be enough to make a few dive shops pitch a fit.:11:

Pete

 

[Luis H]

Up & up: Kosher, proper, by the book.

Granted there is no scuba police but a yoke valve on a 3500 PSI cylinder should be enough to make a few dive shops pitch a fit.:11:

Pete

Hi Pete

So… now we have to consult with a Rabbi, Emily Post, and some kind of cockamamie book…what a PADI book?

Isn’t it is funny that the yoke fitting is now considered acceptable to 3442 psi but not to 3500 psi (less than 2% difference).


You remember seeing Ryan with this set of Cousteau / Calypso tanks? They were 5000 psi and look at the yoke fitting. Perhaps that valve system was probably not by the book either…there were no books… perhaps they wrote the books…not the PADI book…

For more interesting pictures of Cousteau equipment, this is a good website:
http://www.flashbackscuba.com/museum/New_Museum.html

 

[Scared Silly]

So… now we have to consult with a Rabbi, Emily Post, and some kind of cockamamie book…what a PADI book?

:ROTFLMAO

 

[Otter]

I believe 'the book' would be authored by the DOT, not any scuba agency. As for JMC diving 5000 PSI w/yoke, being from France the DOT would not have jurisdiction.

Also, consider that an HP80 filled to 3000/3500's capacity would only be ~68.5 cu ft.

 

[Luis H]

I believe 'the book' would be authored by the DOT, not any scuba agency. As for JMC diving 5000 PSI w/yoke, being from France the DOT would not have jurisdiction.

Also, consider that an HP80 filled to 3000/3500's capacity would only be ~68.5 cu ft.

If it wasn’t obvious, the mentioning of a PADI book and the Rabbi was a joke.

But, since you mention it, I am familiar with CFR 49 (Code of Federal Regulations, the codes used by the DOT) and I have never seen any mentioned of any type of fitting. CFR49 covers many types of pressure cylinders for many applications, including Scuba.

Fitting recommendations are normally covered by the Compress Gas Association. CFR 49 often invokes CGA documents, but I have never seen any reference on the CFR related to the connection fittings.


Oh… that tank systems above were JYC (Jacque-Yves Cousteau) and the Calypso team not JMC (Jean Michel Cousteau, the son of JYC).


Without getting into the yoke vs. DIN debate, it is well accepted that the yoke fitting can be used for up to 3442 psi. And, if you follow the codes, it can therefore operate at up to 11% above the working pressure when the tank is hot.

In any case, for the OP question about using yoke valves with that tank, the short answer it is doable, but probably impractical since an of the shelf valve is probably not available.

 

[spectrum]

If it wasn’t obvious, the mentioning of a PADI book and the Rabbi was a joke.

It sure gave me a good chuckle over breakfast.