Do you mean the 'O' ring in the face of the din fitting. Or are you referring to a seal inside the reg itself.
200 vs 300 bar manifold
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Do you mean the 'O' ring in the face of the din fitting. Or are you referring to a seal inside the reg itself.
Look...manufacturiong tolerances being what they are and considering you have a valve made my company A and a DIN connection made by company B, you'll be lucky if 3 of the 5 threads are actually in contact, so 5 versus 7 is a moot issue as 3 is already enough. Worst case if it is over pressurized, whatever thread is the "high" one taking the load will set back slightly until another thread picks up the additional strain.
The same basic things happens with rifle lugs when a round is fired that is vastly overpressure (for example a proof round). If anything, you just get some set back and increase the bearing surface of the lugs. It is a similar case where the device is over designed to the point something else will fail first. in the case of a rifle the cartridge case will fail first, not the action of the gun. In a DIN valve, an o-ring will fail before the threads.
Consistent with that concept, if it did "fail", the failure of the DIN connection would not be catastophic. Instead the connection would stretch slightly creating excessive end play and the o-ring on the end of the DIN connection would then extrude, venting gas out the small hole in the side of the valve (which is what it is for). So worst case you get a leak, not a reg in the back of the head.
A yoke valve fails in a similar manner. The brass yoke just stretchs slighty when its rated pressure is exceeded (by about 1.5 times the pressure stamped on the yoke). The o-ring in the face of the valve is then no longer fully contained and will extrude, allowing gas to escape. So again, what you get is a leak not a reg in the back of the head.
The extra lenght of the 7 thread 300 bar valve has two more threads to hold water - increasing the potential to blow water into the tank during a fill. It is also longer and less supported so it has more potential to get bent if the tank falls over. 200 bar valves are more than strong enough, are less likely to get damaged and are easier to dry prior to a fill.
In short, unless you are truly talking about 300 bar pressures (4350 psi) a 200 bar valve makes a lot more sense and in the vast majority of cases, we are talking about 3500-3800 psi pressures that are not significantly higher than the 3442 psi "approved" for 200 bar vavles.
3800 psi is only a 10% increase over 3442 psi - well within the mechanical design limits of a 200 bar DIN connection. To make the point more obvious, 3800 psi is only 15% over the 3300 psi commonly accpted in yoke valves and many modern heavy yokes with 9/16" yoke screws will tolerate 4000 psi before stretch becomes an issue.
The same basic things happens with rifle lugs when a round is fired that is vastly overpressure (for example a proof round). If anything, you just get some set back and increase the bearing surface of the lugs. It is a similar case where the device is over designed to the point something else will fail first. in the case of a rifle the cartridge case will fail first, not the action of the gun. In a DIN valve, an o-ring will fail before the threads.
Consistent with that concept, if it did "fail", the failure of the DIN connection would not be catastophic. Instead the connection would stretch slightly creating excessive end play and the o-ring on the end of the DIN connection would then extrude, venting gas out the small hole in the side of the valve (which is what it is for). So worst case you get a leak, not a reg in the back of the head.
A yoke valve fails in a similar manner. The brass yoke just stretchs slighty when its rated pressure is exceeded (by about 1.5 times the pressure stamped on the yoke). The o-ring in the face of the valve is then no longer fully contained and will extrude, allowing gas to escape. So again, what you get is a leak not a reg in the back of the head.
The extra lenght of the 7 thread 300 bar valve has two more threads to hold water - increasing the potential to blow water into the tank during a fill. It is also longer and less supported so it has more potential to get bent if the tank falls over. 200 bar valves are more than strong enough, are less likely to get damaged and are easier to dry prior to a fill.
In short, unless you are truly talking about 300 bar pressures (4350 psi) a 200 bar valve makes a lot more sense and in the vast majority of cases, we are talking about 3500-3800 psi pressures that are not significantly higher than the 3442 psi "approved" for 200 bar vavles.
3800 psi is only a 10% increase over 3442 psi - well within the mechanical design limits of a 200 bar DIN connection. To make the point more obvious, 3800 psi is only 15% over the 3300 psi commonly accpted in yoke valves and many modern heavy yokes with 9/16" yoke screws will tolerate 4000 psi before stretch becomes an issue.
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Thank you DA; you always seem to find the time, and words to properly address the issue at hand without ruffling too many feathers….you have a gift.
I keep 200 BAR valves on my tanks and 300 BAR DIN regs. That way I know if I am travelling that my regs will fit any tank DIN valve....and if I need to rent a reg (on a trip) I can put a plug in the valve and a yoke reg will do at a push.
Cheers,
Norman H.
Cheers,
Norman H.
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