swisstrav:
using a compensated regulator does not help in any way. it worsens the situation. once again due to increasing intermediate pressure you get also a higher gas flow. thus a higher ppo2.
Please allow me to be more specific with my question:
Assume: -Dive plan: 300 feet for 30 minutes, plus deco
-all appropriate deco to be done on OC stage bottles
-Drager dolphon used for depths from 200 to 300 FSW
-Drager with 32% orifice (it rips)
-Compensated 1st stage starting at 180 PSI at surface
-120 cubic feet of 12/60/28 mix feeding the SCR
-408 Sofnolime (less resistance than 812)
-VR3 computer with integrated O2 sensor
Thus no matter how darn fast the gas flows, it would be physically impossible to get over 1.2 PO2 (the main objection I have heard so far).
Also, with I ripping flow, I would think it would be hard to get below .3 PO2 since you are only using the thing below 200 FSW.
I am not interested in comments on logistical problems of managing stage bottles. I am not interested in comments on decompression requirements. I am not interested in comments on how to bail while in the 200 to 300 feet range on the RB. And finally I understant that CCR is specifically designed for this type of dive (maybe I need to go find a Kluger's board.)
I am interested in comments on what might initiate a bail out in the 200 to 300 foot part of this dive while on the modifed Drager.
Feel free to throw in barbs, because I know I am pressing the issue. But if this would work, it would save me money.
Cheers
Batman
The one BIG issue with a Dolphin whether it be one used as an SCR or modified to a CCR using a KISS orifice..
The loop is not very flood tolerant.. Sh*t happens, a LITTLE water in the loop (not uncommon) your off it.. there is very poor water trapping or evacuation abilities.. IF you switch to a micropore disposable cartridge (and larger scrubber) you have a bit more leeway with a partially flooded canister.
On a RB designed for deep use, water traps are an intergral part of the design.. On an Inpsiration you can Isolate several liters of water before it becomes a problem.. On a CIS you can totall flood the loop and recover... The Prism and Megladon can also isolate/dump water... but agian these are all CCRs.
If you are running the flow wide open, with practice your other tanks could be fed into the loop, but starting/ending OC is safer.
Also the IP of a drager is 450psi it will work in the sonic range at 300fsw, the no compensated regs on a kiss first of all act like restricted orifices not sonic and they are based on standard 1st stages with the pressure port blocked, thats why they stop at around 300 fsw - when set at 135psi (150 psia) the pressure at 300 psw is about 148 psia