What affect does it have on WOB. That vacuum stuff is thick I thought. Only concerned I'd have is if it's an issue related to pressures associated with ccr vs oc as opposed to the dust, I wouldn't want to increase WOB
CCR and laryngospasm
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What affect does it have on WOB. That vacuum stuff is thick I thought. Only concerned I'd have is if it's an issue related to pressures associated with ccr vs oc as opposed to the dust, I wouldn't want to increase WOB
Industrial vaccum cleaner bags are made with 2 layers - I use one layer
They are also designed to allow a maximum of air through while containing the dust and dirt.
The JJ Scrim material is also hydroscopic, in use that means that a drop of water on one side of the scrim sheet will neither pass through nor wet the other side of the scrim sheet. If I knew what they were using I'd buy a couple of sq yards of the material.
Since I haven't been able to find out what they are using, my industrial vaccum cleaner bag is the best solution that I've found so far, and I don't notice any increase in WOB although simple physics tells me that it has to be there.
Michael
They are also designed to allow a maximum of air through while containing the dust and dirt.
The JJ Scrim material is also hydroscopic, in use that means that a drop of water on one side of the scrim sheet will neither pass through nor wet the other side of the scrim sheet. If I knew what they were using I'd buy a couple of sq yards of the material.
Since I haven't been able to find out what they are using, my industrial vaccum cleaner bag is the best solution that I've found so far, and I don't notice any increase in WOB although simple physics tells me that it has to be there.
Michael
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@michael-fisch appropriate term is hydrophobic.
Hygroscopic is when something absorbs moisture from the air.
The material is polypropylene nonwoven SMS material. Unsure of bond pattern or basis weight on your particular fabric, but that's what they're made of *I used to work for a company that was a big supplier of the stuff*
Hygroscopic is when something absorbs moisture from the air.
The material is polypropylene nonwoven SMS material. Unsure of bond pattern or basis weight on your particular fabric, but that's what they're made of *I used to work for a company that was a big supplier of the stuff*
silent running
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Something to think about regarding sorb dust: pre-breathing and getting moisture into loop from sorb activation will help cut down gas borne dust. To my mind, this is probably as good a reason for a pre-breathe as any other. I myself have never had this problem, except during training when I was using the coarse grade Sodasorb. I was very relieved when my instructor told me that there were better grades of sorb available...
Daedalus
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I'll tell the story. I was on a multi stage dive and dropping my second stage and about to go to the backgas. I took the stage reg out and had it in my hand while going to the backgas reg. In this instant I must have blasted a drop of water into whatever the layrngospasm sweet spot is. When I tried to draw a breath off my backgas reg no air was delivered. I immediately switched back to the stage reg since that was delivering gas a second ago only to find it too was not delivering gas. At this point I hammer the purge button on the stage and the gas is spilling out the exhaust tee while the mouthpiece is in my mouth but no gas is being delivered. Starting to freak now but I remember thinking if gas is coming out the exhaust tee this reg has to be delivering gas. So I am holding the reg into my mouth while depressing the purge and then all of the sudden everything is fine and I can breathe again. Go to the backgas reg and it breathes fine. Turn off my stage and drop it, the rest of the dive is uneventful. Never happened before or since.
If I had tried to go back to the backgas reg or started messing with the stage tank valve rather than holding the second stage in and pressing the purge while riding it out I dont know how my incident would have ended.
I strongly believe many reported events where a diver is found drowned with multiple available gas sources is a result of this, the diver tries to get a reg running, cant, maybe starts turning an "on" valve to "off" as panic starts to set on, or just doesnt have a reg in their mouth and inhales water when the laryngospasm episode ends.
I have had EXACTLY this same thing numerous times now on my rEvo. I can tell that it's my soft palate getting tired and then I start inhaling through my nose and mouth together.
In my case, I am pretty sure that it's just me wearing myself out (through inexperience) by doing 2 things in particular: One, letting my loop volume get too low and then trying to inhale against a very stiff ADV. And, two, having my CCR on my back in a suboptimal position which results in higher WOB than I should have, when I am in good trim.
As I have put more hours on the loop, it is happening less and less often. I am getting better at managing my loop volume, and I have made good progress in getting the unit in a better position on my back. But, man! Those first few hours involved many times of feeling like I was (sort of) gagging just trying to get a breath.
I have experienced described phenomenon once on a CCR as well. It took me weeks to figure out. My first reaction was to call the dive and inspect the unit carefully next day. No issue was found and I decided by then to try breathing in the workshop from the same scrubber, same gas to verify if probably something went wrong. (I was assuming contaminated DIL or scrubber)
After approx. 5 mins. it became much harder to breathe and it hit me even on land.
However, I stopped testing and decided to swap gas and scrubber. Same test- same result.
By then, I believed in kind of a medical condition- I drove to my physician and after all kind of checks over several days he wrote me fit to dive.
However, I told him that this was not good enough for me. Conducting demanding dives and being troubled by such problem under water is nothing I was to simply accept. By then, he was himself diving an AP Evo and he offered we could swap units and meet in the evening. We did, I took his Evolution he took my rEvo and there were no problems on either machine.
