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Re: [PSUBS-MAILIST] dual hull??
I considered something similar to that for the mold for my concrete sphere.
(For under-sea habitation, obviously!) But ran into other snags, besides
the fact that I do NOT have the money to make THAT happen!
Warren.
>
> Hi,
>
> I think Ray gave a good answer to the multi layer pressure hull.
> But, uou could always make the spacing bigger and fill it with
> concrete...
>
> Something similar that could work: coil high pressure
> piping all the way along the inside of the hull cylinder, with
> the pipe coils kind of acting like framing for the cylinder but
> bunched up very close (touching even). Now if you pressuring
> the high pressure piping it will provide support for the hull.
> You could even exposed the inside of the piping to external
> pressure. The idea being that the pressurized piping keeps
> the hull under internal tension (kind of like the hull had been
> pressurized). Carl T.F. Ross's book "Pressure Vessels: External
> Pressure Technology" as a couple of paragraphs discussing this
> idea/method.
>
> Ian.
>
> On Wed, 29 Jan 2003 17:59:11 -0700
> jbarlow@bjservices.ca wrote:
>
> > I sent to the wrong address before, but I'm still curious.
> >
> >
> > ----- Forwarded by James Barlow/BJSCAN/BJSERVICES on 29/01/2003 05:54 PM
> > -----
> >
> > James Barlow
> > To: owner-personal_submersibles@psubs.org
> > 29/01/2003 10:31 cc:
> > AM Subject: Dual Hull Concept
> >
> >
> >
> >
> >
> > I'm just thinking out loud here..
> >
> > If you have a 36" [914.40 mm]OD x 0.500" [12.70 mm] WT outer hull and put
> > inside a 34" [863.60 mm] OD x 0.500" [12.70 mm] WT inner hull. ( leaving an
> > annulus of 0.500" per side) and fill that area with hydraulic oil that you
> > pump up to some high pressure. The pressure is equal everywhere but the
> > area on the outer hull is greater, resulting in a net force outward.
> >
> > 36 - 0.5 -0.5 = 35.000" ID [889.00 mm]
> >
> > 34 OD of inner hull = [863.60 mm]
> >
> > If the was 100 psi oil pressure in the annulus area then the force out
> > would be:
> > 100 psi x 355/113 (pi) x 35.000" x length = 3500 pi x L pounds
> > [7.030696 kg/cm2 x 355/113 x 88.900 cm = 625.029 pi X L ]
> >
> > force on inside would be:
> > 100 psi x 355/113 (pi) x 34.000" x L = 3400 pi x L pounds
> > [7.030696 kg/cm2 x 355/113 x 86.360 cm = 607.171 pi X L]
> >
> > a direct ratio of diameters. (id outer / OD inner)
> >
> >
> > If you are 100 psi deep (6.80 atm (217 feet [66 m])
> > then the outer hull would see 2.8 psi differential. (ratio of 36" / 35")
> > (OD/ID of outer hull)
> >
> >
> >
> > Negating yield of outer hull due to increasing inner (which you can't do
> > but maybe you would want to fill with a compressible gas like nitrogen
> > instead of oil) the inner hull sees the same 100 psi, but the outer sees
> > outside pressure less roughly 100 psi.
> >
> > Did I miss something??
> >
> >
> > Of course you essentially have a 33" [838.20 mm] ID Hull now... and one
> > that weighs essentially the same as a 33" ID [838.20 mm] x 1" WT [12.70 mm]
> > hull.
> >
> >
> > The pressure rating of such a hull would be great anyway. However perhaps
> > as the inner hull only sees 100 psi and is protected from mechanical
> > damage, it could be made from fibreglass or some such material to save
> > weight.
> >
> >
> >
> > All the numbers above are only just numbers I threw in for illustration.
> > It wouldn't have to be a 1/2" wall thickness hull.
> >
> >
> >
> > Not to start any wars, I'm not advocating the use of dual hulls. Just
> > curious...
> > Comments?
> >
> > Jay.
> >
> >
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--
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