Re: more cabin questions

["Alan D. Secor" <secor@btv.ibm.com>]

> 
> Ok, the scrubber sounds pretty straight forward...but he's another
> silly question.  If oxygen is allowed to bleed into the cabin, eventually
> the pressure should rise past 1ATM.  What method is used to counter the
> buildup of atmospheric pressure in the cabin?  Is some sort of pressure
> relief valve used?
> 
> Jon
> 
Not silly at all....you bleed O2 in at the rate you metabolize it.  For
instance, a body at rest may metabolize something like .2-.5 liters per
minute of O2.  Therefore you just flow the O2 at that rate.  I plan on
having an onboard O2 analyzer (which I can show you how to build from a
sensor and voltmeter) to monitor if the concentration is too high or too
low. Also, I plan to have a barometer onboard to monitor changes in cabin
pressure.  You'll also need a vent valve for when you surface, if the 
cabin
pressure is slightly negative with respect to outside, you'll never get
you hatch open ;-)  Ray has asked me to send him a photo of all my parts
I have collected to date so you'll be able to see the various regs, flow
meters, scrubber parts, etc on the web page (hopefully in the not too
distant future)!
--
Al Secor
e-mail: secor@btv.ibm.com