Extend Air scrubber cartridges ?

[caveseeker7]

jepuskar once bubbled...


The sales rep for Extendair told me that some customers are reporting 6-8 hour durations in 80 degree water. He said tests were going to be performed so they can verify this and thus update the durations based on water temp.

He also stated that they always stick to saying 2 hours because they know that works..until further documentation comes out he does not recommend anything over 2 hours.

The sales rep ... 8 hours, yeah, right. In shallow, warm water using a Mk15 or RB80 maybe, but with the cartridge in a Dolphin? I rather doubt that. Think about it: There is less absorbent in the cannister, because a) the cannister is round rather than oval as the stock scrubber, and b) the absorbent is mated to a grid of some sort, I asume a plastic, which the is 'rolled up' with still more space in between ... .

Somehow that adds up to less scrubber time rather than more. Hence 2 hrs rather than 3 or 4.
The idea is good, the stuff handles very clean and easy. If I have to change scrubber, especially on a boat, I'd rather do it this way. But not or that price ... . And for extended range it just isn't giving enough time.

By the way, am I the only one worried and suprised that they're only running the tests NOW ? That stuff's being sold for a while ... :upset:

 

[caveseeker7]

saturated once bubbled...
I haven't been able to find any published data on any of the manufacturers websites. If I'm wrong please post links.

Published data on scrubber times?
Manufacturer data or 3rd party data?

Steammachines has the NAVY test results on their website as a .pdf file.
The rest of them, as far as I know, state their own data (or that of the CE certification in case of the Ambient Pressure and Dräger).

Haven't checked Aqualung/Dräger's US pages, but Aqualung revised the the scrubber times for the two Dräger units on their German page. A screenshot courtesy of my Mac below, but it's obviously written in German.

Translates into: Absorbent Information
In Europe (incl. Egypt) new scrubber duration times (DiveSorb) are applicable for Dräger rebreathers, measured with a minute breathing volume of 30liters/min:
Dolphin (2,25kg absorbent): extended from 3 to 4 hours
DrägerRay (1,125absorbent): extended from 70 to 110 minutes

Makes ExtendAir's rating worse, and the US rating kind of a rip-off (as you're supposed to buy 25% more dive sorb than the Europeans :upset: )

 

[saturated]

Sorry was rambling abit.

"I understand that using an ExtendAir CO2 adsorbent for a time period longer than stipulated by the rebreather manufacturer or otherwise failing to follow any instructions relating to the operation or use of the rebreather or the ExtendAir CO2 adsorbents may result in substantially increased risk of injury or death to myself."

In that statement ExtendAir has said that you cannot use their scrubber longer than stipulated by the breather manufacturer. To my knowledge no breather manufaturer has tested the ExtendAir in their unit and provided results. This is not likely to ever happen.

 

[caveseeker7]

saturated once bubbled...
To my knowledge no breather manufaturer has tested the ExtendAir in their unit and provided results. This is not likely to ever happen.

In Europe's required CE testing the absorbent is tied to the certificate.
In other words, whatever absorent(s) was or were used to get the certification is/are the one(s) the unit is/are legit with. As DiveSorb is a Dräger product I'd say slim chance the cartridge will ever be certified (unless the absorbent coating is Divesorb). Same for the Inspiration and Sofnolime. Part of the certification.

OMG has on their website an upcoming CCR, the Nemesis, a prototype of which was at DEMA last year. It is supposed to be certified and used with the cartridge. If that is the case, the Azimuth models may well get recertified for it, too. The welded steel cannister is probably more expensive to produce than the plastic cartridge container, and isolates less. Nicely placed weight, though.

 

[saturated]

Sorry, I'm running on very little sleep at the moment.

well put, in all my babling I think that is the point I was tring to make.

 

[scubachris]

I haven't used the extend-air but did see it at DEMA. As a diver and PADI/TDI rebreather instructor who also uses (my personal) Draeger Dolphin very frequently my concern is cost and availability. Living in the US Virgin Islands it's pretty each to get SodaSorb. But it's costly to have the extend air shipped down, bigger to store, compared to a 5-gal bucket.

Something to think about if you are traveling with your rebreather or plan to live someplace that some things are not as accessible.

Lastly the cost justification just doesn't play out to their ease of use advertising. It's not that hard to fill you canister, tap it abit, top it off, etc. Even students after a the first couple of times only take a few minutes. You've got to dispose of both either way so disposal isn't an advantage one way or the other.