O2 cells falling apart - bad batch?

Drmike

Is it just me?

Thats the 2nd Teleydyne R17 cell thats fallen in half. The whole assembly coming apart from the faceplate (the bit that screws into the holder)

Bad batch?

Both cells C6

anyone else seen this - be nice to get a new cell under warranty

__________________
Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you

AD_ward9

We are aware of a mechanical change in November 2006 to improve robustness and reduce risk of KOH leaking.
Your date is C6, so you need later cells.

Alex

dave t

I have seen four different rebreathers now with failing/faulty c6 cells but the ones I have seen are r22BUD

PacketSniffer

Have you read Alex's (Deep Life) 6 year study on O2 sensors? It's enlightening.

O2 Sensor Research

I had a sensor (R22D) "go out" on me recently. The sensor was born August '06 (H6), ISC placed a date when they removed it from the sealed bag on "11-06". I received it and started using it last week of January '07. I had about 30 dives (~30 hours) on it before it started declining in mV and getting blocked out by APECS 2 (fairly quick failure). I had a spare with me.

__________________


Far better it is to dare mighty things, to win glorious triumphs, even though checked by failure, than to take rank with those poor spirits who neither enjoy much nor suffer much, because they live in the gray twilight that knows not victory or defeat.

AD_ward9

[quote=PacketSniffer;105851]I had a sensor (R22D) "go out" on me recently. If removed from the bag, the cell should be considered operational. The bag is a lot more important than it may appear. If removed from a bag and resealed it can increase the failure rate: the gas in the bag should not be dry nitrogen.

Teledyne sensors failed many of the tests in the report with a lot of quality control issues. We had things like sensors that should be 8s response time being 50s, leaking issues, early failures, etc. IMHO, there is a considerable amount of work to be done by Teledyne to produce sensors suitable for rebreathers. The highest levels at Teledyne do seem committed to put in that work, and we will report the results when they succeed. We cut the Teledyne results from the report, otherwise it reads as too much of an inditement on their products. Having at least two sources is good for everyone, so Teledyne should be allowed to do this without focusing on the past.

Until they have a suitable product, the low risk approach is to use the AI equivalent (in this case, PSR-11-39-MD). The AI cells were the only ones we found suitable for rebreather applications. Alas.

Alex

babar

Alex

Any comment on the K1D's? Are the Teledyne models suitable, if not is there a suitable replacment?

[quote=AD_ward9;105856]

__________________
Babar
Evolution Plus
Sport kiss

schford

Is it a good idea to be using cells that are not approved by the manufacturer?

Warranty and liability issues would worry me.

__________________
Bailout and Kit Management account for Murphy's Law

The only bad question is one you did not ask and later wish you had.

Use of Rebreather World is subject to the Rebreather World Terms & Conditions of Use

PacketSniffer

Alex,

Regarding the resealing of sensors, I've come to understand that statement from a couple of other experienced Rebreather divers. Do you have any material information that can be thrown in the public domain that illustrates that the statement is accurate?

Can you clarify the second part of your statement? Is the bag being filled with dry nitrogen associated with the failure or were you just noting that you shouldn't fill the bag with nitrogen? And if not nitrogen, what do you fill it with?

__________________


Far better it is to dare mighty things, to win glorious triumphs, even though checked by failure, than to take rank with those poor spirits who neither enjoy much nor suffer much, because they live in the gray twilight that knows not victory or defeat.

AD_ward9

I have had long discussions with manufacturers on the bag, with them explaining to me the importance of this apparently simple feature. Sounds silly, but little details all add up to make a product.

The plastic the bag is made from is not just any old polythene that it appears. Then on the gas fill inside the bag, it is nitrogen, but humidity has to be at the right level. The effect changes to this has on storage life is quite dramatic. Basically, rebreather manufacturers should not mess with the bag: they should arrange with the manufacturer to get the correct product in the first place - properly specified, properly tested.

Alex

AD_ward9

This is not one we have tested. Sorry.

Actually, rebreather manufacters cannot supply the cells in Europe with the rebreather: the cells are exempt from the RoHS Directive because they are a medical dual use product, but rebreathers are not exempt.

As regards what is suitable or not, if it is a replacement item, the user can source anything that is a guaranteed replacement. AI state the part numbers quoted are plug replacement parts, so if it fails in that plug replacement role, the redress against AI would be the same as the redress against Teledyne.

It would be helpful if the manufacturers of diving equipment published their component acceptance reports, and if not, then should not be surprised if users vote with their feet on the consumable items that appear to be unsuitable in service. In making our report available, we have no problems if other manufacturers adopt it as part of their safety case: we stand by the accuracy of our measurements and our procedures. All of our results were taken as accurate by the respective manufacturers.

Alex