In a message dated 8/28/01 1:44:42 AM Eastern Daylight Time,
SLaifman@SoCal.RR.com writes:
> t is not correct, and not in accordance with SAE or aircraft/aerospace
> design criteria. A proper o-ring seal is between two flat surfaces. One
> is genuinely flat, and the other is a very specific square cross
> section. Not round. The o-ring is squeezed by the opposing flat surfaces
> of the top and the bottom of the grooved portion. This causes the o-ring
> to expand against the right angled side-wall and the seal is made there.
> Increases in internal pressure cause the o-ring to press even harder
> against these surfaces, making the seal even better at higher pressures.
>
>
Steve, great explanation . You should post that on your web site.
> The only failure you have ever heard about was from a design that was
> operated at an ambient temperature too cold for the o-ring to have the
> proper resilience to seal the moving gap quickly enough. Their solution
> was a joint re-design, to increase o-ring compression with vessel
> expansion, and multiple o-ring seals. Ours already sealed harder with
> expansion/rotation and only used 1 o-ring. This is not a criticism of
> the original design, as the system that failed was used outside the
> temperature design limitations, and the users knew it. It was redesigned
> using a "belts, suspenders, and super glue" approach due to the human
> risk factor.
And this case took out more than a Ford small block.
Rob on the Space Coast Kempinski
|