Re: [PSUBS-MAILIST] Mechanical penetrators

["Dan H." <machine@epix.net>]

Just use the same as a hydraulic cylinder does for a shaft seal.  They use pressures in
the 2000 to 3500 p.s.i. range all the time.  For a shaft seal that only turns valves
you can just use standard buna O-rings.  Make a sleeve that your shaft fits through
with about two or three thousants internal clearance.  Within the sleeve, cut two
internal O-ring grooves.  You really only need one, but to have the double protection
need in a sub, install two O-rings in each penetrate sleeve.  For a fast rotating
shaft, you might want to consider a ceramic and carbon spring loaded face seal.  There
not cheep but they work well.  You'll find them commonly used in fast rotating pumps.

Hope this helps,  Dan H.

Harry Spillett wrote:

> Hello people,
>
> On a similar vein as the electrical penetrator question I am after some
> information on mechanical penetrators. In particular for shafts. Either for
> operating external valves or prop shafts from the thruster motor to the
> prop.
>
> I have made my own sketches but cant see how to make a really good seal to
> withstand diving pressure.
>
> Can anyone point me in the direction of some photos or diagrams,
>
> Thanks
>
> Harry
>
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