well, I guess since we don't have objective data I can't be sure, and I screwed up the math to boot, it was more like 30% less, but still substantial. My understanding of the theory behind radial scrubbers is that they essentially have a much larger surface area of exposed sorb to exhalled air, increasing the dwell time and therefore allowing the sorb to be used more completely with less chance of breakthrough. My understanding is that there is less chance of the reactant front migrating substantially during increased work loads. My understanding of an axial scrubber is that because dwell time can diminish exponentially with increased respiration that a much more substantial buffer needs to be calculated in terms of the migrating of the reactant front... like 50%, in order to prevent breakthrough co2, so we theoretically are throwing away roughly 50% of our scrubber each time on an axial scrubber.
I realize that the rEvo takes another aproach to addressing this issue and i'm also intrigued with it as well... it's my understanding that that 50% buffer is only occasionally used and likely for short durations and as the theory goes, splitting the scrubber in two and replacing half each time, advancing the second half the scrubber to the front of the line in the loop on the rEvo has a similar potential for sorb efficiency while maintaining a good safety margine. I get that theory and I think it's plausable as long as the margines aren't pushed too much.
In any case, I realize this is a hotly debated subject and there are diverging opinions about it and i'm only a little bit knowledgable about it, but given the dives and durations we were witnessing on the Prism, it seems only explainable by a dramatic difference in design efficiency of the scrubber. I"m guessing the meg version will have similar if not better performance and luckinly it will fit in my Copis!
g
Quote: (Originally Posted by
paulraymaekers)
Hi Gill, how do you know that the axial was to far gone compared to the radial??
IMHO, the advantage of radials lies in (perhaps) longer duration in cold water, and/or lesser WOB if you want a lot of sorb in your system
but in warm water, you don't need the radial for longer duration, because in warm water duration is more depending on amount of sorb you take with you, and much less the thermal system (radials compared to axials)
paul