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Re: To Gary

Thanks

Alan

protek@shreve.net wrote:

>     No, I was using the chart on page 815.  "Naval Civil Engineering
> Laboratory" chart for flat plane windows.  Actually it is the lower end and
> not well defined with the curve.  It looked to me like the short-term
> critical pressure was around 5-Mega Pascals.  I used a factor to get
> pressure in PSI.  Stachiw recommends a factor of, I believe 7 or 8.  This
> will take into consideration certain scratches, cycling, temperatures and
> other normal abusive conditions.
>
> Gary B
>
> At 10:24 PM 3/1/99 -0800, you wrote:
> >Hi Gary,
> >
> >I take it that you are using the chart on page 284 ?
> >I believe the use of a safety factor of 5 is from A.B.S.
> >Thanks for pointing this out.
> >
> >protek@shreve.net wrote:
> >
> >>     I just looked up the short term critical loading failure prediction for
> >> the window you mentioned and it is right at 725 PSI from the chart in
> >> Stachiw's book.  It recommended you use a factor of 8.  I built my
> >> annealing oven with a closed loop of aluminum with a high temp blower
> >> purchased from Grainger.  I packed the whole assembly in a plywood (UhOh!)
> >> box with a lot of fiberglass insulation backed around it.  I have a
> >> resistive heater in the channel with a location where I can place the
> >> window inside the channel.  The circulating air keeps the temp constant.
> >> Stachiw's book has the numbers for annealing.  You need two cycles.  I used
> >> a computer to monitor the temps and control the heating.  It took a full 10
> >> hours to run one window.
> >>
> >> Gary B.
> >>
> >> At 09:05 PM 3/1/99 -0800, you wrote:
> >> >Hello again Jon,
> >> >
> >> >Well maybe it wasn't as load as it seemed, you see, this was my first
> >> destruction
> >> >test and I was exited and not sure what to expect,
> >> >it took me by surprise!  It sure did seem load... anyway...
> >> >
> >> >The "bang" was just the port.
> >> >The test chamber is about 3 ft in length and 18 in. dia.. It belongs to my
> >> friend
> >> >Doug Previtt of Delta Oceanographics.
> >> >I feel very lucky to have access to his facilities, He is a very nice guy.
> >>  He
> >> >has been building subs (about 7 or 8) for over 35 years.
> >> >His sub, the Delta has over 4000 dives all over the world with a perfect
> >> safety
> >> >record.  He has dove for many government agencies and institutions, and
> >> on, and
> >> >on, and on...  I think you get the idea.
> >> >
> >> >When I was a kid my hero was Clint Eastwood.
> >> >As an adult... sorry clint, doug has you beat !
> >> >He has done in his life what I am just beginning.
> >> >
> >> >Sorry, back to the subject.
> >> >
> >> >The view port I was testing was a flat, acrylic disc, 1 in. thick, flat
> >> bearing
> >> >surface flange, I.D. of 6 in, O.D. of 8. this of coarse gives me a DO/DI
> >> ratio of
> >> >1.333 which is above the minimum 1.25 acceptable. I needed the port to
> >> maintain
> >> >to 675 psi to get my safety factor of 5 and it blew at 760 psi which
> puts the
> >> >depth at 1707 ft.  My operating depth goal is 300 ft. so I'm in the
> green !.
> >> >Oh yeah, the port I tested was not even annealed, even better because the
> >> ports I
> >> >use will be.
> >> >
> >> >Do you know anything about how to make a good port annealing oven ?
> >> >ttyl
> >> >Alan Long
> >> >Subview
> >> >Jonathan Shawl wrote:
> >> >
> >> >> Alan Long wrote:
> >> >>
> >> >> > Jon,
> >> >> >
> >> >> > Of coarse the chamber was water filled !
> >> >> > What did I say that made you feel I was using air ???
> >> >> > >It sounded like a gun shot !!!
> >> >>
> >> >> I didn't think it would be that loud if it was a small water filled test
> >> rig.
> >> >> I guess I made an assumption, sorry about that.
> >> >> Was the bang just from the cracking or exploding plastic view port?
> >> >> How big was the water filled chamber? volume?
> >> >> How big was the lens?
> >> >
> >> >
> >
> >