Re: [PSUBS-MAILIST] Double O-Ring On A Hatch

[clientes@tolimared.com]

Hello Oystein,

Very good link - thanks,

I see your point what concerns difference to normal hatches - in fact  
i am considering the model of the scuba gear seal as a model for a  
deep diver - hatch i have in mind - could go to ocean bottom - based  
on concrete spheres...

In any case the point seems to be that the mecanism that makes a  
o-ring fail is extrusion trough a gap. As long as you avoid this  
properly a o-ring will hold hundereds of bar = thousands of meter of  
waterdepth...

If you have several rings and a big gap due to deficient machining -  
ALL of them will fail at the same depth.

In hydraulics that normally work at that kind of pressure you have all  
kind of single o-rings...


Cheers, Wil


Quoting Øystein Skarholm <skarholm@gmail.com>:

> In scubagear the seat for connenction between tank and the 1st stage is
> spesial in that manner that the oring is in a deep groove and the 1st stage
> seat goes into this groove, unlike one on a hatch. Having said that there
> are plenty off hi pressure applications seald off using single o-ring.
>
> http://o-ring.info/en/technical%20manual/ERIKS%20-%20Technical%20Manual%20-%20O-Ring%20Sealing%20Principles.pdf
>
>
>
>
> On 8/8/07, clientes@tolimared.com <clientes@tolimared.com> wrote:
> > In a scuba gear the first stage - is attached to the tank with a
> > single O- ring this single o-ring takes some 200bar in this
> > configuration - or i am wrong on this? - So i also see no need of
> > double ring in any application in a submarine.
> > Cheers, Wil
> >
> > Quoting MerlinSub@t-online.de:
> >
> > > No idear why they make that.. one is just fine with lower
> > > cost for rings, trench and paint maintance issue.
> > >
> > > I just pressuries my diverchamber with a
> > > singel o-ring to 32 atmosp..
> > >
> > > Think better one with bigger diameter than two smalls.
> > >
> > > best regards Carsten
> > >
> > > "Brent Hartwig" <brenthartwig@hotmail.com> schrieb:
> > >>
> > >>
> > >> I finally found a double o-ring on a sub hatch. The sub on ebay
> > >> right now called the Great Lake's Submarine mentioned earlier, has
> > >> one. Here is the picture.
> > >>
> > >> http://www.frappr.com/?a=viewphoto&id=4001713&pid=7375620
> > >>
> > >>
> > >> Regards,
> > >> Brent Hartwig
> > >
> > >
> > >
> > >
> > >
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> --
> Best Regards
> Øystein Skarholm
> www.ubat.no







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