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Marc T · 23rd December 2007, 13:35

Quote: (Originally Posted by Mdemon)

Yes, I was trying to find out roughly how much lower - my Maths isn't that good.

The scrubber is mounted horizontally. You raise a good point about water - I'll have to add some absorbent just in case. I could switch the gas flow too, I am still thinking what this could do to the scrubber efficiency though.

So very rough thought

What you certainly dont have to enter in the computations is ambient pressure due to the definition of partial pressure.

Few computations ( considering one vol of O2 become a vol of co2, show that at ambient pressure, the difference of ppo2 is the same whatever the inhale ppo2 is ).

The difference of ppo2 between inhale and exhale is always the same, whatever the exercice and consumption of O2 are, only the flow is increased.

So I guess the difference of ppo2 between inhale and exhale is always the same whatever the conditions are.

So what you have to do is to calibrate and then exhale only one time in the scrubber so the difference between 0.21 and the displayed value will be the difference youll always have between inhaled and exhaled gaz.

BUT AFTER the scrubber its an other storry because CO2 have been scrubbed, then the PPO2 increase BEFORE any O2 addiction.

So if your sensor is before scrubber, you can think that the solenoîd will give you a more O2 than if it was after and the difference will increase with the quantity of scrubbed O2...so perhaps not a good idea.

Hum dont know if what I wrote worth 2 pences

Cheers

Marc

23rd December 2007, 13:35	#6 (permalink)
Marc T hell is in the details Current Rebreather/s: RB80 / Clone Home Build Other Rebreather/s: Not Bought Yet RB80 / Clone Home Build Join Date: Sep 2005 Location: FRANCE Carcassonne Posts: 495	Re: O2 cells before or after the scrubber? Quote: (Originally Posted by Mdemon) Yes, I was trying to find out roughly how much lower - my Maths isn't that good. The scrubber is mounted horizontally. You raise a good point about water - I'll have to add some absorbent just in case. I could switch the gas flow too, I am still thinking what this could do to the scrubber efficiency though. So very rough thought What you certainly dont have to enter in the computations is ambient pressure due to the definition of partial pressure. Few computations ( considering one vol of O2 become a vol of co2, show that at ambient pressure, the difference of ppo2 is the same whatever the inhale ppo2 is ). The difference of ppo2 between inhale and exhale is always the same, whatever the exercice and consumption of O2 are, only the flow is increased. So I guess the difference of ppo2 between inhale and exhale is always the same whatever the conditions are. So what you have to do is to calibrate and then exhale only one time in the scrubber so the difference between 0.21 and the displayed value will be the difference youll always have between inhaled and exhaled gaz. BUT AFTER the scrubber its an other storry because CO2 have been scrubbed, then the PPO2 increase BEFORE any O2 addiction. So if your sensor is before scrubber, you can think that the solenoîd will give you a more O2 than if it was after and the difference will increase with the quantity of scrubbed O2...so perhaps not a good idea. Hum dont know if what I wrote worth 2 pences Cheers Marc Last edited by Marc T : 23rd December 2007 at 13:39.
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