Safety of radial vs axial scrubber

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MeRodent said:
Paul my point is that this thread started to read like a joke a considerable time ago.

And Gian, I think everyone on this thread understands your desire to dive nothing but numbers in isolation, that only NEDU testing is good enough, CE is a total waste of time (doesn't affect me in Australia anyway) and all CCR deaths are related to WOB.

I received a Dilbert calendar for Christmas and there is a cartoon that I think applies here. Alice (one of the characters) asks "If I can get sworn statements from everyone here that we understand your point, will you stop talking?"
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Don't put words on my mouth which are not mine and which I do not agree with.

"CE" has failed me and is failing the consumer and it cannot be trusted in isolation.

That is why I am resorting to collecting numbers and making decisions on true facts rather than "fairy tales" (to quote RC).
 
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JacobT said:
I'm not tooting any particular team here, but I have to ask. Are all those "upgrades" tested on the unit you are applying it to?

Saying one BOV is better because it has lower WOB is surely only applicable if it has been tested in your specific unit. Again I have to refer to my lack of CCR experience but from what I have read this seems to be a rather complicated area and just because XYZ reduces WOB on unit X doesn't automatically mean it reduces WOB on unit Y?

-Jacob

PS. personally, I find it strange when someone asks for numbers to compare with his/hers without providing ones him/her self (it might have been provided earlier in the thread and I missed it, in which case ignore this comment)
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You can look at items in isolation, and you can look at items in combination.

I prefer to do both.

However, speaking about BOV (or DSV), you cannot compare two BOVs if you do not have WOB numbers for them.

They could be tested in isolation, or they could be tested on the same unit under identical conditions, or both, and then you can talk about the WOB of one vs. the other.

There is more that you can do though, and that is measure the internal volume of one BOV and compare it to the internal volume of the other.

You can also measure the internal diameter of the mushroom valves (or surface area excluding the spider) and compare it to that of the other.

Then you can compare the ratios of the various dimensions of one BOV vs. the other.

...and mushroom valves are important (if they are not the Draeger ones, I need evidence that they are as good or better).

What you cannot do is replace a tested BOV (or DSV) with an untested one, or use a BOV (or rebreather) for which you have no test data (meaning I want all relevant test data, and not the one the designer cherry picks which is good, without disclosing that which is bad).

The same applies to scrubbers and rebreathers overall, but no numbers, and I don't buy it and I don't dive it (personal choice), and where numbers are available, I take those into account.
 
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anarchista said:
I checked the text resists re-conversion and is clear enough for those who know about it.
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sorry, it must be the fact that english is not my native language

can please someone explain to me what rc is trying to tell me

to me it reads like:

gdy tekst czyta***263; my, który odczytuje ka***380;dy conversie ***322;atwe
Sk***322;adnik kanister ubywa, przychodzi inny. Nawet w powa***380;nych przypadkach mo***380;na mówi***263; o bajkach.
 
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Gentlemen. I'm getting reports that this thread is getting a little heated.

Help me by remembering it is the season of goodwill.
 
MeRodent said:
I received a Dilbert calendar for Christmas and there is a cartoon that I think applies here. Alice (one of the characters) asks "If I can get sworn statements from everyone here that we understand your point, will you stop talking?"
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It's entitled "Annoying":

108770.strip.gif


Good find ;-)

Randy Thornton said:
I would also add that the axial vs. radial scrubber argument is a little bit of a red herring. There is much more that goes into the performance of a scrubber than just whether it is radial or axial. Things such as gas flow, size, environmental protection (insulation) and so on and so forth have a huge impact on the overall performance and duration of the scrubber. IMHO, simply stating that radial or axial is a preferred design, is not possible without taking into consideration other design elements which highly impact the performance of the scrubber.
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Fully agree Randy, the system needs to be considered as a whole. Isn't the Boris a Radial scrubber - I certainly wouldn't consider one of those, they are just too complicated and I hear they leak a lot!

JONT said:
I've put 9 hours on my revo in Ginnie on one very long day with standard axials.....BUT you need to consider other factors like the following that swing duration BIG TIME.
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That's a very long dive! I take the same approach to you - you must look at the whole dive and then assess how you're going to do it. Rebreathers make this possible. For me it's about the dive and not so much about the equipment.

Cheers
Matt.
 
paulraymaekers said:
sorry, it must be the fact that english is not my native language

can please someone explain to me what rc is trying to tell me?
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Paul,

RC I think is saying that some of your theory is not entirely correct.

Personally, I think it is irrelevant. No one theory is better than anybody else's until a peer reviewed scientific study has been accepted by the scientific community as "best."

Humbly, it would be more interesting for you to share what you know, like the Hydrostatic Imbalance of the rEVO, and the performance numbers of the rEVO Radial scrubbers, than discuss theories with RC (given the language barrier and the limitation of unsubstantiated theories).

Numbers, not theories, preferably, please.
 
