[PSUBS-MAILIST] port ring

Sat Apr 9 18:02:32 EDT 2016

Thanks guys.
I have to make a very embarrassing confession,,,,,
Alan jogged my feeble memory. I did buy an O2 cleaned first stage scuba
regulator for just that purpose about 3 years ago and it is sitting in a
box in my shop. Guess that's what happens when you stop working on your sub
for too long.😎. I am hoping that won't happen again since I just retired!
Rick

On Sat, Apr 9, 2016 at 10:27 AM, Al Secor via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Rick,
>
> Just use an O2 clean scuba regulator...they're good for 100% O2.
>
> Al Secor
>
> --------------------------------------------
> On Sat, 4/9/16, Rick Patton via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>  Subject: Re: [PSUBS-MAILIST] port ring
>  To: "Personal Submersibles General Discussion" <
> personal_submersibles at psubs.org>
>  Date: Saturday, April 9, 2016, 3:10 PM
>
>  Thanks
>  SteveI am trying to keep any high pressure gas outside
>  of the sub including O2 but cant find an O2 regulator yet
>  that can be exposed to salt water unlike the scuba
>  regulaters so I figured I'd have the reg attached to the
>  sked 80 nipple just inside the sub to knock it down to LP
>  and then to the flow meter.Rick
>  On Fri, Apr 8, 2016 at 9:50
>  PM, Stephen Fordyce via Personal_Submersibles <
> personal_submersibles at psubs.org>
>  wrote:
>  Hi Rick,Yep, SCH80 1/2" pipe
>  is good to about 500bar/7500PSI per my favourite pressure
>  rating chart:
> http://prochem.cloudsites.net.au/wp-content/uploads/2013/09/Prochem-Piping-Products-1-Pipe-and-Tube.pdf
>  Hi Hank,I suspect
>  the buckling failure mode and/or standards overriding
>  practicalities (or just inability to achieve close enough to
>  perfect fit) will mean that reinforcement is necessary -
>  really interested to hear what Sean has to say on
>  it.
>  Cheers,Steve
>
>  On Sat, Apr 9, 2016 at 2:56
>  PM, Rick Patton via Personal_Submersibles <
> personal_submersibles at psubs.org>
>  wrote:
>  Does anyone know how much pressure a stainless
>  steel schedule 80,  1/2" ID nipple is rated for
>  3" long? Can it take 3,000
>  psiRick
>  On Fri, Apr 8, 2016 at 4:39
>  PM, Stephen Fordyce via Personal_Submersibles <
> personal_submersibles at psubs.org>
>  wrote:
>  Hi Rick,You're correct there -
>  the reinforcing can be in the form of thickening the small
>  piece of pipe ("nozzle") that is welded on,
>  rather than thickening the shell.  Although it's not
>  very practical for large holes.  There are also limits on
>  how far away the reinforcing can be before it doesn't
>  count.
>  Actually, for
>  small holes, there probably isn't a requirement
>  to reinforce.  I'm not so familiar with ASME, but in
>  the Australian Standard for pressure vessels (which is very
>  similar to ASME), you don't have to reinforce a hole
>  unless it's bigger than 90mm.
>  Cheers,Steve
>  On Sat, Apr 9, 2016 at
>  12:21 PM, Rick Patton via Personal_Submersibles <
> personal_submersibles at psubs.org>
>  wrote:
>  while were on the subject, I need some
>  clarification on the "replace or add what you took out
>  of the pressure vessel skin theory" as when I wanted to
>  add a few extra view ports, I called the captian,Ketterage,
>  and asked about cutting extra holes in the hull and he said
>  the same thing but then got to wondering about that
>  statement.When you cut a hole in the hull and weld in a
>  piece of solid round stainless steel with a 1/2" hole
>  in it for gas/wires, you still have a 1/2" hole in the
>  hull so that theory can only work if you take into
>  consideration the amount of ss rod that is also on the
>  inside and outside of the hull?If that is the
>  case, it doesn't seem correct to use a pipe with a
>  1/2" ID schedule 40 but you extend it inside and
>  outside until you equal the same volume as you
>  removed? Rick
>  On Fri, Apr 8, 2016 at 3:34
>  PM, Stephen Fordyce via Personal_Submersibles <
> personal_submersibles at psubs.org>
>  wrote:
>  Hi Hank and Sean,Given Hank is
>  probably halfway through building this already and Sean
>  might be in the middle of other things I thought I might
>  jump in - I think I can help in general terms.  The rule
>  off thumb is if you make a hole in a pressure vessel,
>  you're supposed to put this material back as reinforcing
>  around the hole to keep the same pressure
>  rating.
>  So if you
>  want to take advantage of the full 4" thickness
>  (wow!!!) and associated depth rating, then you would need
>  to reinforce the hole - and it would need to be a pretty
>  serious reinforcement to replace that thickness of
>  material.
>  Alternatively, if you don't
>  reinforce, then you lose some of your depth rating,
>  because some of the thickness is locally credited as
>  reinforcement.  This means an amount of thickness over
>  the rest of the shell away from the hole is basically
>  dead weight, which may or may not be a problem depending
>  on whether this gets lowered or is
>  free-floating.
>  To put
>  it another way/thought experiment: if you could machine
>  away all the unnecessary material after you've machined
>  the landing area and hole, the result would look like
>  a thinner shell with a reinforcement ring welded around
>  the hole.
>  Cheers,Steve
>  PS: All that said, it seems
>  theoretically possible that if you had a hole with a
>  spherical hatch and the right angles, and it all mated
>  perfectly, that with everything in compression it
>  shouldn't matter there was a hole.  Probably
>  this doesn't account for the buckling failure mode
>  though.  This is getting a bit out of my depth (if
>  you'll pardon the pun!).
>  On Fri, Apr 8, 2016 at
>  11:22 AM, hank pronk via Personal_Submersibles <
> personal_submersibles at psubs.org>
>  wrote:
>  Hi
>  Sean,If a guy was to buy a 48inch id
>  CNG sphere with a 4 inch shell thickness, would it be
>  necessary to weld in a land ring and port seat.  Or could a
>  guy or gal rough cut the necessary holes then put their
>   flange machine to work to machine seats in the shell.
>   It seems logical to me that could be done for the hatch
>  because the load would be supported by the same steel in the
>  hatch.  Or am I out to lunch?  Hank
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