At 09:27 AM 06/03/97 +0100, you wrote:
>
>EdHoo wrote:
>
><snip>
>
>>A negative aspect is that Odin 1st and the 2nd stages are _BOTH_
>>upstream valves.  It means if anything goes overpressure they slam
>>shut.  In contrast downstream regulators would free flow and you could
>>still breathe (I new about the 2nd stage and that is probably why George
>>trashes it all the time, the 1st stage is news to me).
>
><snip>
>
>
>I wonder that it is true. I can't see the advantage of using upstream
>valve...
>I know Poseidon regs have an overpressure valve on the 2nd stage, but I
>can't believe they stop giving you air in case of overpressure...
>
>Can someone explain me more about this??
>
>Regards, Stefano

The Odin first stage IS NOT an upstream valve, it is a balanced diaphragm
unit very similar to the USD, Dacor and several other designs.  In event of
a first stage malfunction, it has a tendency to deliver too much air to the
second stage not shut down.
The second stage like most servo assisted units is an upstream valve, hence
the safety release built into the hose. As stated in the manual, the max IP
for the Odin is 152 PSI
and the safety release is set at 247 psi. Because of the leverage on the
servo valve, their is little or no noticable difference in the cracking
effort even with an IP set near the release pressure. If the second stage
were somehow used with a hose without the safety release, I would be more
worried of a hose letting go than the second stage locking in event of a
first stage malfunction. But then again, anyone bright enough to jerry rig
the wrong hose, probably wouldn't even be fizzed by the ringing in his ears:-)


Ian
marshall@va*.co*
<http://www.vaxxine.com/advtech>
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