Options for Keeping CELLS DRY

[jale]

Whats about a little tap on the head (and orientating yourself in a way to have help from gravity) to try to remove some moisture...
Done regularly with front units

 

[RainPilot]

Specific design of cell and Orientation of cell in use and Ability for the cell face to trap water all have a factor.
Seems the biggest win is a cell without threading on the front, that has a flat face, orientated at about 45' to the divers orientation no matter if vertical or horizontal, at the top of the loop.

Most means to resolve the cell design issues are covered in https://www.deeplife.co.uk/or_files/DV_O2_cell_study_E4_160415.pdf

You should find how the manufacturer has tested and designed out this specific risk in your rebreathers FMECA

I am sure your PDF will assist the OP in rectifying an issue they have in their existing SM CCR, which may or may not be moisture related.

 

[rjack321]

This past trip I was in a quarry, the temps above 20' were 75 degrees F. below 20' it dropped off, the coldest i was in was around 50, but not long for the 2nd dive. mostly was doing some practice drills around 30-40' so the temps werent that cold. computer shows temps there were around 65 degrees.

usually in FL where I dive the temps are 68. I have the same problem on longer dives in FL also.

I'm guessing something else if going on. Have you put some deoxit on the molex pins? How old are the cells? I have had terrible luck with the AIs in the past compared to the Vandergraphs. I heard the AIs are better now and was forced to buy some due to the supply chain issues but haven't used any new era ones yet.

 

[jason black]

Rebreather cells should not be wet!
I have flown many units and most seem to always have moisture on them.....
thats BS! should not be.....
My current unit the head and cells are DRY always no matter how long the dive.......
molex connectors are Junk, so are fisher...... dump the molex connectors get a solo connector on the computer..... as for cell moisture thats the design of the unit i would look elsewhere.....

 

[rsingler]

My current unit the head and cells are DRY always no matter how long the dive.......

And your current unit is...?

Ah, from another thread, I see Tiburon.

 

[Brad_Horn]

I am sure your PDF will assist the OP in rectifying an issue they have in their existing SM CCR, which may or may not be moisture related.

Not my pdf but if the OPs cells or cell faces in their unit are getting wet as indicated by the threads title, moisture would appear to be involved and they are at high risk of waterblock, with the obvious resultant risk to the OPs life that offers. If anyone doesn't get the significance of this risk refer to the DL link above where it has been highlighted in yellow as a unique risk of using wet galvanic oxygen cells. That is seemingly poorly understood by a number of rebreather divers and historically more than one manufacturer (inclusive NEDU per their EX19 accident investigation).

It doesn't take much water on the cell faces for the PPO2 you're breathing to not equal what you are seeing off your PPO2 display or that any voting logic is working off.

In which case the OP probably needs to take their seemingly still prototype unit back to the drawing board for another round of unmanned testing to identify the root cause of the design issue or issues causing the wet cells. Be it potentially caused by a specific range of water temperature, the specified cell design itself, how the cells are located/retained in the unit, something like a scrubber pressing up to the cell face funneling water onto it or the individual cell location/orientation.

The OP trying to apply or find a solution as a bandaid or checklist tick box is unlikely to rectify something like wet cells where it is an outcome of a units design.
The manufacturers unmanned testing as part of their initial R&D process ought to have identified exactly what the safe envelope to dive the unit in question is. And if the cell faces are getting wet as a matter of course, either the OP is diving outside those safe limits characterized by the units manufacturer or they are diving it in a manner or environment that is potentially untested and which puts their life at risk.

 

[rjack321]

And your current unit is...?

Ah, from another thread, I see Tiburon.

In the first post the OP says its a kiss sidewinder. I have one but dont have moisture problems unless the water is especially cold (<6C) which creates condensation in the inhale loop

 

[rjack321]

@tbone1004
the cells I am using are:
Analytical Industries (AI) PSR-11-39-MD
these have a Hydrophobic membrane

If these cells won't reach 1.6 at 20-25ft at the end of the dive they are old and need to be retired. Reaching 1.6 at the start of a dive and failing later is unusual but a bad sign.

 

[cerich]

Won't reach and hold at 20 on CCR even if perfect cells. Start or end of dive. 25 easy peasy

If these cells won't reach 1.6 at 20-25ft at the end of the dive they are old and need to be retired. Reaching 1.6 at the start of a dive and failing later is unusual but a bad sign.

 

[rjack321]

Won't reach and hold at 20 on CCR even if perfect cells. Start or end of dive. 25 easy peasy

I have to be a little deeper to account for offgassing inerts but they still need to hit 1.6