Day after, I was already happy about the result, I experienced same AGAIN during pre-breathing my unit.
This time, he came over and was able to whitness severe swelling in my throat. He administered Prednisolon (Cortison) and I was ok few seconds after, not able to re-create the effect.
He diagnosed it would obviously being an allergic reaction. Normally, the only thing I am really allergic to are cats- having a sealed unit I normally carry in a pelicase I saw no means for any cat even getting close to it. Further, after all the 'swapping units and parts' I used Virkon S every time and washed carefully.
So I was back on my trial and error.
The solution to the problem was finally to swap the moisture absorber. Turns out- even Virkon S did not inhibit the allergens (I normally include the absorber into the disinfection cycle). Upon investigation my best guess is, that there must have been a cat in one divebase I visited and hang the absorber overnight, probably thinking it was its playmate or so...
Lessons learnt (to me):
* Allergens may multiply effect if trapped inside the loop
* Virkon seems not to disable allergens
* Cats are evil creatures and love moisture absorbers
I am unsure if this may help in any way, but I decided to write it down. If this can be helpful to at least one person in future it was worth the job
After approx. 5 mins. it became much harder to breathe and it hit me even on land.
However, I stopped testing and decided to swap gas and scrubber. Same test- same result.
By then, I believed in kind of a medical condition- I drove to my physician and after all kind of checks over several days he wrote me fit to dive.
However, I told him that this was not good enough for me. Conducting demanding dives and being troubled by such problem under water is nothing I was to simply accept. By then, he was himself diving an AP Evo and he offered we could swap units and meet in the evening. We did, I took his Evolution he took my rEvo and there were no problems on either machine.
Day after, I was already happy about the result, I experienced same AGAIN during pre-breathing my unit.
This time, he came over and was able to whitness severe swelling in my throat. He administered Prednisolon (Cortison) and I was ok few seconds after, not able to re-create the effect.
He diagnosed it would obviously being an allergic reaction. Normally, the only thing I am really allergic to are cats- having a sealed unit I normally carry in a pelicase I saw no means for any cat even getting close to it. Further, after all the 'swapping units and parts' I used Virkon S every time and washed carefully.
So I was back on my trial and error.
The solution to the problem was finally to swap the moisture absorber. Turns out- even Virkon S did not inhibit the allergens (I normally include the absorber into the disinfection cycle). Upon investigation my best guess is, that there must have been a cat in one divebase I visited and hang the absorber overnight, probably thinking it was its playmate or so...
Lessons learnt (to me):
* Allergens may multiply effect if trapped inside the loop
* Virkon seems not to disable allergens
* Cats are evil creatures and love moisture absorbers
I am unsure if this may help in any way, but I decided to write it down. If this can be helpful to at least one person in future it was worth the job
Nicool
Contributor
Hi guys,
The issue described by the OP happened to both my wife and myself on our rEvos, several times over years, and happened to me more when i was a beginner.
To me, this has to do with the breathing challenge cause by back-mounted counterlungs when you’re diving very flat or slightly head down for too long.
Happens a lot to us when we photograph citters hidden between rocks, worse if struggling vs a current with drysuits lifting our feet up.
Typically avoided by watching our position, and the effect can be reduced/stopped by rising chest up a bit, paying attention for a few minutes.
This topic was discussed in rebreatherworld in a good thread where someones reffered to this feeling as « having the snorts ». Hope this helped.
Cheers
Nicolas
The issue described by the OP happened to both my wife and myself on our rEvos, several times over years, and happened to me more when i was a beginner.
To me, this has to do with the breathing challenge cause by back-mounted counterlungs when you’re diving very flat or slightly head down for too long.
Happens a lot to us when we photograph citters hidden between rocks, worse if struggling vs a current with drysuits lifting our feet up.
Typically avoided by watching our position, and the effect can be reduced/stopped by rising chest up a bit, paying attention for a few minutes.
This topic was discussed in rebreatherworld in a good thread where someones reffered to this feeling as « having the snorts ». Hope this helped.
Cheers
Nicolas
The issue has gotten much better and seems to be a combination of issues. We changed how we fill our sorb cans. We now have a fan blowing and pour from up high. My wife also vacuums out her canister before refilling it and also vacuums from the outside after filling. Those changes have made a world of difference so I think the dust was the main issue. She also started taking zyrtec a day before a dive and that helped a little more, though we aren't sure it's not placebo effect. Living in florida, I have chronic pollen allergies and I do find that being on the loop vs oc is more annoying with allergies. Because of the pressure gradients I feel more of the crap in my sinuses get moved around. It can be a little annoying. We're not sure if she had a a little of that too, but mainly think it was the dust. It's amazing how much less dust there is when pouring with a fan blowing on high.
Sven Becker posted this on CCR Explorer as a solution to sorb dust saying to slowly let the sorb fall with the vaccum cleaner on at about 1/2 power. Also to transfer the vaccumed sorb before the container gets more than 1/4 full.
I tried it, I like it and I will continue to use it.
Michael
I tried it, I like it and I will continue to use it.
Michael
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