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Re: [PSUBS-MAILIST] Sgt. Peppers O2 consumption rate question.
----- Original Message -----
From: "Carsten Standfuß" <MerlinSub@t-online.de>
"Hi Pat .. I do not like cubic feet.. "
Hi Carsten!
I don't blame you! I didn't think the conversion would be this complicated,
but I appreciate your efforts.
Over here, when they say a pressure bottle holds 20 cubic feet of Oxygen,
they mean it contains the amount of pure O2 that would fill an area of 20
cubic feet at one atmosphere pressure, which has then been compressed to fit
inside the tank. My "20 cubic foot tank" is about 13 inches tall (32.5 CM)
and about 5-1/4 inches in diameter (13.125 CM). I just bought it; and
assuming it was properly filled (and there is the chance it might not be
completely full, and/or that my old pressure gauge is a little inaccurate),
the O2 inside seems to be compressed to about 1800 PSI (about 122
atmospheres).
Now, let me make sure I understand the rest of your equations:
"the equal of 20 cubic feet = 0,566 cubi meter or 566 liter (Hope thats
right..)"
OK. So 20 cubic feet equals about 566 liters, correct?
" With a "You need at least 0,25 Liter/minute O2 each person. 566/ 0,25 =
2264 Minutes divided by 60 Minutes = 37,73 hours. One day, one night,
another day and the game is over."
So, figured on an average Oxygen consumption rate of about 0.25 liters of O2
per person / per minute: one liter of O2 would last one person about 4
minutes; and 566 liters would last 2264 minutes, or 37.73 hours; right?
Not meaning to doubt you, (you are admittedly better at converting Metric
than I am) but are you SURE we didn't drop a decimal point some place? I
would be extremely happy to get 37 hours out of my little O2 bottle; but
that seems almost too good to be true. Are we sure it's not more like 3.73
hours?
" Sgt.Peppers use a pure O2 closed cycle rebreather"
In the NAUTILUS, I'm removing the CO2 from the atmosphere with a SODASORB
scrubber; recycling the same old nitrogen; and adding O2 as it is depleted.
"Normaly the free air inside my sub works for a maximium of 40 minutes
(starting strong headeges)"
That's about what I was getting in the NAUTILUS without any life support
system; after about 45 minutes, it started getting hard to breathe. I
figure the volume of the pressure hull was about 35 cubic feet (about 991
liters?), and she displaces about 2225 lbs. about 1011.36 kilos).
So, given these specifications about my submarine hull and life support
system, do you still think my new 20 cubic foot O2 bottle will last me about
37 hours?
" Hope helps a little - keep me inform if you get the scrubber consumtion
figure for different materials out. "
It helps a lot; thanks for all your efforts. Muchly appreciated.
" Hope to send new pictures at the end of this week." Carsten"
Looking forward to seeing them.
Thanks again!
Pat