Safety of radial vs axial scrubber

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paulraymaekers said:
well, people seem to forget that a radial is nothing more then a very wide, square shaped, limited hight axial that is bent in a curve so it becomes a tube

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)

now everybody understands that if you compare 2 axials with the same total volume, but one less wide and higher, and the other one very wide, but not high, the first will have a bit higher WOB, the second will have a bit higher risk of preferential break-trough

there is no data that shows that, for the same volume of sorb, the duration of a radial is longer then the duration of an axial (I would even think the inverse, but no statistical data available either)

so all this fuss about what is better... it is not black and white
Click to expand...

Posted a graph of Molecular material behaves like a dynamic binding capacity of CO2.

http://rebreathers.pl/forum/download.php?id=39

The binding capacity of the lower speed is a little higher is not a linear function.
Your argument has no basis for the same lime soda, a fine, or even more fat.

The long axis absorber is a good thick soda lime, because it has less breathing resistance, but less ability to bind CO2.
The short length of the absorber is convenient small soda lime has a higher breathing resistance and a greater ability to bind CO2.
see also this passage Molecular materials.

http://rebreathers.pl/forum/download.php?id=40

This your argument is also has no basis in the light of known knowledge.

greet rc
 
gianaameri said:
There is an interesting document here:

http://www.jj-ccr.com/media/4950/test_report.pdf

I am not sure if the test result numbers are for the radial or axial scrubber. Some are for the back-mounted counterlung and other numbers are for the front-mounted ones.

Reports/numbers can be confusing at times.
Click to expand...

That one is for the Axial.

For the radial, go here: www.jj-ccr.com/media/4972/radial_test_report.pdf

The new JJ website hides it below a scroll at: DOWNLOADS - JJ-CCR
 
anarchista said:
Posted a graph of Molecular material behaves like a dynamic binding capacity of CO2.

http://rebreathers.pl/forum/download.php?id=39

The binding capacity of the lower speed is a little higher is not a linear function.
Your argument has no basis for the same lime soda, a fine, or even more fat.

The long axis absorber is a good thick soda lime, because it has less breathing resistance, but less ability to bind CO2.
The short length of the absorber is convenient small soda lime has a higher breathing resistance and a greater ability to bind CO2.
see also this passage Molecular materials.

http://rebreathers.pl/forum/download.php?id=40

This your argument is also has no basis in the light of known knowledge.

greet rc
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Are you talking about the size of the scrubber, or the size of the individual sorb bits. We know that sofnolime for example are (in 797) smaller, work better and have higher WOD, than say the CD, which is bigger, has better WOB and does not work as well. that's not the discussion is it?

Or, are you comparing fine grade sorb in a radial scubber with coarse grade sorb in an axial scrubber/
 
anarchista said:
This your argument is also has no basis in the light of known knowledge.

greet rc
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?? I think something got lost in the language

what do you want to say?

I just pointed out that the dwell time, so the time the gas is in contact with the sorb, is not influenced by the SHAPE of the scrubber, but only with the VOLUME, when all other parameters are kept the same
 
paulraymaekers said:
?? I think something got lost in the language

what do you want to say?

I just pointed out that the dwell time, so the time the gas is in contact with the sorb, is not influenced by the SHAPE of the scrubber, but only with the VOLUME, when all other parameters are kept the same
Click to expand...

The canister does not work all the time in the all entire volume.
Main binding of CO2 occurs in the Reaction Zone.
The flow rate through the zone of influence on the ability to bind CO2.
(The graph of Molecular Materials.)

"How an absorber works"
http://www.molecularproducts.com/pd...troduction to Sofnolime Technical Article.pdf

I recall ( #13 (permalink)) another material confirming dependence of the reaction zone of flow rate.

http://rebreathers.pl/forum/download.php?id=41

Why Paul, Auer (MSA) have used decades radial sinks to escape equipment?

http://rebreathers.pl/forum/download.php?id=66

greet rc
 
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The canister does not work all the time in the all entire volume.

that is clear


Main binding of CO2 occurs in the Reaction Zone.


yes, clear

The flow rate through the zone of influence on the ability to bind CO2.
(The graph of Molecular Materials.)

ok, but the graph is not important


"How an absorber works"
http://www.molecularproducts.com/pd...troduction to Sofnolime Technical Article.pdf


yes yes, but please distinguish between papers for general public reading, and scientific documents


I recall ( #13 (permalink)) another material confirming dependence of the reaction zone of flow rate.

http://rebreathers.pl/forum/download.php?id=41



ok, but that has no relevance here



Why Paul, Auer (MSA) have used decades radial sinks to escape equipment?
http://rebreathers.pl/forum/download.php?id=66


also that does not have relevance here: do the test and see what happens!



you seem to forget that the reaction zone is something dynamic, that changes all the time, even with every breath: if some CO2 is not grabbed in a specific area, it will be captured in the next area, so the reaction zone has shifted a bit

the reaction zone is not the catalist for the CO2 absorbtion, it is the result of it


theory is only valid until practical tests show the opposite
 
divingtactics said:
That one is for the Axial.

For the radial, go here: www.jj-ccr.com/media/4972/radial_test_report.pdf

The new JJ website hides it below a scroll at: DOWNLOADS - JJ-CCR
Click to expand...

Useful information, I will add it to the WOB Comparative Database.

In the case of the JJ, the numbers show that the Radial is NOT safer in terms of WOB, but it is safer to the extent that Duration is longer.

First case ever I see of a Radial not offering WOB advantage over the Axial in the same rebreather.

The numbers suggest the JJ Radial is not worth paying extra money if you are seeking a reduction in WOB (while the rEVO and ISC 8 lbs Radials do offer a significant reduction of WOB).

