Regenerating sorb?

Andy M · 20th March 2005, 12:07

http://www.hsssi.com/Applications/Sp...O2Removal.html

Seems the ISS astronauts use regenerating metal oxide sorb in their rebreathers.

Fascinating. Can we visualise dive centres one day having sorb regenerators installed.

Judging by the power requirements for this unit, I think it is currently cheaper for us to buy lime and throw it away afterwards...

Pelagian · 20th March 2005, 12:37

Do you know what exactly the absorbent media is?

Metal oxide is a little vague.

Cheers

Seb

Mark Chase · 20th March 2005, 16:09

Quote: (Originally Posted by Pelagian)

Do you know what exactly the absorbent media is?

Metal oxide is a little vague.

Cheers

Seb

Lithiam Hydroxide at a guess

ATB

Mark Chase

Pelagian · 20th March 2005, 16:25

Not sure I would be comfortable with Lithium Hydroxide in a wet envrionment.

Perhaps with the Hydrophobic Membrane canister from CIS.

Cheers

***schford*** · 20th March 2005, 16:39

And doesn't that fit in what you dive Seb

***EBT*** · 20th March 2005, 18:37

Its not lithium hydroxide, if you read the article it explains that they moved away from that

Mark Chase · 20th March 2005, 18:45

The extend air cartridges fro the insp and other CCR are Lithiam Hydroxide I think. This probably explains the £300 scrubber can upgrade before you can use them

ATB

Mark Chase

***caveseeker7*** · 20th March 2005, 19:10

Quote: (Originally Posted by Mark Chase)

The extend air cartridges fro the insp and other CCR are Lithiam Hydroxide I think. This probably explains the £300 scrubber can upgrade before you can use them

I'm not sure exactly what (or whose) absorbant material Micropore uses, but I am pretty sure it's not lithium hydroxide. Lithium hydroxide is an extremely powerfull alkali that is considerably more efficient than soda limes and works well in extreme cold temperatures, hence its use in space. But the dust of it is also extremely corrosive and very dangerous when inhaled and the resulting caustic cocktail when mixed in water likewise. It is hardly ever used in diving applications, and the only rebreather manufaturer that even mentions it for use as I recall was indeed Cis-Lunar. I discussed the cartridges with Jeff Bozanic, who is a big proponent of the idea and uses them in his SCRs. He flooded a cannister almost entirely, bailed out, dried the cartridge and used it again. Not sure this is such a good idea, but he was happy as a clam. I rather doubt he would have ever used the cartridges again had they LiOH attached as absorbant.

The reason for the Micropore replacement cannister for the Dolphin is the stock cannister's oval shape, it just doesn't fit the cartridge. Neither does the Azimuth's radial cannister. For use with the Inspirations only adapters are needed to hold the cartridge in place and seal against gas bypassing. However, from what I've been told the cartridge works best with a cannister designed for it, which may well be the reason the adapters for the Inspiration aren't on the market yet. They have been shown at dive shows and used in the TV show Deep Sea Detectives.

Pelagian · 20th March 2005, 19:22

The Extendair cartridges are impregnated with Calcium and Sodium Hyrdoxide, the bulk being calcium hyroxide.

Lithium is too dangerous when exposed to water for most companies liabilty coverage to accept, as a civilian product.

While it is a much more efficient sorb, I just can't justify the risk or expense out here when, the warm waters and easy diving mean 5.5lbs of 812 Sofnolime will last me 5 hours.

I'm still waiting for Steve to come up with the price for the CIS canisters he sais they'll be producing in June.

It'll be a very sweet upgrade along with the new Shearwater elcetronics.

If I ever move to cold water I might grab the neoprene lungs as well.

Cheers

Duncan Price · 21st March 2005, 09:23

Quote: (Originally Posted by Pelagian)

Do you know what exactly the absorbent media is?

Metal oxide is a little vague.

Cheers

Seb

Silver and zinc oxide. If you heat them up under vacuum (plenty of that around in space) then the CO2 is removed and the scrubber regenerated.

There are also amine based systems which can be regenerated as well.

The Russians used superoxide (the stuff that releases O2 when it binds CO2) - catches fire (MIR fire) when wet.

