mixing eCCR and mCCR for a best world?

Marc T

Between mCCR and eCCR I think there is a place for a system mixing “the best of two worlds” and the question is why so few people ( and more specialy home builders ) does follow this way.
If you ask why not me the answer is not enough time , to much tumbs in my hands , not at all electronics capability

How do I ( and certainly some others )see that working together ?:

- classic mCCR with CMF and two or better three sensors and O2 display
- one of the cell is ALSO used to control and fire a solenoid valve only for a quite low ppo2 ( something between 0.4 and 0.9) with a buzzer to make you awake again

Advantages:
- quite simple and non expensive
- reliability: no voting logic ( Im always waiting for sensors fusion )
- always have an eye on the sensor witch is able to fire the solenoid so the system is safe even without voting ( your brain do that better )
- parachute system in case of high task loading or extrem silty situationor emergency with buddy for example, you PERHAPS turrn mCCR off and you trust in your sensor that you was chekking few minutes before
- long life batteries because few ( no )solenoid firing in a normal dive
- possible extending depth capability

Any thought about that?

Mark Chase

Surley you can dive any ECCR like that. Just put the set point at 0.7 and run the unit manualy at 1.2 1.3.

The solinoid will not fire unless you drop to 0.7, voting logic dosent come inot play and you get sensor readings on the hand sets.

ATB

Mark Chase

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See my "Doing It Chasey" video where I'm locked into a padded room, naked, with two ball bearings and within an Hour, I manage to lose one and break the other!!!

Kevin Juergensen 16/11/08
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Marc T

Yes but its a bad m CCR ( no CMF ) and expensive system but of course adding a CMF valve could be a way if you own an inspiration and dont trust anymore in is voting logic could be a good thing too

paulraymaekers

2 systems to verify
2 systems that can go wrong... (am I diving CMF or am I diving ECCR at the moment) (more failure points)
when somethings goes wrong... wich system goes wrong...

what MP to use 11/12 bar for CMF a bit high for ECCR.. (using 2 first stages...)

I studied it a bit: but just to make an oxigenparachute on 2 cells: (with a 2-cell rEvodream easy to do) no voting logic at all: simply adding values of both cells and if value <0.4 inject 3 seconds with 3 seconds interval:
suppose one cell would fail complete (0.00) then the max it could give you is 0.8
as independant second system another rEvodream/hud: this is what we use on the test-rEvo's with a HH: the hud on the rEvodream tells you what the HH gives you.

but until now: we consider it more risky than advantage (stuck open valve..)

regards
paul

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dave t

I fitted a kiss valve to my inspiration and actually I quite liked it. The kiss valve ran the po2 and the electronics (I had only one handset) sat as backup and help to hold po2 on ascent.

Is it more to go wrong! well maybe but its also a backup system if its configured simply.

But it does remove the one IMPORTANT thing about kiss style rebreathers and thats the divers Attitude, with a kiss style Rebreather you KNOW the only thing in control is the diver!

Digger

Brett at Divelife had a replacement for the inspo button which you could screw a kiss valve into, with manual add on it. It would reduce the number of times the solenoid fires, why not just run the inspo at 0.7 (you can do this can't you?) and use it kiss style to stay at 1.3?

Problem is you're depth limited as you are with a kiss as a result, and the solenoid would get little if any use, so you'd have to treat it nice to make sure it would work when required.

Digs.

jeff h

What about an electronic controlled needle valve?

This would be more of a total eccr with a twist to it. A servo adjusts the valve to match the divers metabolic rate with O2 is constantly flowing into the system.

Probably would require very little diver input and would be harder to monitor the unit with no solenoid firing.

narked at 90

digger mate dont for get i sell them to! they are instock and ready for shipping

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Digger

See what I mean about having a beer more often! Will be down soon, I got my new 3s yesterday so you can have the tins back asap.

So Brett, or John. Toss a coin, they're both mates...

uri

Technically not problematic but not conceptually pure. So what you might say, if there's a place for it?

I view Rebreather divers as falling into two distinct camps. Those who want full control and to rely on themselves and those who ideally don't want to know unless there's a problem. Usually compromises are made on the latter and some degree of active monitoring required but the Diver doesn't want to but accepts some degree of monitoring as safe due to technical limitations of Rebreather equipment.

Those IMHO represent the two 'pure' camps.

What you're suggesting crosses the boundary between the camps. It doesn't work for eCCR divers because they accept regular monitoring but don't want manual control except under unusual conditions. Does it work for mCCR divers? My guess is that it takes away the very basis for their happiness with their choice ie they are in control.

I wonder what percentage of the KISS style market would seriously consider an approach based on losing that?

U.