[PSUBS-MAILIST] CO2 absorbent test

[Sean T. Stevenson via Personal_Submersibles]

Be aware that many of the indicating absorbents depend on moisture content for the colour indication, so they work as intended while actively scrubbing, but if you then expose the spent media to dry air and allow it to dry out, the colour can fade. As such, I wouldn't consider colour a conclusive indication of % media consumption, or at least, only as a best-case-scenario indicator. Consider too that all you see is the layer of media against the glass / acrylic / polycarbonate housing. In axial scrubbers, the consumption front advances as more of a cone unless you have really effective diffusion at the inlet and outlet ports. In radial scrubbers, it will either indicate pessimisticly or optimistically depending on the radial flow direction (outside to inside flow will be most efficient). In any case, scrubber duration is probably best estimated by elapsed time under load compared to a practical test result, and of course a sensor to detect breakthrough when it occurs.

Sean

-------- Original Message --------
On Oct. 10, 2019, 18:39, Brian Hughes via Personal_Submersibles wrote:

> I designed my personal scrubber to use the disposable canisters that fit anesthesia machines. They're clear so I can observe the color change. An anesthesiologist friend helped me in the design. Some of the inspiration came from a Biopak 45 I had modified for diving as a rebreather. I have a larger one for when carrying a passenger.
>
> Brian
>
> Get [Outlook for Android](https://aka.ms/ghei36)
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