20th March 2005, 12:07	#1 (permalink)
Andy M Dude Current Rebreather/s: Home Build Other Rebreather/s: Sport Kiss Home Build Join Date: Mar 2005 Location: Cambridge, UK Posts: 423	Regenerating sorb? http://www.hsssi.com/Applications/Sp...O2Removal.html Seems the ISS astronauts use regenerating metal oxide sorb in their rebreathers. Fascinating. Can we visualise dive centres one day having sorb regenerators installed. Judging by the power requirements for this unit, I think it is currently cheaper for us to buy lime and throw it away afterwards...
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20th March 2005, 12:37	#2 (permalink)
Pelagian Multi-Circuit Meg Monkey! Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Optima Join Date: Feb 2005 Location: Leeds, England Posts: 282	Do you know what exactly the absorbent media is? Metal oxide is a little vague. Cheers Seb __________________ 'Because... I was Inverted!'
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20th March 2005, 16:09	#3 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,700	Quote: (Originally Posted by Pelagian) Do you know what exactly the absorbent media is? Metal oxide is a little vague. Cheers Seb Lithiam Hydroxide at a guess ATB Mark Chase __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
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20th March 2005, 16:25	#4 (permalink)
Pelagian Multi-Circuit Meg Monkey! Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Optima Join Date: Feb 2005 Location: Leeds, England Posts: 282	Not sure I would be comfortable with Lithium Hydroxide in a wet envrionment. Perhaps with the Hydrophobic Membrane canister from CIS. Cheers __________________ 'Because... I was Inverted!'
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20th March 2005, 16:39	#5 (permalink)
*schford* Despotic Overlord Current Rebreather/s: Megalodon Sport Kiss Other Rebreather/s: Join Date: Jan 2005 Location: London, UK Posts: 3,562	And doesn't that fit in what you dive Seb
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20th March 2005, 18:37	#6 (permalink)
*EBT* Apprentice Luddite Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: UK, Brighton Posts: 1,970	Its not lithium hydroxide, if you read the article it explains that they moved away from that __________________ Eagles May Soar, but weasels don't get sucked into jet engines! Rebreather World Terms of service Real diving t-shirts for real divers
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20th March 2005, 18:45	#7 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,700	The extend air cartridges fro the insp and other CCR are Lithiam Hydroxide I think. This probably explains the £300 scrubber can upgrade before you can use them ATB Mark Chase __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
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20th March 2005, 19:10	#8 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,451	Quote: (Originally Posted by Mark Chase) The extend air cartridges fro the insp and other CCR are Lithiam Hydroxide I think. This probably explains the £300 scrubber can upgrade before you can use them I'm not sure exactly what (or whose) absorbant material Micropore uses, but I am pretty sure it's not lithium hydroxide. Lithium hydroxide is an extremely powerfull alkali that is considerably more efficient than soda limes and works well in extreme cold temperatures, hence its use in space. But the dust of it is also extremely corrosive and very dangerous when inhaled and the resulting caustic cocktail when mixed in water likewise. It is hardly ever used in diving applications, and the only rebreather manufaturer that even mentions it for use as I recall was indeed Cis-Lunar. I discussed the cartridges with Jeff Bozanic, who is a big proponent of the idea and uses them in his SCRs. He flooded a cannister almost entirely, bailed out, dried the cartridge and used it again. Not sure this is such a good idea, but he was happy as a clam. I rather doubt he would have ever used the cartridges again had they LiOH attached as absorbant. The reason for the Micropore replacement cannister for the Dolphin is the stock cannister's oval shape, it just doesn't fit the cartridge. Neither does the Azimuth's radial cannister. For use with the Inspirations only adapters are needed to hold the cartridge in place and seal against gas bypassing. However, from what I've been told the cartridge works best with a cannister designed for it, which may well be the reason the adapters for the Inspiration aren't on the market yet. They have been shown at dive shows and used in the TV show Deep Sea Detectives. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
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20th March 2005, 19:22	#9 (permalink)
Pelagian Multi-Circuit Meg Monkey! Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Sport Kiss Optima Join Date: Feb 2005 Location: Leeds, England Posts: 282	The Extendair cartridges are impregnated with Calcium and Sodium Hyrdoxide, the bulk being calcium hyroxide. Lithium is too dangerous when exposed to water for most companies liabilty coverage to accept, as a civilian product. While it is a much more efficient sorb, I just can't justify the risk or expense out here when, the warm waters and easy diving mean 5.5lbs of 812 Sofnolime will last me 5 hours. I'm still waiting for Steve to come up with the price for the CIS canisters he sais they'll be producing in June. It'll be a very sweet upgrade along with the new Shearwater elcetronics. If I ever move to cold water I might grab the neoprene lungs as well. Cheers __________________ 'Because... I was Inverted!'
(Online)

21st March 2005, 09:23	#10 (permalink)
Duncan Price Sump Monster Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Feb 2005 Location: Wells, Somerset, UK Posts: 335	Quote: (Originally Posted by Pelagian) Do you know what exactly the absorbent media is? Metal oxide is a little vague. Cheers Seb Silver and zinc oxide. If you heat them up under vacuum (plenty of that around in space) then the CO2 is removed and the scrubber regenerated. There are also amine based systems which can be regenerated as well. The Russians used superoxide (the stuff that releases O2 when it binds CO2) - catches fire (MIR fire) when wet.
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