hope someone can help with this, I'm looking to split an old 12ltr. steel twin set with the intention of side mounting them. I need to buy valves but can't find any measurements on the old valves. The only numbers that are stamped on are 0022. The measurements I've taken from the neck where they tread into the tank are 1 1/32 inch (26.2mm) and 14TPI. My reason for going side mount is there to heavy on land or I'm to old,
Tank valves needed
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Ordinary 3/4 14 straight thread,
Thermo Standalone Valve, Surplus | Dive Gear Express®
That's what I bought last time, but I'm guessing you'll have a more local option
Respectfully
James
Thermo Standalone Valve, Surplus | Dive Gear Express®
That's what I bought last time, but I'm guessing you'll have a more local option
Respectfully
James
No worries... Only other thing I just thought of, I've heard some of Europe uses a metric thread that is very similar, but I don't know enough about those to conclusively tell yours isn't metric.
Michael do you think I should scrape the paint of the neck of the cylinder to see if I can find some stamped measurements. Thanks
W W Meixner
Banned
Mac...
Certainly looks like a standard 3/4-14...I'm sure your LDS has lots of standard scrap valves that you can test fit...
Just don't force it...if it's standard 3/4-14...the valve will either thread right in or it won't...
Cylinder stampings North America don't include thread size...what you can check for is a Certification stamp/number...for use in the US its DOT...for Canada it's TC...determine what your certification requirement is for Ireland...if it does not have it...you will not be able to fill the cylinders commercially...either way the cylinders will need to be re-hydro'd...and current annual visual inspection...
A lot of ''old''...''vintage'' doubles set ups used re-purposed cylinders...medical/military...etc...so certification ID on the cylinders will be important...
Your local re-hydro inspection operator will give you all the information you need...
Good Luck...
W.W...
Thank you for your reply, I’ll clean the neck of one of the tanks and see what markings I find. I’ll also check some scrap valve, great advice thanks.
Wouldn't bother.
M25x2 has a max exterior dimension of 25mm. a US 3/4" valve will jam as you thread it into a M25 tank.
The other way is more problematic:
A M25 valve can be screwed into a 3/4 x 14 threaded tank, the fit is a bit sloppy (since M25 is just a bit smaller) and after the first few turns it'll become harder to finally thread the valve all the way in. (difference between 12.7 threads per inch on the metric valve and 14 threads per inch on the tank).
If you are a fool don't despair, it is possible to screw a M25 valve into a 3/4 x 14 tank and the fitting will hold gas untill the valve shoots out as the tank pressure approaches 150Bar (2250 psi). When this happens (and it happens approximately twice a year in Europe), people are killed, maimed or severely injured and the room where the fill station WAS is usually pretty well destroyed.
Michael
Thanks Michael, the valve that I need is bigger than 25mm (26.2 mm) I’ll try to pick up an old 3/4 14 and see how it fits, the valve I need is definitely 14 TPI
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