Sorb-how much bouncing around in car is bad for packed scrubbers?

[broncobowsher]

I suspect a lot will have to do with how well packed the scrubber was to start with. When I was taught to pack my rEvo they are solid. You shake them and make sure there isn't any rattling inside.

Next would be the ride itself. Sitting on the passenger seat is a nice smooth ride. That is where a car is engineered to be smooth at. Now the bed of a pickup, that is bolted solid to the chassis. No rubber cushions (body mounts). That isn't engineered to be smooth. Tons of vibrations will pass through. Is your drive down a billiards table smooth road, or a washboard dirt road?

I remember when I first got the rebreather (it may still have been during the training class) someone showed up to the boat with a rebreather and decided to check the sorb in the parking lot. It had settled in the drive over and they topped it in the parking lot. I don't remember the brand, just they used a golf ball to plug the inner port during the top off.

 

[arew+4]

No actual re-breather experience, but tons with particle size, particle size distribution, ion exchange resin, and other filter media beds. That said is there a spec for particle size on sorb? How about other distribution factors stdev, span, d50, etc.

If you have a broad distribution and/or a friable particle, you could experience segregation and packing cause by vibration over time. You would end up with large spaces between large particles on the high side and tightly packed mixed particles on the low side. This would effectivity reduce the working surface area of the sorb. It may seem to be tightly packed, no rattling etc. but could be far less effective

 

[Raphus]

Interesting.. I just wondered about this..

When I use a new scrubber, I try to fill it at the dive destination.
If it's a used scrubber, I open the rebreather at the dive site and shake it, listen to rattling particles.
Never had an issue yet, but I imagine it can happen..

I dive a SF2. The scrubber is packed with a spring, so even if it sattels the spring is recompressing. Channeling is less likely, but can still occur ofc..

 

[telemonster]

Im pretty sure if you take a packed tight scrubber and vibrate it a bunch the sorb granules will indeed settle even more. I have noticed packed tight scrubber that I started with seemed to have a little room after tearing unit down for cleaning. That was after driving 3.5 hours to site on paved roads, diving, then driving back and unloading equipment. Unit is a prism2 which doesn’t have a spring in the canister itself. It left me more apt to fill on site.

 

[justinthedeeps]

Good chance it settles more. Didn't have issues with a few rowdy 4x4 roads yet We overpack the JJ canisters by ~200+ grams because it can easily settle 2-3+ cms. Breathing resistance seems unaffected (not actually measured though)