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Re: Unmanned test dives, a safty question
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?
> >
> >