Rebreather Comparison Chart

silent running · 18th October 2007, 03:53

Quote: (Originally Posted by iain-hsm)

In most studies they have been on the effect of gaseous bends caused by the diluent gas, nitrogen N2 etc however the latest studies on mice have shown that high C02 breathing causes a local supersaturation of C02 in the lower gut and spleen. When the mice are then subjected to intravenous nitrogen gas (bends) the N2 bubbles formed increase in size faster and larger dependant on the amount of C02 in super saturation that had occurred earlier in the spleen, prior to the onset of the bends. The resultant gas bubble production also has been observed to cause liver damage. Your advantage with Prism is the low WOB and good scrubber exchange. Iain Middlebrook

Always nice to have an advantage Iain, and if my understanding of history is correct, I have you and Peter to thank for it.

And thanks for the very interesting info on the bad interplay between super saturated CO2 and inert gas loading, I had no idea there was such a phenomenon. I guess the intricate workings of our physiology guarantee none of our vital functions happens in isolation. It is frightening sometimes to think how little we know about constant PO2 diving... -Andy

**fireman** · 19th October 2007, 01:45

So the YBOD is the only CE approved breather and it has killed more divers than any other--so much for that standard. rEvo combat swimmer and loving it. My rEvo does breath better than my aka-60. My PeePee is longer than yours also...
I think if you correct for man breast mass, the numbers will make much more sense.

Abbo · 19th October 2007, 11:27

Am I reading this right? I looked for WOB numbers for OC regs and came up with this:
Divernet | Group tests | 15 Regulators on test
50m depth with 63 l/min ANSTI test.
The best reg was the Atomic Z2 at 0.72J/l. Most of the regs were below 2J/l
Against this, only the Boris has a WOB below 2J/l.
I suppose it makes sense since you're breathing through 2.5kg of kitty litter. Makes it pretty clear that you should be far more liberal with the helium than you would be with OC.

paulraymaekers · 19th October 2007, 11:34

Quote: (Originally Posted by Abbo)

Am I reading this right? I looked for WOB numbers for OC regs and came up with this:
Divernet | Group tests | 15 Regulators on test
50m depth with 63 l/min ANSTI test.
The best reg was the Atomic Z2 at 0.72J/l. Most of the regs were below 2J/l
Against this, only the Boris has a WOB below 2J/l.
I suppose it makes sense since you're breathing through 2.5kg of kitty litter. Makes it pretty clear that you should be far more liberal with the helium that you would be with OC.

difficult to compare: in OC you exhale directly into the water :-)

paul

Abbo · 19th October 2007, 12:29

Quote: (Originally Posted by paulraymaekers)

difficult to compare: in OC you exhale directly into the water :-)

paul

I don't follow: a joule's a joule isn't it?!

paulraymaekers · 19th October 2007, 12:44

Quote: (Originally Posted by Abbo)

I don't follow: a joule's a joule isn't it?!

I mean, in general, it is far easier to devellop OC with less then 1J/l than CC, because in OC, you exhale directly in the water, and not in a restrictive system

paul

iain-hsm · 19th October 2007, 13:09

Quote: (Originally Posted by AD_ward9)

EN14143 is on the internet.

the Russian definition of an expert: A person who has made all possible mistakes in a very narrow field. I am getting there slowly

Alex

My father I recall had a similar saying, as consultant engineers concentrating on each smallest component in an overall design. As we got to understand more and more about less and less of the design, more and more time was taken up on less and less important parts of the project.

“Keep this up and we will know everything there is to know about bugger all”

iain-hsm · 19th October 2007, 15:24

Quote: (Originally Posted by PhilSiswick)

This is fascinating - many thanks. What conclusions do you draw for recreational (say up to 50m diving)? A shallower change to rich mix to reduce the amount of N2 in the gas? Or do you think that the same mechanism applies to He bubbles?

Cheers,

Hi Phil

Not to go off post, but you cant make this conclusion as it is C02 retension that is the precurser re mix I will post (new post) some of the early work in the C02 retainers later.

