F02 changes when mixed...?

Okidiver · 13th September 2006, 23:58

Greetings all,

This is probably GasMixing 101, but not been there, so please bear with me...

While picking up my HP 120 c/f tank today

and checking FO2 at 36.4%, the tech mentioned

that she'd recently jammed it and the F02 would probably drop to 36.2% or so when "it all got

mixed up in there." The tank was not warm...

Huh?

While my college chemistry schooling ended after one horrid class

, this isn't making sense. The gas is always mixing, but to the extent of a drop of F02 of .2? Granted, fairly insignificant, but still more than I'd guess.

Could one of you gas mixer gods enlighten me, thx!

***ScubaDadMiami*** · 14th September 2006, 03:31

No matter the theory, whenever I mix Helium with bigger tanks or doubles, it takes a while after for the final mix to settle out especially if a significant Helium addition. If there are pockets of "less mixed" gas in the tank, it can change the final mix reading if you check just after the top off. So, check again in a while.

If it is just oxygen and air, it is pretty much instantaneous.

13th September 2006, 23:58	#1 (permalink)
Okidiver New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jun 2006 Location: Ft Walton Beach, FL, USA Posts: 86	F02 changes when mixed...? Greetings all, This is probably GasMixing 101, but not been there, so please bear with me... While picking up my HP 120 c/f tank today and checking FO2 at 36.4%, the tech mentioned that she'd recently jammed it and the F02 would probably drop to 36.2% or so when "it all got mixed up in there." The tank was not warm... Huh? While my college chemistry schooling ended after one horrid class, this isn't making sense. The gas is always mixing, but to the extent of a drop of F02 of .2? Granted, fairly insignificant, but still more than I'd guess. Could one of you gas mixer gods enlighten me, thx! __________________ Rapid Rick
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14th September 2006, 03:31	#2 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 2,044	Re: F02 changes when mixed...? No matter the theory, whenever I mix Helium with bigger tanks or doubles, it takes a while after for the final mix to settle out especially if a significant Helium addition. If there are pockets of "less mixed" gas in the tank, it can change the final mix reading if you check just after the top off. So, check again in a while. If it is just oxygen and air, it is pretty much instantaneous. __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
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