Detail from Inspiration CCR

Credit:   AP Diving

The Temp-stick in the Vision equipped rebreathers is optimised for use ONLY with Sofnolime 797. If you use other grades or makes of Sodalime, the scrubber display may show you the temperature activity through the bed but the 1st and 2nd scrubber warnings will occur too late.

If you want to use another grade or brand of Sodalime, you cannot rely on the Temp-stick warnings and you need to know from the supplier:

the duration that material gives you in your specific rebreather, at depth, in appropriate temperature conditions, at a reasonably hard work rate. ( We test at 40 RMV and 4C and at 75 RMV and 4C).

If the supplier cannot give you sufficent information then you are effectively a "test diver".

Why does the granule size matter?
The smaller the granule, the larger the surface area of sodalime in contact with the incoming gas, so the CO2 is absorbed within a shorter bed length; i.e. the "reaction zone" is shorter with small granule materials.

CO2 comes through the scrubber when the front edge of the reaction zone reaches the far end of the scrubber.

The larger the granule size, the longer the reaction zone, the earlier CO2 comes through.

Depth has an incredibly detrimental effect on scrubber duration and we have seen in our test rig extremely short durations with coarse granule absorbents.

Sodalime manufacturers don't have the equipment, generally, to test their products at increased pressures. Please ask appropriate questions before using other grades.

All APD scrubber durations are based on Sofnolime 797.

If you have any questions please advise.

If you want to cross post to other forums, PLEASE COPY the entire text, not part text.
Confidentiality notice removed intentionally.

kind regards

Martin Parker
Managing Director
Ambient Pressure Diving Ltd
MartinParker@apdiving.com
www.apdiving.com
Tel: +44 (0)1326 563834
Fax: +44 (0)1326 565945