Everest Climber

spinflyer · 25th May 2007, 01:09

Quote: (Originally Posted by Duncan Price)

This thread has got me thinking (danger). Several years ago I gave a presentation on my pendulum O2 rig at a cave rescue meeting on foul air underground. On Tuesday night we were "dry" caving and encountered high CO2 at the bottom due to farmyard effluent (known as "cowsh" in the caving sphere). Am now thinking along the lines of a very lightweight O2 rig (or possibly just a CO2 filter) for such situations.

I am planning on visiting a cave with known CO2 problems - there's a sump at the bottom to dive but I'm also minded to come prepared for above water situations.

Either I knock up a full O2 rebreather (v. small scrubber and fed from an ABLJ cylinder) or breathe in cave air thru an open scrubber and vent back to the cave. For the latter I could introduce a small "leak" of O2 into the inhale side to compensate for any reduced O2 in the cave air - the flow would be miniscule so going fully closed (i.e fitting a counterlung) would not really be an advantage. Basically its a CO2 gas mask with boosted O2. Making it "open" would mean that it could not be used for diving and would prevent the user from getting too adventurous. An O2 sensor would be a benefit - maybe its an application for a simple HUD which goes red if the ppO2 drops below 0.17?

Comments welcome.

Very interesting probem. Since the scrubber will react with all CO2 present and quickly be expended I would put a simple flap on the inlet side and a one way valve to send expired breaths out. Heat will be a challenge. Since 5% CO2 is all you would normally be trying to absorb in a rebreather circuit I'm not sure at what percentage of CO2 the standard scrubber would be overwhelmed. Very interesting.

Duncan Price · 25th May 2007, 10:56

Quote: (Originally Posted by spinflyer)

Very interesting probem. Since the scrubber will react with all CO2 present and quickly be expended I would put a simple flap on the inlet side and a one way valve to send expired breaths out. Heat will be a challenge. Since 5% CO2 is all you would normally be trying to absorb in a rebreather circuit I'm not sure at what percentage of CO2 the standard scrubber would be overwhelmed. Very interesting.

I think that the cave air _could_ contain more CO2 than in expired air and that it might be more efficient to make a fully closed system rather than try to scrub the cave air.

jaap · 25th May 2007, 12:56

Quote: (Originally Posted by spinflyer)

A potassium super-oxide system was experimented with several decades ago.
Closed circuit oxygen system, high altitude oxygen
The real issue seems to be weight. Bottled O2 and a CO2 scrubber seems to provide the best weight benefit. Some quick calculations indicated that the weight necessary to sustain a standard Everest climb profile would require to much weight.

I am not familiar with the emerging technologies you mentioned but I would welcome any input. Thanks.

OK, so a LiOH and composite bottled O2 system would be lighter? I imagine another advantage of the peroxide things is the heat that is also released.

Other things could be portable O2 generators. There is alot of things going on in the prototyp stage commercializing very light portable less energy demanding reversible O2-adsorbing materials. Combined with solar panels and batteries this could give enough O2 without the need for bringing tanks along. Possibly even enough to not bother about a scrubber.

I know a little about these "new"-materials but I'm not sure if the ones working on this appreciate spreading too much info.

Yes I know the commercial ones that are avaliable today are too power consuming.

shutupanddive · 25th May 2007, 18:44

Hey it's Jeff from Micropore. We just completed tetsing of our cartridge on one of our rebreathers on Everest last week, Check out
http://www.xtreme-everest.co.uk/news_detail.php?newsid=594

There are many issues, one of the largest being freezing and thawing. The cartridge works well under these conditions and fires up instantly.
One of the other big issues is there can be no counterlung as it will freeze together...
O2 saturation levels were much higher than in OC systems,something the medical world is extremely excited about.

Best regards, Jeff

spinflyer · 25th May 2007, 21:11

Hey Jeff,

I wondered how they had done with their system. I had offered some help at one point but they seemed concerned about patents, commerical prospects, etc. (Like there is any market!) I guess they figured out the rebreather bag was a non-starter. We have now solved that problem - of course that leads to different problems.

