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Aloha, sorry for the delay in getting this to you folks, been too busy .. these are dry tests to see just where we are on o2, and some notes of stuff we noticed along the way. we are going to add a sensor and monitor for wet tests, will post on those when we are finished... (don't hold your breath) :-) fieno tests maintenance prep time averages about 21 minutes, this includes complete break down and washing all parts (even the counterlungs). test one (hypoxia) dry test, o2 sensor installed in the right counter lung, sitting on stationary bike (at least i could <see> the ocean out my window). :-) started with 20.9% o2, breathed at rest with gas turned off, freshly packed canister. 39 breaths over 5 minutes, stopped at 16.4% o2 symptoms of hypoxia euphoria, not like narcosis, much smoother and more comfortable. fingers turned white, head ache (continued for 25 minutes after test), trouble concentrating on the clock (analogue), also trouble maintaining the count of breaths, lips felt a funny, maybe numb a little. second test dry test, started on bike with 82 bar in cylinder, 39.9% nitrox. Calibrated sensor (in right counter lung) at 20.9 o2. within one minute of turning on the gas the miniox read 26.6, i started riding moderately (18mph) for the first and second minutes... i will chart out the time below; minutes o2% load on subject 1 26.6 rest 0mph 2 24.5 moderate 18mph 3 23.8 heavy 27mph 4 22.6 '' 28mph 5 20.4 '' 28mph 6 18.8 '' 27mph 7 17.3 '' 29mph first time i noticed the heat from the absorbent, light heat. 8 16.8 '' 23mph slowing more heat from absorbent here, warm but it feels good, no taste at all. 9 16.2 moderate 18mph 10 15.6 rest 0mph one purge sightly (one second) on the mouth piece lever 11 18.7 rest 0 12 22.7 light 5mph 13 21.5 '' 4mph 14 21.8 '' 3mph 15 22.5 '' 5mph more heat here, slightly getting warmer, feels good, no taste. 16 23.9 '' 5mph 17 23.6 rest 0 stop gas down to 48 bar condensation; almost none, very slight (one small drop every square inch) on conter lungs, no pooling. third test dry test on bike as in two, o2 sensor in left counterlung this time, started riding as i turned on the gas (40.1% nitrox). this is probably the most accurate real life scenario as in a constant flow unit you would turn on the gas as you hit the water. started with 49 bar in cylinder. minutes o2% load on subject 1 20,9 light 11mph 2 22.6 moderate 17mph 3 24.7 '' 18mph 4 22.4 heavy 26mph 5 21.8 '' 29mph 6 19.4 '' 28mph 7 17.5 slowing 25mph 8 16.7 .. 23mph 9 16.3 light 12mph 10 15.8 rest 0 11 15.4 '' 0 heat again, no taste, the warmth feels good again. 12 17.2 light 10mph 13 18.1 '' 11mph 14 18.4 '' 10mph 15 20.1 '' 14mph 16 21.4 moderate 18mph 17 23.2 '' 19mph 18 23.7 '' 18mph 19 25.0 '' 18mph 20 26.5 climbing 20mph 21 27.3 heavy 25mph 22 26.2 '' 29mph 23 22.8 '' 28mph 24 18.4 slowing 25mph 25 16.9 moderate 19mph 26 16.1 light 12mph 27 purge one second 19.8 '' 10mph 28 21.1 rest 0 29 more heat noticed 22.4 '' 0 30 25.8 walking 3mph 31 gas runs out 23.6 '' 3mph 32 23.0 '' 3mph 33 22.6 rest 0 34 21.4 '' 0 35 21.0 '' 0 36 20.9 '' 0 37 20.6 '' 0 38 20.5 walking 3mph 39 20.1 '' 3mph 40 19.7 '' 3mph 41 19.7 stairs 4mph 42 19.4 '' 4mph 43 19.2 '' 4mph 44 18.9 walking 3mph 45 18.6 '' 3mph 46 18.4 rest 0 47 18.4 '' 0 48 18.4 '' 0 49 17.5 '' 0 50 17.2 walking 3mph 51 16.9 '' 3mph 52 16.5 rest 0 53 15.9 '' 0 first signs of hypoxia, a little euphoria 54 15.4 '' 0 stop condensation; less than two table spoons found in canister area, none in counter lungs except small droplets on bag. notes; the canister holds exactly 16 ounces of absorbent (two cups). we pack our own and use sofnolime, from a 4.5kg plastic bottle (looks like a gallon jug). granule size 8-12 mesh, indicator white to violet, a very few granules turn color, after one hour they change back to off white. i can see where this could be a problem. (note that we have seen a slight trace of color in the counterlungs, maybe from dust, makes me wonder if my lungs are glowing as well) :-) also note that this product and the one that nissan prepacks has little or no taste, where the dragersorb 400 is more noticeable, these products are grannular where the dragersorb is little pressed pellets. mouth piece does not open fully unless it is positioned properly, this gives the impression of a full counterlung or other problems. we had this happen on previous dives and thought the hoses were crimped or we had water intrusion causing the breathing resistance to increase.. we found out that it is the mouthpiece an is easily avoided. we also found out that on the longer dives the mouthpiece will push against your chin and get somewhat uncomfortable, this is most likely due to the small size of the unit compared to us.. we have been told that the units do come in larger sizes.. remember to watch what you eat before you dive a rebreather, if you burp you get to breath it for a while.. unless you exhale thru your nose. velcro on cummerbund is on the wrong side, minor but you notice it. one nice feature is the purge button onthe mouthpiece, this puts gas directly into the loop when you need it.. with a monitor and o2 sensor one could be safe under any load just by pulling the lever when needed. of course the gas wouldn't last as long. i can see adding a pure o2 bottle for gas tweeking to extend the duration of the unit when under stress from current and such. that's all for now.. dp
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