I am surprised and I would run the tests again for both the Axial and the Radial to confirm the numbers are correct, unusual results.

The test results are incomplete though (no numbers for the Radial at 100 meters).

Do you know if and where they can be sourced?

Hydrostatic Imbalance numbers would be useful/essential to know as well.
 
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paulraymaekers said:
rc: do a real test and show the result!

theory is only good when proved by practical testing/experience
Click to expand...

You showed some material in support of his thesis?
Molecular show that you are wrong.

I reported in Faser inventive design, was adopted.
Access to scientists working for Faser I, those who are employees of the Naval Academy. Dr. Danuta Grzywaczewska dead unfortunately, was involved in the development of Polish Ostaryt soda lime. Access to the author of "Soda Lime in Military Applications," Professor Commander Ryszard Klos, I do.

greet rc
 
paulraymaekers said:
rc: do a real test and show the result!

theory is only good when proved by practical testing/experience
Click to expand...

I do love the way that an argument has formed with the only person on this board that has the known technology in their personal possession to disprove any theory contrary to his point of view and would have had to run the tests as part of the CE efforts, big balls RC.

I would suggest Paul however that it would not be worth bothering, your point is logical and requires no further validation.
 
Peter L said:
I do love the way that an argument has formed with the only person on this board that has the known technology in their personal possession to disprove any theory contrary to his point of view and would have had to run the tests as part of the CE efforts, big balls RC.

I would suggest Paul however that it would not be worth bothering, your point is logical and requires no further validation.
Click to expand...

There is no logic other than in actual numbers when it comes to scrubbers and CO2 absorption in a rebreather.

There are so many variables to consider that the truth is only in a significant number of test runs yielding consistent results.

Of course there are "Opinion Leaders" and those who need to follow the leader either as a basic human need or for profit, but only numbers can validate theories (no matter who is the originator of the theories).

Bottom line, it would help if more manufacturers would post test results from independent test houses or to the very minimum put the actual figures (complete to include a. WOB, b. Hydrostatic Imbalance, c. Elastance, d. Duration, e. Test parameters...) in the CE manual which we know is audited by a Notified Body (for what this may be worth).

To be specific, for the rEVO Radial performance, for example, we only have hearsay numbers shown at a Trade Show (I am not aware of other sources). It would be nice to have actual test reports from the test house like JJ has done, so that we can talk reality, rather than theory.
 
paulraymaekers said:
?? where?

it is my impression you draw conclusions to fast. You must check your conclusions.
Click to expand...
You will present a "stream continuity equation", true.
Pull out of the proposal for the behavior of soda lime, this is not true, where the binding efficiency of CO2 depends on the speed of the reaction zone.

rc greet
 
Peter L said:
I do love the way that an argument has formed with the only person on this board that has the known technology in their personal possession to disprove any theory contrary to his point of view and would have had to run the tests as part of the CE efforts, big balls RC.
Click to expand...

Peter L said:
And you sir are a shyster and a fraud, the deepest parts of hell are reserved for your brethren and I hope you get to meet them someday soon.
Click to expand...

no comment

greet rc
 
anarchista said:
no comment

greet rc
Click to expand...

RC, frankly build a bridge, your insults are just as well formulated.

And for the public record my comment was a response to your "You are primitive, do not know the subject matter"

Net net patent trolls don't produce products and your one while all you have are patents and in this case Paul has products and proof of testing to say your wrong. As I said, big balls....
 
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Peter L said:
Paul has products and proof of testing to say your wrong.
Click to expand...

Not true.

We have seen no proof of testing from rEVO as of yet nor proof of testing from RC (although they may exist in both cases).

JJ has shown some proof of testing.

ISC has shown some proof of testing.

NEDU has shown lots of proof of testing and research.

The above is not to be read as a positive or negative statement for or against anybody or any product, but just as a statement of fact.
 
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gianaameri said:
The above is not to be read as a positive or negative statement for or against anybody or any product, but just as a statement of fact.
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Gian, no argument with you and apologies you took my other comments the wrong way, it was not aimed at you in the way you presumed.

On this topic and most of yours, the English saying is you catch more bees with honey than vinegar, no need to labour the point quite so much, we get it already.

P
 
Peter L said:
Gian, no argument with you and apologies you took my other comments the wrong way, it was not aimed at you in the way you presumed.

On this topic and most of yours, the English saying is you catch more bees with honey than vinegar, no need to labour the point quite so much, we get it already.

P
Click to expand...

I read your comment right, no apologies required.

I just think your comment is wrong (the way it is written).

To use your metaphor, we have a case of busy bees pimping their Patent/Product/Ideas for money and not for honey, but neither shows the beef.

The Italians would say "E' il bue che dice cornuto all'asino" ("The pot calling the kettle black" for the English).

All I am saying, we need numbers on rebreather scrubbers performance, not "theories."
 
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GO.. said:
After thinking for a long time, I have decided that I should go over to dive ccr.
I am very cautious by nature, and now it just before I'm about to order a unit.

I wonder:
I currently live in northern Norway, and the water temperature is usual between 4 and 12 degrees Celsius.

Is axial scrubber safer than radial scrubber?

- Gerhard
Click to expand...

This thread is quite interesting when all the noise is filtered away but I doubt it has helped you any in deciding on your scrubber type beyond Paul's first post.

4-12C is a bit colder than UK, but not much. You'll likely not be diving in 4C for long. 4C is the temperature that CE test for endurance is performed.

On this basis I would not select a unit based on scrubber type. The most popular units have axial scrubbers and they work just fine for your purpose.

I'd look at availability, service and parts availability and a good look at what your buddies are using and take it from there.

Matt.
 
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