02 Feed on exhale lung

You'd have to be hammering the hell out of your MAV, have bad sensors, and/or not paying attention to your PPO to get a tox hit. I'd say darwin has come to visit at that point...

Even from 80-130ft, its still around 20-30m to tox, depending on how high a PPO of course. Depth may make it shorter, but I'd still say you'll have done it long enough to make it a pretty monumental f'up.
 
Jeff Pack said:
You'd have to be hammering the hell out of your MAV, have bad sensors, and/or not paying attention to your PPO to get a tox hit. I'd say darwin has come to visit at that point...

Even from 80-130ft, its still around 20-30m to tox, depending on how high a PPO of course. Depth may make it shorter, but I'd still say you'll have done it long enough to make it a pretty monumental f'up.
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Your instructor died from the results of what most are assuming was an O2 tox while diving with you. I would think that you are particularly well placed to appreciate any alternate device or procedure that could prevent that.

Peter
 
rjack said:
My experience with partial pressure "layering" is similar to others, it does appear to happen and if you fill very slowly its actually worse. I partial pressured some 250cf storage bottles with my 3cfm compressor once. After filling they analyzed at 24%, 3 days later (they were vertical) they were 32%. I suspect its mostly due to differences in temperature, not inherent density differences between O2 and air.

Richard is this really the results your getting due to Temps?
What is the mix after day 2 ..never have I seen a big difference like that, got me thinking when you guys go to your LDS what really do you walkout with!!!
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Yeah but remember its a 3 cf per min compressor into 3x 250cf storage bottles. The air was going in hot but sloooooowwww. It took like 3 hours to fill them. They are plumbed together into one big bank.

I bought the bottles for my storage bank, they had leftover O2 in them from the defunct dive shop I bought them from. So I used the O2 down to the point where I could partial pressure them back up to be full of EAN32. It was a one shot exercise about 7 years ago. But I did analyze them after I got them full and a few days later. And they really were layered quite dramatically. Obviously I couldn't lay them down. My experience has been that the larger surface area of a horizontal cylinder along with the shallower depths any layer can exist at in the first place makes for pretty rapid mixing. I try to fill all my OC tanks lying down even though I usually don't analyze or use them right away anyway.
 
My practise is to pump the first gas and leave it to cool. Work out my needed top up, do the second gas then and don't even look at it until the next day. I am getting very accurate mixes this way with a minimum of faffing.

Peter
 
I use my PP mixing program with Gerg2004 algorithm for calculations.
I simply fill in first gas, add the seccond and measure. Most times mix is spot on. Need to tell I lay down bottles when filling and use a 3 cuft compressor.

Main problem for differences in acchieved mix is different size of gass molecules and their compressibility differences.
They play the main roole while mixing Tx and Ean. Sure temperature play its role too....

Igor P


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