18th October 2007, 03:53	#101 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,777	Re: Rebreather Comparison Chart Quote: (Originally Posted by iain-hsm) In most studies they have been on the effect of gaseous bends caused by the diluent gas, nitrogen N2 etc however the latest studies on mice have shown that high C02 breathing causes a local supersaturation of C02 in the lower gut and spleen. When the mice are then subjected to intravenous nitrogen gas (bends) the N2 bubbles formed increase in size faster and larger dependant on the amount of C02 in super saturation that had occurred earlier in the spleen, prior to the onset of the bends. The resultant gas bubble production also has been observed to cause liver damage. Your advantage with Prism is the low WOB and good scrubber exchange. Iain Middlebrook Always nice to have an advantage Iain, and if my understanding of history is correct, I have you and Peter to thank for it. And thanks for the very interesting info on the bad interplay between super saturated CO2 and inert gas loading, I had no idea there was such a phenomenon. I guess the intricate workings of our physiology guarantee none of our vital functions happens in isolation. It is frightening sometimes to think how little we know about constant PO2 diving... -Andy
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19th October 2007, 01:45	#102 (permalink)
fireman rEvo combat swimmer Current Rebreather/s: rEvo Other CCR Other Rebreather/s: rEvo Other CCR Join Date: Nov 2006 Location: chicago Posts: 442	Re: Rebreather Comparison Chart So the YBOD is the only CE approved breather and it has killed more divers than any other--so much for that standard. rEvo combat swimmer and loving it. My rEvo does breath better than my aka-60. My PeePee is longer than yours also... I think if you correct for man breast mass, the numbers will make much more sense. __________________ Heres to you Capt. Bill Never Forget, and stay safe everyone.
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19th October 2007, 11:27	#103 (permalink)
Abbo Going down on Meg Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Tokyo Posts: 389	Re: Rebreather Comparison Chart Am I reading this right? I looked for WOB numbers for OC regs and came up with this: Divernet \| Group tests \| 15 Regulators on test 50m depth with 63 l/min ANSTI test. The best reg was the Atomic Z2 at 0.72J/l. Most of the regs were below 2J/l Against this, only the Boris has a WOB below 2J/l. I suppose it makes sense since you're breathing through 2.5kg of kitty litter. Makes it pretty clear that you should be far more liberal with the helium than you would be with OC. Last edited by Abbo : 19th October 2007 at 12:10.
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19th October 2007, 11:34	#104 (permalink)
paulraymaekers rEvo's daddy Current Rebreather/s: rEvo Other CCR Home Build Other Rebreather/s: rEvo Other CCR Home Build Join Date: May 2005 Location: belgium Posts: 1,381	Re: Rebreather Comparison Chart Quote: (Originally Posted by Abbo) Am I reading this right? I looked for WOB numbers for OC regs and came up with this: Divernet \| Group tests \| 15 Regulators on test 50m depth with 63 l/min ANSTI test. The best reg was the Atomic Z2 at 0.72J/l. Most of the regs were below 2J/l Against this, only the Boris has a WOB below 2J/l. I suppose it makes sense since you're breathing through 2.5kg of kitty litter. Makes it pretty clear that you should be far more liberal with the helium that you would be with OC. difficult to compare: in OC you exhale directly into the water :-) paul __________________ www.rEvo-rebreathers.com .... the earth is flat, Elvis is alive, and radial scrubbers give longer dwell time than axials...
(Online)

19th October 2007, 12:29	#105 (permalink)
Abbo Going down on Meg Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Tokyo Posts: 389	Re: Rebreather Comparison Chart Quote: (Originally Posted by paulraymaekers) difficult to compare: in OC you exhale directly into the water :-) paul I don't follow: a joule's a joule isn't it?!
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19th October 2007, 12:44	#106 (permalink)
paulraymaekers rEvo's daddy Current Rebreather/s: rEvo Other CCR Home Build Other Rebreather/s: rEvo Other CCR Home Build Join Date: May 2005 Location: belgium Posts: 1,381	Re: Rebreather Comparison Chart Quote: (Originally Posted by Abbo) I don't follow: a joule's a joule isn't it?! I mean, in general, it is far easier to devellop OC with less then 1J/l than CC, because in OC, you exhale directly in the water, and not in a restrictive system paul __________________ www.rEvo-rebreathers.com .... the earth is flat, Elvis is alive, and radial scrubbers give longer dwell time than axials...
(Online)

19th October 2007, 13:09	#107 (permalink)
iain-hsm Custom Title Allowed! Current Rebreather/s: MK 15.X Other CCR Other SCR Other Rebreather/s: Other CCR Other SCR Join Date: Mar 2005 Location: Loughborough England uk Posts: 346	Re: Rebreather Comparison Chart Quote: (Originally Posted by AD_ward9) EN14143 is on the internet. the Russian definition of an expert: A person who has made all possible mistakes in a very narrow field. I am getting there slowly Alex My father I recall had a similar saying, as consultant engineers concentrating on each smallest component in an overall design. As we got to understand more and more about less and less of the design, more and more time was taken up on less and less important parts of the project. “Keep this up and we will know everything there is to know about bugger all”
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19th October 2007, 15:24	#108 (permalink)
iain-hsm Custom Title Allowed! Current Rebreather/s: MK 15.X Other CCR Other SCR Other Rebreather/s: Other CCR Other SCR Join Date: Mar 2005 Location: Loughborough England uk Posts: 346	Re: Rebreather Comparison Chart Quote: (Originally Posted by PhilSiswick) This is fascinating - many thanks. What conclusions do you draw for recreational (say up to 50m diving)? A shallower change to rich mix to reduce the amount of N2 in the gas? Or do you think that the same mechanism applies to He bubbles? Cheers, Hi Phil Not to go off post, but you cant make this conclusion as it is C02 retension that is the precurser re mix I will post (new post) some of the early work in the C02 retainers later.
(Offline)

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