Rip Quinby did a lot with air/zinc batteries a bunch of years ago. See here:
The Zinc-air O2 sensor debate
Funny that he's a local guy here and now works professionally rebuilding a certain antique airplane, the North American Navion (which I happen to own a sample of as my family cruiser....) Small world. AFAIK he's not working with rebreathers now.
The time response being long in the sensors as described is not a huge issue.... the loop PP02 does not vary enough in the short term for long response to be an issue. Bottom line: Over the 30 second period *who cares* what the PP02 is, as long as it's viable? With normoxic diluents and a basic setpoint of 0.7 (the old Electrolung PP02) it's REALLY hard to get into trouble in the 30 second time frame. Who cares if the solenoid fires a few extra times in that period? "Maybe" the PP02 will rise to 0.9.......Electrolung designer Walter Stark used what he had.... and he did damned good. He's forgotten more than most of us know, and simply smiles and does not answer when asked. He's the one who taught me that if you cannot design and build it without help, you ought not to be diving it.
Bill Sewall did some experiments after reading Rip's work and he can comment. Come on cstmwrks! We know who you are, destroyer of oil-saturated pony bottles, diver of arctic lung, and vulcanizer of counterlungs and all.... ;-)
For those who never were a part of the "old" NW Rebreather list, when there were just a few of us as part of the family, here's the sort of debate that we enjoyed:
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Will Smithers writes:
Ripley, I am doing my best not to be snide here, but your enthusiasm and emphaticism has wasted over 20 hours of my time at this point, and I'm not wasting much more on this topic, which has now been exhaustively covered, as far as I'm concerned. But, because I am willing to grant you some small margin of doubt, I will waste up to three more hours on this subject. Please fax me your drift-compensating circuit, and I will run a series of chamber tests using your own design.-Will
And Will has now fairly well refuted the theory and backed up his results. And Rip replies:
Sincerest Apologies Bill, I spent over 600 hours of my time developing a reliable Rebreather which works quite well for me. You've got a lot of hours to go. Keep experimenting, you'll get there. Anyone who believes that verification of research is a waste of time is himself a waste of time. Sorry to have hampered your social life. Regards, Rip
At this point, Lee sums up Rip with the following:
Arrogant sucker, isn't he?. . . Lee
And the final word.....
Who's the dumb Fu** that recommended the zinc air batteries? This is the single stupidest thing I have seen on here, and that is saying something!!!
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Sheesh..... who else but Bill and myself remember these circa 1998 debates? Rebreather Tinkering has come a long way since those days, when the total "non-government owned" CC Rebreather population was probably sub-100 worldwide with 30-ish of those being Mark-15's built up by Kevin. I sure do miss 'em..... I cannot swing a cat now without hitting a new rebreather "expert".
Dave (defying death by bad-gas since 1979)