Posted by Ken Kurtis on November 14, 2004 at 11:17:45:
In Reply to: Burst pressure is likely 3600 to 4000 for 2400 rated posted by Walt on November 12, 2004 at 09:49:42:
Walt said: "The tank's working pressure is more important . . . "
That's only one factor to consider, and actaully is part of the source for Tim's question.
You've got three things in play here: rated pressure of the tank, rated pressure of the valve threads, rated pressure of the valve burst disc. They all need to be in sync.
For instance, suppose you had a 3000psi tank with a 3442psi valve but only with a 2400psi burst disc. Fill the tank to the stanped, rated pressure and you blow the burst disc.
My understanding on the rating of the valves is that it's based on number of threads (turns) on the valve as well as the depth/strength of the threads. I don't think they'd be a problem using a valve whose rating exceeds the tank pressure, but there might be a problem using a valve whose rating is less than the tank pressure. (And this is wholly seperate from the burst disc issue.)
And if you REALLY want to complicate things, you'd also better factor in the strength/rating of the regulator yoke. Some mfgs limit their regs to 3000psi, yet these same regs are being used on the HP tanks. I don't think they're going to blow, but the point is that the whole issue is not as simple as "Just fill to the tank pressure."
Ken Kurtis
NAUI Instr. #5936
Co-owner, Reef Seekers Dive Co.
Beverly Hills, CA