User talk:RexxS/Rebreather
Anthony's edits
[edit]Thanks Anthony, I think your amendments all improve the draft, with the possible exception of the last part of SCR, which I'd consider too detailed for a summary (but which certainly would be appropriate for the Rebreather article). I think the key point there is that the decompression requirements on SCR will be similar to that on open-circuit using the same gas mix, although not identical because of the factors you mention. I'll put two possible versions below and see if anybody else will comment:
- Semi-closed-circuit rebreathers (SCR) recirculate most of the exhaled gases, but not all. Nitrox, heliox or trimix is supplied at a constant rate, balanced by exhausting gas at the same rate from the loop. They typically consume only one third the gas of open circuit. The SCR has the advantage of simplicity and only needing one cylinder. The amount and proportion of oxygen in the loop varies with the rate of flow, and with the rate of the diver's metabolism, and with any current rate of depth change. If the current supplied partial pressure of diluent is n bars, and if the diluent is nitrogen, that is equivalent to (12.5*n - 10) meters depth on open-circuit air for decompression calculation.
- Semi-closed circuit rebreathers (SCR) recirculate most of the exhaled gases, but not all. Nitrox, heliox or trimix is supplied at a constant rate, balanced by exhausting gas at the same rate from the loop. They typically consume only one third the gas of open circuit. The SCR has the advantage of simplicity and only needing one cylinder; but since it supplies a fixed fraction of oxygen, its decompression requirements are similar to those for open circuit using the same gas mix.
It's not crucial, but we'd have to dig out another source to verify the equivalence relationship you gave, as it's not used in the source (Shreeves 2006) that supports the rest of the text in that part. --RexxS (talk) 22:13, 12 February 2010 (UTC)