liberty rebreather scrubber time.

[PfcAJ]

That seems just a bit overly dramatic. Yes, it is bad to unpack and repack sorb. Never ever do that! But's it's not instant death either. A CO2 hit can be dangerous but it's not like hypoxia where you just pass out. It could trigger a cascade leading to panic, but it can also be recovered safely.

I've had a CO2 hit before. My experience was that I did one dive on fresh packed sorb, then drove several hours to another location and did another dive the next day. In the first 10 minutes of that dive I started to get very irritable and frustrated over nothing. Then I started breathing faster. I quickly realized my loop was bad and bailed out. On OC bailout stayed put for a few minutes and got my composure back. I did a safe ascent with my buddy and all was well.

I suspect that some channeling occurred in my scrubber during the drive which allowed for a breakthrough. This was on a Sport Kiss about 10 years ago. That unit's scrubber does not have a spring loaded cap holding the scrubber in place and it's a single chamber canister. I have since moved to a Kiss Spirit with two canisters with a simple cylinder shape and tight spring loaded heads. A much better design.

Id think that at a low workload you might not even notice. Have to work a bit? Now that reduced scrubber efficiency could cook your goose.

 

[davehicks]

Id think that at a low workload you might not even notice. Have to work a bit? Now that reduced scrubber efficiency could cook your goose.

I had a very low workload. I had just dropped on a wall with no current. In just a few minutes I was feeling anxiety and starting to hyperventilate. I understand these are pretty common reactions.

 

[PfcAJ]

I had a very low workload. I had just dropped on a wall with no current. In just a few minutes I was feeling anxiety and starting to hyperventilate. I understand these are pretty common reactions.

Im curious as to how much of your scrubber time you had used.

But I guess I should have stated in my above post that a mixed (used and unused granules mixed together) might go undetected depending on workload.

 

[davehicks]

Im curious as to how much of your scrubber time you had used.

But I guess I should have stated in my above post that a mixed (used and unused granules mixed together) might go undetected depending on workload.

I had loaded fresh scrubber the night before and then done about 1 hour of diving. Then I loaded everything up and drove about 4 hours. The next day I had a break through on the first dive within minutes. For sure it was channeling from the agitation of the drive. The scrubber should have been good for 3-4 hours in 50F water temps.

 

[PfcAJ]

I had loaded fresh scrubber the night before and then done about 1 hour of diving. Then I loaded everything up and drove about 4 hours. The next day I had a break through on the first dive within minutes. For sure it was channeling from the agitation of the drive. The scrubber should have been good for 3-4 hours in 50F water temps.

Descending on the scrubber design if it’s laid down on its back that’s a possibility.

 

[Heat Miser]

I had loaded fresh scrubber the night before and then done about 1 hour of diving. Then I loaded everything up and drove about 4 hours. The next day I had a break through on the first dive within minutes. For sure it was channeling from the agitation of the drive. The scrubber should have been good for 3-4 hours in 50F water temps.

How much bail out did you go through. and from what depth? and how long did it take to fully recover at surface?

 

[ChuckP]

When you guys say "channeling" I pictured a gap or area of no sorb that gas would easily pass thru verses the sorb. Is channeling also a path of used up sorb?

If gas is passing from outer to inner area, is it somewhat of a used up area of sorb on the outer surface that gradually moves inward as the sorb is used?

 

[tbone1004]

When you guys say "channeling" I pictured a gap or area of no sorb that gas would easily pass thru verses the sorb. Is channeling also a path of used up sorb?

If gas is passing from outer to inner area, is it somewhat of a used up area of sorb on the outer surface that gradually moves inward as the sorb is used?

What @davehicks described is a gap of no sorb that happens due to either bad packing of the scrubber or vibration that causes weird settling.

What we were talking about with repacking a scrubber is a path of used up sorb. On radial scrubbers that is out to in, on axial it is top to bottom. Axial is a lot less likely to channel

 

[rddvet]

Dont dump the sorb out and repack though. Bad news bears.

that I would never do. If the lid comes off the sorb canister the sorb goes in the trash

 

[davehicks]

How much bail out did you go through. and from what depth? and how long did it take to fully recover at surface?

It was unremarkable. I had dropped to maybe 60' when I had the issue. I surfaced on 21% OC from my 40cf bailout. I don't typically dive below 100' or plan on deco. I stayed there for a few minutes recovered off the loop and went to the surface. I don't recall any issues or recovery needed at the surface. I changed my scrubber and did a couple more dives that day.