Reusing a scrubber?

[happy-diver]

https://web.archive.org/web/20080518082010/http://www.nobubblediving.com/frankenson.htm

Now, by popular demand, here's a reprint of my famous

LEGAL ADVICE FOR THE STUPID

"The next time you go to the market, remember that half of the people that you meet are of below average intelligence".

WARNING! Rebreather Diving is a dangerous sport. It weeds out the weak by KILLING them. Can I make it any clearer than that? SO: Remember, Rebreather-Diving AT ALL is dangerous enough. Making up EXPERIMENTAL rigs from parts gathered from here and there is about as iffy as it gets. DON'T try this if you don't know what you are doing. If you get killed following my methods, then shame on you! Don't let your family come crying to me as to how I facilitated YOUR death. The bottom line is that if you could not do this sort of conversion WITHOUT READING ANY INSTRUCTIONS AT ALL you are not ready to do it by following my methods. Hey! Be careful out there, huh? If you want to persist in twisting the tail of the Dragon, Go read my Philosophy Page now to see if you have you head screwed on in the right way to accept these risks.

 

[lermontov]

https://web.archive.org/web/20080518082010/http://www.nobubblediving.com/frankenson.htm

Now, by popular demand, here's a reprint of my famous

LEGAL ADVICE FOR THE STUPID

"The next time you go to the market, remember that half of the people that you meet are of below average intelligence".

WARNING! Rebreather Diving is a dangerous sport. It weeds out the weak by KILLING them. Can I make it any clearer than that? SO: Remember, Rebreather-Diving AT ALL is dangerous enough. Making up EXPERIMENTAL rigs from parts gathered from here and there is about as iffy as it gets. DON'T try this if you don't know what you are doing. If you get killed following my methods, then shame on you! Don't let your family come crying to me as to how I facilitated YOUR death. The bottom line is that if you could not do this sort of conversion WITHOUT READING ANY INSTRUCTIONS AT ALL you are not ready to do it by following my methods. Hey! Be careful out there, huh? If you want to persist in twisting the tail of the Dragon, Go read my Philosophy Page now to see if you have you head screwed on in the right way to accept these risks.

I like the philosophy page

 

[rjack321]

There is a good representation of the reaction front in a scrubber canister here:

A Look Inside Rebreather Scrubber Canisters, Part 1

and

A Look Inside Rebreather Scrubber Canisters, Part 2

If you watch the videos you can get a feel for how having mixed up old and new sorb granules could lead to problems.

The author is the former director of the Navy Experimental Diving Unit (NEDU) & his blog should be required reading for every CCR diver.

 

[Gareth J]

I am some what surprised and concerned that it appears that the practice of reusing scrubber material is still happening. By that I mean repacking a scrubber with previously used material.

When I first started diving a CCR over 15 years ago, we where told NEVER reuse scrubber material. I started during the wild west period, or just towards the end of it. We were still learning, and there was a high attrition rate in the CCR community. I thought these hard won lessons had been learnt.

We should have learnt by now,
Change your sensors regularly (on time), or as soon as they start to play up.
Don't repack scrubbers
Don't over dive your scrubber.
Prebreath the unit.
Be diligent in assembly and test prior to diving.
Pay attention to your PO2 (something I still struggle with).

CCR diving is not cheap. But don't skimp on sensors and lime, they are the cheapest part of diving.

 

[Jeremy Williams]

I am some what surprised and concerned that it appears that the practice of reusing scrubber material is still happening. By that I mean repacking a scrubber with previously used material.

When I first started diving a CCR over 15 years ago, we where told ...

These things happen. Old lessons are forgotten and rediscovered. Improvements to scrubber design and ever more suitable material (i.e. Sofnolime 797) make the entire process more and more tolerant of error even in the face of practices that might have been quickly fatal 20 years ago. And for the record, I agree that re-packing a scrubber with partially used absorbent is not a good plan.

As a tangent, I was reminded of an article I read years ago about scurvy... If you don't mind a long read, you may enjoy it. The British had (and lost) the cure for scurvy multiple times. Advances in technology allowed them to unwittingly replace the effective cure with an ineffective one. A good practice was replaced with a poor practice without immediate harm. It wasn't until pressed that the ineffective cure fell flat and caused the death of so many. For the simple lack of common ascorbic acid...

Scott And Scurvy (Idle Words)

 

[jale]

These things happen. Old lessons are forgotten and rediscovered. Improvements to scrubber design and ever more suitable material (i.e. Sofnolime 797) make the entire process more and more tolerant of error even in the face of practices that might have been quickly fatal 20 years ago. And for the record, I agree that re-packing a scrubber with partially used absorbent is not a good plan.

As a tangent, I was reminded of an article I read years ago about scurvy... If you don't mind a long read, you may enjoy it. The British had (and lost) the cure for scurvy multiple times. Advances in technology allowed them to unwittingly replace the effective cure with an ineffective one. A good practice was replaced with a poor practice without immediate harm. It wasn't until pressed that the ineffective cure fell flat and caused the death of so many. For the simple lack of common ascorbic acid...
Scott And Scurvy (Idle Words)

Really good and instructive reading. Thanks.
I just hope this confusion "reuse canister-reuse lime" won't become a "lemon-lime" confusion as explained in this story.
This small word "lime" gives troubles whatever its meaning

 

[Jeremy Williams]

This small word "lime" gives troubles whatever its meaning

You see how it stirred my memory!

 

[Reku]

Read my posts immediately above. That's not what -- if I read his post right - he is doing. I have no problem doing multiple dives on a single canister so long as it is not repacked between dives.

Unless I misread his post - and I apologize if I did - what he's doing is emptying the scrubber out, putting the loose media in a ziplock bag, and then repacking the can later with partially used sorb that has been all mixed up. That's bad practice and is totally different than what we've been discussing and is the subject of the link you attached, which about storing the whole canister.

Oh ..... If He's emptying the scrubber into a bag and repacking...that's extremely dangerous...

I may of misread the post. It never crossed my mind that someone would empty and store partially used material and then repack that material at a later date. Sorry if I was mistaken. I never expected that. Maybe my brain skipped over it? That's horrifying. That messes the entire dynamic of the scrubber heat front that moves through the scrubber basket.

Not good.

 

[broncobowsher]

It doesn't look like the original poster who said they were pouring out the sorb and pouring it back in later. It looks to be a later poster that said that is what they were doing. So give credit to the OP is they may have saved another's butt with this thread.

 

[stuartv]

I just wish y’all would tighten up a bit on your terminology.

I think some people have posted about “reusing scrubber” when they really meant reusing sorb. To me, scrubber is a hard part of my ccr that gets packed full of sorb.

Imprecise terminology can be really confusing to newbs (like me) who are just here to read and learn.