[PSUBS-MAILIST] CO2 absorbent test

[Sean T. Stevenson via Personal_Submersibles]

You could take a small sample, test it to breakthrough, and scale the result, but the problem with that is that it won't accurately reflect the geometry effect of your scrubber design. As you indicated, it won't have been consumed evenly. The best thing is probably simply to use it until you detect breakthrough, and then change out the media, or call the dive. If you can't do that though, just dump it and replace it with fresh media. Scrubber media is cheap compared to the potential consequences of an exhausted scrubber. Atmospheric air contains about 400 ppm CO2. If your scrubber is not sealed, it will gradually become depleted simply by exposure to air, and this doesn't require active circulation. Gas exchange will be driven by the concentration gradient, though that is a slow process. There are tests you can do if you want to sample the media and send it out for chromatography analysis, but for a small scrubber, such a test is probably more expensive than a media replacement.

Sean

-------- Original Message --------
On Oct. 10, 2019, 12:29, Brian Cox via Personal_Submersibles wrote:

> Hi All,
>                   Does anyone know if there is some sort of test, like maybe a chemical test , to determine the state of some CO2 absorbent.  Like how full of CO2 it is.  I've ran my scrubber on some of my short test dives but since then the absorbent material has just been sitting in the scrubber .  Obviously the fan has not been running all this time and the only real exposed granuals are around the perimeter of the scrubber.  It would be nice to know just how spent the absorbent material gets just sitting in the atmosphere .
>
> Brian
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