Question unused scrubber…

[Enevoldsen]

Hi, we planned a dive today, but had to cancel just after i was finished prepaering my SF2. We plan to dive again saturday… Is is safe to use the same scrubber, if i leave it sealed ind the rebreather or would you discard it and use new scrubbermaterial? It has been pre breath . thats all….

 

[pk2782]

Personally, I would not leave it in the breather. I would pull it out and store it in a sealed bag outside the unit. That is based on my experience on the JJ. Leaving it in the breather will not be good on the oxygen sensors for starters.

 

[grantctobin]

Personally, I would not leave it in the breather. I would pull it out and store it in a sealed bag outside the unit. That is based on my experience on the JJ. Leaving it in the breather will not be good on the oxygen sensors for starters.

What does an air filled loop with dry scrubber have anything to do with oxygen sensor life?

 

[Enevoldsen]

just what i was about to ask. The sensors in my unit sits in the head, all time, until they are prone to change. My main concern is if the scrubber will still be usefulle after 2-3 days, sealed in the unit?

 

[Whitrzac]

Personally, I would not leave it in the breather. I would pull it out and store it in a sealed bag outside the unit. That is based on my experience on the JJ. Leaving it in the breather will not be good on the oxygen sensors for starters.

Citation needed...

Completely safe to leave it unused on the breather. If it was used you would want to leave it off the unit while the condensation evaporates.

 

[lostsheep]

Personally, I would not leave it in the breather. I would pull it out and store it in a sealed bag outside the unit. That is based on my experience on the JJ. Leaving it in the breather will not be good on the oxygen sensors for starters.

What exactly is your personal experience on the JJ that you speak of?

What do you think sofnolime is reacting to that could create a damaging byproduct?

 

[macado]

I hate to make generalizations but in this case I will. It's safe to leave an un-used scrubber in your sealed rebreather. It probably happens every day all around the world, dives get canceled, unit stays sealed and built until the next dive at later date.

As long as the unit is sealed, disinfected, clean of water and "lung butter" from previous dives there is not really much that is going to happen. I probably wouldnt do it for a month but a few days or even a few weeks is not going to hurt anything. Having said that, I've left un-used scrubber in my rebreather for a few months before. No issues but I just dont make a habit of it.

In situations where the scrubber is partially used then I would take it out of the rebreather so the rebreather (cells / counterlungs) have time to dry. I would store the scrubber in a dry bag until I'm ready to re-assemble the unit.

TL;DR - You're over thinking it. Keep it sealed, go diving.

Storing partially used scrubber: Storage of partly used closed-circuit rebreather carbon dioxide absorbent canisters

 

[bubblemonkey2]

The scrubber is probably safe in there, but for checklist purposes it might be a good habit to take it out, put it in a clean plastic bag, and then just redo the whole build checklist again, step by step but with the scrubber already packed (check it again though)

Disclaimer this is for a fairly small (70kg) diver with very relaxed trim, good buoyancy, and very little exertion (often DPV dives), but:

Have on several occasions put 6+ cumulative hours on a 2.5kg scrubber spanned over multiple days and lower-consequence (shallower/easier) dives (up to five) spanned over up to a month, with the intact canister always removed, wiped dry, checked/snugged up, and stored intact (never repacked) in a plastic bag between dives. A well-rehearsed BOV routine and shallower dives as the duration steps up, but no signs of hypercarbia thus far. Sudden exertion and breakthrough on an old scrubber is an important risk factor, pre-emptive bailout might be advisable in that case.

Most scrubber material has a nominal use rating of 150 L CO2 per kg, which is about 4 to 8 hours at a steady (lower exertion) O2 metabolic rate of 1 to 2 L/min. But you could overexert or panic and overwhelm the scrubber at any point during a dive, even if it's under 3 hrs of cumulative use.

 

[davehicks]

First off, many divers will set up and test their unit a day or two before going diving. The scrubber can sit in a sealed rebreather just as comfortably as a sealed plastic keg. If you have not even dove the unit, then you don't need to disassemble anything, just do your pos/neg tests before taking it out to dive again. No issues there.

I routinely go out and dive my CCR (Kiss Spirit) for perhaps a 1-hour dive. I come home and rinse down the whole unit with a hose, run water through the loop, spray in some steramine, and then let the loop dry for a day or two. The cells are exposed so it can dry out. Then I reseal the hoses and leave the whole unit ready to dive another day. The next dive might be a couple of days later, a couple of weeks, or even a month.

There is no problem with this so long as everything it cleaned and safely stored before the next dive. I've been doing this for 15 years with no problems.

 

[Enevoldsen]

Thank you - for all the answers