Re: [PSUBS-MAILIST] No Machining Hatch Sealing Concept

[Jon Wallace <jonw@psubs.org>]

Jay and Alec both make good points.  I also wonder if the 1/4 inch beads 
become the weak point of the sub.  Given your rendering, I can see why 
Peter used square stock.  What becomes evident to me is that you've only 
got 1/4 inch material at the cross section of the hatch ring.  With 
square stock you would have a consistent thickness which would be better 
resisting overall pressure.  Regarding Peter, you have to also keep in 
mind that he did not dive his subs at relatively great depth.

Jon

Smyth, Alec wrote:
> The reason an O ring seals so well is that, so long as there is an 
> initial seal, increasing pressure expands the width of the O ring thus 
> increasing it's sealing ability. In other words, the higher the 
> pressure the better it seals. In this case the two SS rings that sit 
> on the Sikaflex won't expand. The Sikaflex seat will deform under 
> pressure, but in the opposite way you want it to. Pressure will tend 
> to expand the Sikaflex to deepen the recess under the SS rings and 
> tunnel under them. I'm not saying it wouldn't work at all. I think it 
> would, but only at low pressures.
>  
> At least that's my take. Very nice renderings though!
>  
>  
> Alec



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