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paulraymaekers said:
sorry, it must be the fact that english is not my native language

can please someone explain to me what rc is trying to tell me

to me it reads like:

gdy tekst czyta***263; my, który odczytuje ka***380;dy conversie ***322;atwe
Sk***322;adnik kanister ubywa, przychodzi inny. Nawet w powa***380;nych przypadkach mo***380;na mówi***263; o bajkach.
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As I read it, and without the odd remarks, there are 2 questions for you:

1) Do you know the chemical equation for binding of CO2 in a scrubber? (#175).

2) Do you know why rear-mounted CL's are inferior? (#183)?

- #2 I've had to guess a bit about the meaning of "objections"

The tone it weird. RC - did you mean to insinuate that Paul does not know what he is talking about? Of the posters in this thread Paul is the only one with any practical test knowledge, so I have a hard time believe this is not a language issue.

Matt.
 
paulraymaekers said:
can please someone explain to me
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Read the discussion to the left link.
Understand solution Lundgren-Arborelius, I given links to the source publication.
You can put bellows breath weight balanced (a solution other than breathing bag) on the back and have a little work of breathing.
That is a fairy tale, you can not do that.
It is used in the DCSC, IS-Mix (AGA) Interspiro (Ocenco).

matt said:
The tone it weird. RC - did you mean to insinuate that Paul does not know what he is talking about? Of the posters in this thread Paul is the only one with any practical test knowledge, so I have a hard time believe this is not a language issue.
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To use the stream continuity equation, we must have a situation in which a physicist. Here, the process is complicated by the chemistry of one of the components taking part in the chemical reaction and disappears.

greet rc
 
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Matt, I was trying to figure out what rc ment with this:

anarchista said:
The canister component wanes, comes another. Even in serious cases you talking about fairy tales.
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I suppose he means 'vanes'

I assume he sais I am telling fairy tales when saying that vanes do not change the dwell time?
 
paulraymaekers said:
Matt, I was trying to figure out what rc ment with this:



I suppose he means 'vanes'

I assume he sais I am telling fairy tales when saying that vanes do not change the dwell time?
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Beats me Paul - you've a better grasp of this English than I have!
 
paulraymaekers said:
Matt, I was trying to figure out what rc ment with this:



I suppose he means 'vanes'

I assume he sais I am telling fairy tales when saying that vanes do not change the dwell time?
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Old December 20th, 2012, 04:39 PM #30 (permalink)
paulraymaekers said:
for the same volume of sorb, there is no difference in dwell time between the flat square and the curved square: shape does not change the dwell time, only volume does (that should be clear: if you double the surface, so half the hight, the speed of gas will be half (double surface), but the path to travel is also half (hight is half), so total travel time (= dwell time) is the same)
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Not valid stream continuity equation for this example. One of the components of the mixture is chemically linked.

greet rc
 
MeRoden said:
I received a Dilbert calendar for Christmas and there is a cartoon that I think applies here. Alice (one of the characters) asks "If I can get sworn statements from everyone here that we understand your point, will you stop talking?"
Click to expand...

Best. Post. Ever!

I laughed so hard i spewed coffee over the ipad.
Have some green.

Im going to store that perfect strip, for future use. Its golden
 
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paulraymaekers said:
euh... and so because of this shape does influence dwell time...?

well,.. enjoy further discussion :-)
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No numbers from you, nothing substantive to discuss, other then for the Meg and the APOC and a few military rebreathers.

How are we to discuss rebreathers without key information?
 
anarchista said:
Give interesting information, that is empty, with no documentation of a particular construction.

greet rc
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The key information like WOB, Hydrostatic Imbalance, and Elastance has been published by NEDU and included in the WOB Comparative Rebreather Database.

Interspiro has chosen to date NOT to release the information.

At some point, maybe, NEDU will, but it does not appear, based on publicly available information, that NEDU is looking that seriously at DCSC, IS-Mix (AGA) Interspiro (Ocenco) - nor that the manufacturers have an interest in releasing key information (by all means they do not have to, if they do not want to).

Regretfully, until we have the numbers, theories are very nice "fairy tales."
 
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gianaameri said:
Regretfully, until we have the numbers, theories are very nice "fairy tales."
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You can measure yourself if you are a scientist or inventor. If only an accountant from collecting digits in columns that understanding will be a fairy tale.
As I needed more information about the behavior of soda lime to restart a partially consumed deposits researched this problem. There were also tests of ice-cold absorber.

greet rc
 
anarchista said:
You can measure yourself if you are a scientist or inventor. If only an accountant from collecting digits in columns that understanding will be a fairy tale.
As I needed more information about the behavior of soda lime to restart a partially consumed deposits researched this problem. There were also tests of ice-cold absorber.

greet rc
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I am "Risk Manager."

Risk Manager uses other people's data to manage risk.

No data = Fairy Tale

False data = Fairy Tale

I am not Rebreather Manufacturer, Rebreather Designer, or Scientist Inventor.

I am not stupid either because I chose the Meg well before NEDU chose the Meg.

I do run my own tests though as well because I can.

You theories are "fairy tale" and your rebreather is "fairy tale" because you do not show Patent and do not show numbers.

Do not take it as an offence, just fact.
 
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