From: Erik Muller <emuller@naic.edu>
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] test of CO2 safety hardware - any volunteers?
Date: Thu, 12 Feb 2004 10:25:28 -0400
OK Pierre, but I suspect that some people will not approve of the inexact
nature of this approach. I am hoping to test its usefulness in a sensible
way:
The idea is that CO2, when mixed with water, forms carbonic acid. The
acidity of water can be estimated using chemical solutions of visual
indicators (or you can get a more exact reading using digital meters), for
example, the chemicals used to measure the acidity (pH) of swimming pools
such as Methyl red.
So it would, I think, be a useful test to simply pump ambient submarine air
through a bit of water containing some methyl red. I have tested the
effectiveness of this in a very preliminary way by blowing into a
water/Methyl red solution with a straw. The solution turns red almost
instantly, within a couple of breaths (thats ok, there is lots of CO2 in my
breath and I am comfortable re-breathing the same air a few times).
What I want to see is how long it takes for the solution to turn red by
pumping through ambient air from a sealed chamber (rather than directly
from my breath). Or if you prefer: how red the solution gets when a person
sits inside a sealed chamber for an hour or so (or whatever length of time
they are comfortable with).
I would suggest that a simple fishtank pump would be very sufficient
($10?). Hopfully any O3 from the electronics wont be significant, though
that too may be important to detect since it is toxic. Methyl red is cheap
and simple to obtain from a swimming pool chemical dealer ($2). If people
dont approve of chemical indicators, they could splurge and fork out for a
more expensive and more exact digital pH indicator. I would be interested
in hearing about results from that too.
In any case, that is all there is to it. I dont think it is TOO foolish and
it might be useful yet. Let me know if pictures would be helpful, though I
dont think there is any one way to pump air through a jar with a bit of
water.
EM.
P.S. While I have peoples' attention, has anyone read the book 'stars
beneath the sea'? I absolutely reccommend it, though it is entirely
focussed on the science, history and evolution of scuba. There is not a
whole lot to do with submarines:
http://www.bluebeyond.com.au/reviews/br-stars.php
Pierre Poulin wrote:
I volunteer!
My sub is air-tight. And I don't think we should go off-list. the more
people involved, the better I think!
Pierre "air-tight" Poulin
From: Erik Muller <emuller@naic.edu>
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] test of CO2 safety hardware - any volunteers?
Date: Thu, 12 Feb 2004 08:38:19 -0400
Hello Folks,
I have a quick request for people with a functioning pressure hull (i.e.
does not need to be a finished sub, just airtight) to see if a simple
idea for measuring ambient CO2 content is useful. Its a VERY cheap
system, and should work as a first-order indicator (i.e. not exact, but
sensitive). Please email me offlist if you are interested and I can
explain my idea. I might even draw some pictures.
EM.
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