Rebreather World - View Single Post

frankstoop · 14th May 2008, 15:09

Quote: (Originally Posted by davy)

Like Frank mentions, there is the "magical factor" 2.5 which is valid for a 4% surface O2 consumption and 1:10 bellows which matches my situation very well.
This results in a quite simple formula that can even be used on-the-fly.
On verification during actual dives it was spot on at predicting pO2.

The pO2 drop is actually the partial pressure of the inert gas / 2.5
to know the pO2 during the dive, just subtract the pO2 drop from the pO2 you would have on OC.

I created a little excel sheet to easily play with it and learn.
the user interface is not that great, but if you want I can send it...

Also there is the V-planner which incorporates a full blown decompression planning for pSCR which works well.
Very cool to compare "actual" profiles Vs. OC reference plans.

i agree with you davy. Just calculate this ppO2 and subtract it from actual ppO2. BUT, ONLY in STABALIZED conditions. On descend, there is lots of gas injected in the belows and the ppO2 drop can decrease to 0. On the other hand on ascend ( if not right operated ) there isn't any injection and the ppO2 drop will increase rapidly.

regards, Frank

14th May 2008, 15:09	#14 (permalink)
frankstoop New Member Current Rebreather/s: Other SCR Other Rebreather/s: Other SCR Join Date: Nov 2006 Location: holland Posts: 3	Re: RB80 Math ? Quote: (Originally Posted by davy) Like Frank mentions, there is the "magical factor" 2.5 which is valid for a 4% surface O2 consumption and 1:10 bellows which matches my situation very well. This results in a quite simple formula that can even be used on-the-fly. On verification during actual dives it was spot on at predicting pO2. The pO2 drop is actually the partial pressure of the inert gas / 2.5 to know the pO2 during the dive, just subtract the pO2 drop from the pO2 you would have on OC. I created a little excel sheet to easily play with it and learn. the user interface is not that great, but if you want I can send it... Also there is the V-planner which incorporates a full blown decompression planning for pSCR which works well. Very cool to compare "actual" profiles Vs. OC reference plans. i agree with you davy. Just calculate this ppO2 and subtract it from actual ppO2. BUT, ONLY in STABALIZED conditions. On descend, there is lots of gas injected in the belows and the ppO2 drop can decrease to 0. On the other hand on ascend ( if not right operated ) there isn't any injection and the ppO2 drop will increase rapidly. regards, Frank
(Offline)