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To All,
While looking at various papers on CO2 scrubbers
from manufacturers
etc, I found that none addressed the unique
situation found in submarines.
Most CO2 absorbent is used in anesthetic machines
or rebreathers where
there is a closed circuit. The CO2 breathed out
goes straight into the scrubber
& is removed.
In our subs the CO2 is breathed out & is
diluted by the rest of the air in the
hull & only air with a portion of the CO2 in
the hull goes through the scrubber.
This means that the CO2 level & the pressure in
the hull will progressively climb
unless the volume of air going through the scrubber
is large enough to make an
impact. The Deep Worker 2000 has fans pushing 160
liters per minute, I'm not
sure whether this is per scrubber & whether
they have 2 scrubbers working
simultaneously. But based on 1 fan going, that's
320 x the volume of CO2 being
produced. In the manufacturers guidelines for
scrubbers they recommend that the flow
is at least equal to
the tidal volume of your breath (about 10 liters per minute)
& low enough so that the air has at least 1/2 a second dwell time in the canister.
This could be 32 x less than what Phil has worked out is necessary for the
Deep Worker. I know
the Deep Worker has a small hull & that fluctuations in O2
& CO2 are more critical than a K250, but possibly the same volume of flow is
necessary to achieve
atmospheric control in larger subs.
Also because of the dwell time needed the large
flow required would need large or
long canisters. Deep Worker has 2x 3.35 kg
scrubbers.
On the psub site there is reference to rebreather
cartridges as an option, but from
what I've found you would probably need a number of
these running simultaneously
to make head way.
What are ABS recommendations? & what are others
thoughts / experiences with this.
I'm trying to sort this stuff out for
myself.
Regards Alan
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