Re: [PSUBS-MAILIST] DEEP WORKER

[CWall@swri.edu]

Another question for you 1 atm guys:

When your design includes pressure flasks carried internally, do you do
engineering failure analysis to determine the effect of an unplanned release of
 the contents into the pressure hull?

Obviously, the volume in a scuba tank suddenly emptied into a hull is not going
 to overpressurize it- but I wonder about busted fittings on oxygen tanks,
etc., causing some other problem due to a release into the hull- say a hatch
leaking before you got to the surface because of raised pressure, or (God
Forbid!) a CO2 cartridge getting popped on an inflatable Mae West that you had
to vent because it pinned you in the conning tower, etc...

Put another way, for those of you carrying significant high pressure air
internally, do you typically look at worst case scenarios for internal leakage?
 (I know it's unlikely, but I'm just doing some range finding for the depth of
concern...)

Craig Wall
---------- Original Text ----------

From: "nick" <timely@jps.net>, on 11/30/00 11:52 AM:
To:
Incognito2@CTC@SwRI26[<personal_submersibles@psubs.org>],Incognito2@CTC@SwRI26[
"Jeff Russell" <je_russell@yahoo.com>]



Phil Nuytten wrote:

> Hi, Pat:
>         We carry 100 cubic feet of O2 ( 2 standard SCUBA '50's) and two Co2
> scrubbers with a rated duration of  36 hours each ( 72 hour total) and an
> actual of about 43-45 hours each ( 86-90 hours total). Deepworker has an
> life support system that is briefly described  in a DW2000 technical paper
> on  Nuytco's website -( www.nuytco.com ) The reason for two O2 tanks and
> two scrubbers is that we also have two bellows-add controllers, two
> continous-flow metered orifices, two sets of analog supply pressure and
> intermediate pressure guages, and two sets of emergency by-pass valves . .
> .in other words, two complete, independant, redundant, life support
> systems.  If the port side fails, we still have 36 hours on the starboard
> side, plus the ability to do a passive breathe (via  oral/nasal mask)
> through the second scrubber to restore full 72 hours - hence the reason for
> the large 02 supply on both sides, going in. You could wipe out one side
> completely and still have one functioning side plus a fully accessible
> second scrubber. At a conservative minimum exertion consumption rate of .25
> to .35 lpm 02, a single 50 of 02 would last around a 100 hours - or  about
> the actual scrubber time.
> Phil Nuytten
>