din valve question for blue steel tank

[oxyhacker]

The 5-7 thing is a bit confusing. Some sources put it at 200 bar 7 threads and 3000 bar 9, but other put it at 5 and 7. It's easy enough to tell the difference between them when you have one of each to compare but it takes some experience otherwise. Most of the older sources call it 7 and 9, and that's what we say in the book, but lately 5 an 7 seems more common. However I find that if I count the threads on a 300 bar valve or adaptor so as to get the maximum number of threads I will usually get 9, but if I count them as to get the fewest threads I am much more likely to get 8 than 7.

Re 200/300 manifolds, some vendors indentify a manfold by the burst disks installed in it. At one point it was fashionable to use 300 bar manifolds on LP tanks an the theory they must be better, so you could buy 200 bar 300 bar interface manifolds Since the purpose of making them difference in the first place is to prevent people from using a 200 bar regulator on a 300 bar tank, if a 300 bar regulator will screw into a manifold, then I call it a 300 bar manifold, regardless of what burst disks it happens to have in it at the moment.

While I think generally you're right on anything with 5 threads being 232 bar, I've got a Dive Rite RG1225 DIN to Yoke Adapter that is rated for 232(or 233) bar and has 7 threads. So... just because it has 7 threads doesn't mean it's really 300 bar.

 

[Packhorse]

Despite this being a complete answer to your question I suspect this will go on for a few more pages...

Just because the OP's question has been answered does not mean that everything about the subject has been covered and people including the OP may learn more.

FYI in New Zealand if a valve does not have a pressure rating stamped on it then suposably its the "law" that they not be filled above 200bar. Even if it does have 7-9 threads.

 

[oxyhacker]

That's wrong, since the whole point is that a 300 bar reg can be used with a 200 bar valve/manifold, but not vv.

What I meant to say, is that if a 200 bar regulator will not be able to screw into a valve/manifold far enough to work but a 300 bar regulator will, then it's a 300 bar manifold.

if a 300 bar regulator will screw into a manifold, then I call it a 300 bar manifold, regardless of what burst disks it happens to have in it at the moment.