Dolphin spares into a ray = ccr

[Addthe bad]

Please tell me when I go wrong:

On the dragger dolphin  (Crashed and burned) I have the following ports:

32%
40%
50%
60%


plus one flush. Normally the flush and the chosen port connect up to the first stage.


To close the system:

There is the under-pressure valve that I would connect to the dilluent.  This allows me to flush at any time just by breathing out through my nose


Up to this point we are talking scr


I need a 100% port so that it is pushing in 1l/min (I've been told you can now get these fron drager via apex)

NOW the scr becomes ccr as there is no flush and the o2 is going in.

I’m resting at 6m so all is well.

I drop down to 20m.  the under-pressure valve kicks in as the lung collapses filling it with dilluent (Plus of course 100%  O2 at 1 l/m)

I look at my ppo2 and realise that I’ve been working harder than I thought as at 20m it reads 0.8.  I have a connector from my 1st stage o2 into my 60% port with a valve  so I press it to bring my ppo2 up to 1.3…… but I press it for too long and it goes up to 1.6……. Ah! So I breath out through my nose to pull my 21% dilluent in…. That’s better – it now reads 1.25 and I’m not going to try and adjust that.


I swim along and it is now at 1.10 so another LITTLE squirt of the 60% port and up it goes again to 1.35.  that’s better!


Time to ascend.

PPo2 1.30.

I rush to 10m (Bad diving technique admitedly) and that halves my ppo2 to 0.65. The usual scr overpressure dumps the excess

I sounds low but it’s still the same as 32% nitrox..  Still I have been down an hour so I stop at 10m and give a sqirt of o2 in the 60% port to bring it back up to 1.2.  I do 3 mins at 10m, and then come up without adding any more o2 to give me a leaving ppo2 of 60%





Things to bear in mind:

I already read my ppo2/ mix from a vr3 into the oxygauge port
I need another ppo2 display (PPO2.com) .  What do I do with the other sensor?

Drill a hole in the scrubber and using an IP68 gland make it water tight



Seems too easy- Where's my mistake?

[steve-k]

Q, what hapens if your metabolic o2 consumption is 0.7lpm?
will you be constantley flushing the system, using up your dilutant

had a few links for pages where people have converted the drager to a ccr, but just had to re-format and have lost them, do a serch and you should find some

i think they used an adjustable valve that they set to there own rate, a bit like the kiss system

you can get a fitting to connect you vr3 directley to the bag, then you can ust the other for the drager sensor

[Addthe bad]

I'm already there with the VR3 connector but I'd not considered inspiring less that 1 l/m   Hmmm.


Back to the drawing board