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RE: [PSUBS-MAILIST] Welder with Vision
Rob,
Yes, that method (steel over concrete) has been used
very successfully in a number of negative pressure
industrial applications that I have worked around. The
most impressive that I have seen was an access tunnel
THROUGH an open steam boiler. It was never intended
for human use, but rather to allow a conveyor to move
coal through to ease delivery to the firebox, and also
to preheat the coal. The pressure (working) was about
450psi, and at a temp of over 600 degrees f. It did
not however have any end caps as it passed all the way
through the boiler. The whole assembly, as I
understand it, was constructed in the 1930's, if I
recall correctly.
Dewey
--- robertbatta@comcast.net wrote:
>
> Dewey,
>
> Thats a really interesting concept, is this method
> used somewhere ? NASA ? It would be a lot easier
> to build, less metal work.
>
> The "grain silo" is what I was going for - my
> mistake for saying cone - I do not plan on using a
> cone, my earlier description was focused on the
> conning tower, I should have been more detailed.
>
> Thanks,
>
> Rob
> > Rob,
> > Have you considered a composite? Either FRP over
> or
> > under steel, or a metal outer, monolithic concrete
> > inner hull structure? Even a multi-faceted
> hemisphere
> > would be stronger than a cone, I would think. With
> as
> > many as 20-30 plates. Like the tops of grain silos
> are
> > done. I have a friend in materials design at NASA,
> and
> > he and I have discussed the possible merits of a
> metal
> > outer, from lighter gage steel or aluminum, with
> an
> > injected plastic liner, say 1-2" thick. The
> > possibilities are many, and different hull
> materials
> > might be easier to work with and considerably
> stronger
> > than steel.
> > Dewey
> > --- robertbatta@comcast.net wrote:
> > > Alec,
> > >
> > > Exactly what I was looking for - thank you for
> your
> > > insight.
> > >
> > > Rob
> > >
> > > > Rob,
> > > >
> > > > When you think of basic shapes applied to
> pressure
> > > vessels, what you
> > > > might call a "desirability rating" in
> > > best-to-worst sequence is as
> > > > follows:
> > > >
> > > > 1) Sphere
> > > > 2) Cylinder
> > > > 3) Cone
> > > > 4) Flat surface
> > > >
> > > > That is, a sphere is more efficient than a
> > > cylinder, etc. Things like
> > > > elliptical cylinders or elliptical endcaps
> would
> > > fall somewhere in
> > > > between. Of course you see all sorts of flat
> > > surfaces or odd shapes on
> > > > submarines from the outside, but I'm talking
> of
> > > the pressure hull
> > > > proper, on 1 ATM boats.
> > > >
> > > > So I have two suggestions:
> > > >
> > > > For the endcaps, the ideal would be
> hemispheres
> > > instead of "flatter"
> > > > cones. However if you find hemispheres of the
> > > desired measurements to be
> > > > non-standard and thus expensive (this happened
> to
> > > me), then try for
> > > > elliptical endcaps, which are still a better
> > > approximation to a
> > > > hemisphere than a cone is.
> > > >
> > > > Second, you might consider two vertical
> cylinders
> > > for the coning tower
> > > > instead of a half pipe. The reason spheres and
> > > cylinders are efficient
> > > > at resisting pressure is because the forces
> > > created on the surfaces are
> > > > evenly distributed. There must be a more
> elegant
> > > way to put it, but if
> > > > you think of a sphere, the force on any point
> has
> > > an identical opposing
> > > > force on the opposite side. This is true of a
> > > cylinder too, but it is
> > > > NOT true of a half pipe. Plus, with the half
> pipe
> > > you have the challenge
> > > > of closing the ends, and especially of
> providing a
> > > hatch seat, in what
> > > > would be a curved surface. That is if you're
> > > planning a hatch on top of
> > > > the coning tower.
> > > >
> > > > Hope that helps, and I apologize in advance if
> > > I've stated things that
> > > > might be too obvious.
> > > >
> > > > Thanks,
> > > >
> > > > Alec
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: robertbatta@comcast.net
> > > [mailto:robertbatta@comcast.net]
> > > > Sent: Tuesday, December 30, 2003 4:45 PM
> > > > To: personal_submersibles@psubs.org
> > > > Subject: Re: [PSUBS-MAILIST] Welder with
> Vision
> > > >
> > > > Thijs,
> > > >
> > > > That is the design I had in mind. My last sub
> was
> > > a single occupant in
> > > > the prone position, I am looking to "upgrade".
> > > >
> > > > I realize the design is complex, Im hoping to
> get
> > > feed back from you all
> > > > on this. To answer your question, yes, this
> is
> > > the design I had in
> > > > mind, two occupants, one in front of the
> other.
> > > >
> > > > Thanks,
> > > >
> > > > Rob
> > > >
> > > > > Rob,
> > > > >
> > > > > What you discribe makes me think of a Perry
> > > Cubmarine (If you don't
> > > > know
> > > > > what that looks like have a Google image
> search
> > > for "PERRY
> > > > CUBMARINE".) A
> > > > > design like that gives you the opportunity
> to
> > > have 2 people sitting
> > > > upright
> > > > > in a small sub. I fear that it is
> complicated to
> > > design (stresses!)
> > > > and
> > > > > build. Is this the concept you have in mind?
> > > > >
> > > > > Geatings,
> > > > > Thijs Struijs
> > > > > The Netherlands
> > > > > ----- Original Message -----
> > > > > From: <robertbatta@comcast.net>
> > > > > To: <personal_submersibles@psubs.org>
> > > > > Cc: "Carsten Standfuss"
> <MerlinSub@t-online.de>;
> > > > > <personal_submersibles@psubs.org>
> > > > > Sent: Tuesday, December 30, 2003 8:59 PM
> > > > > Subject: Re: [PSUBS-MAILIST] Welder with
> Vision
> > > > >
> > > > >
> > > > > > Not as of yet, I will send them when
> complete,
> > > I may even hand draw
> > > > > something to get my questions answered. I
> am in
> > > the process of moving
> > > > from
> > > > > one home to another, once settled in, I plan
> on
> > > building a cardboard
> > > > mock up
> > > > > to nail down the measurements. The pressure
> > > hull is nothing more than
> > > > a
> > > > > pipe with end caps (30 or 45 Degree Cones),
> the
> > > pilot and passenger
> > > > are in
> > > > > the sitting position, their upper bodies and
>
=== message truncated ===
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