Bud

E-man · 26th May 2007, 11:43

A small note against a pendulum rebreather. Once acclimated to altitude the body becomes much more susceptible to CO2.

25th May 2007, 01:09	#21 (permalink)
spinflyer New Member Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2007 Location: Georgia Posts: 5	Re: Everest Climber Quote: (Originally Posted by Duncan Price) This thread has got me thinking (danger). Several years ago I gave a presentation on my pendulum O2 rig at a cave rescue meeting on foul air underground. On Tuesday night we were "dry" caving and encountered high CO2 at the bottom due to farmyard effluent (known as "cowsh" in the caving sphere). Am now thinking along the lines of a very lightweight O2 rig (or possibly just a CO2 filter) for such situations. I am planning on visiting a cave with known CO2 problems - there's a sump at the bottom to dive but I'm also minded to come prepared for above water situations. Either I knock up a full O2 rebreather (v. small scrubber and fed from an ABLJ cylinder) or breathe in cave air thru an open scrubber and vent back to the cave. For the latter I could introduce a small "leak" of O2 into the inhale side to compensate for any reduced O2 in the cave air - the flow would be miniscule so going fully closed (i.e fitting a counterlung) would not really be an advantage. Basically its a CO2 gas mask with boosted O2. Making it "open" would mean that it could not be used for diving and would prevent the user from getting too adventurous. An O2 sensor would be a benefit - maybe its an application for a simple HUD which goes red if the ppO2 drops below 0.17? Comments welcome. Very interesting probem. Since the scrubber will react with all CO2 present and quickly be expended I would put a simple flap on the inlet side and a one way valve to send expired breaths out. Heat will be a challenge. Since 5% CO2 is all you would normally be trying to absorb in a rebreather circuit I'm not sure at what percentage of CO2 the standard scrubber would be overwhelmed. Very interesting.
(Offline)

25th May 2007, 10:56	#22 (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	Re: Everest Climber Quote: (Originally Posted by spinflyer) Very interesting probem. Since the scrubber will react with all CO2 present and quickly be expended I would put a simple flap on the inlet side and a one way valve to send expired breaths out. Heat will be a challenge. Since 5% CO2 is all you would normally be trying to absorb in a rebreather circuit I'm not sure at what percentage of CO2 the standard scrubber would be overwhelmed. Very interesting. I think that the cave air _could_ contain more CO2 than in expired air and that it might be more efficient to make a fully closed system rather than try to scrub the cave air.
(Offline)

25th May 2007, 12:56	#23 (permalink)
jaap Normal people worry me Current Rebreather/s: Classic Kiss Other CCR RB80 / Clone Ray Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Ray Other SCR Home Build Join Date: Jun 2005 Location: Stockholm Sweden Posts: 452	Re: Everest Climber Quote: (Originally Posted by spinflyer) A potassium super-oxide system was experimented with several decades ago. Closed circuit oxygen system, high altitude oxygen The real issue seems to be weight. Bottled O2 and a CO2 scrubber seems to provide the best weight benefit. Some quick calculations indicated that the weight necessary to sustain a standard Everest climb profile would require to much weight. I am not familiar with the emerging technologies you mentioned but I would welcome any input. Thanks. OK, so a LiOH and composite bottled O2 system would be lighter? I imagine another advantage of the peroxide things is the heat that is also released. Other things could be portable O2 generators. There is alot of things going on in the prototyp stage commercializing very light portable less energy demanding reversible O2-adsorbing materials. Combined with solar panels and batteries this could give enough O2 without the need for bringing tanks along. Possibly even enough to not bother about a scrubber. I know a little about these "new"-materials but I'm not sure if the ones working on this appreciate spreading too much info. Yes I know the commercial ones that are avaliable today are too power consuming. __________________ My initials: JAAP Last edited by jaap : 25th May 2007 at 13:00.
(Online)

25th May 2007, 21:11	#25 (permalink)
spinflyer New Member Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2007 Location: Georgia Posts: 5	Re: Everest Climber Hey Jeff, I wondered how they had done with their system. I had offered some help at one point but they seemed concerned about patents, commerical prospects, etc. (Like there is any market!) I guess they figured out the rebreather bag was a non-starter. We have now solved that problem - of course that leads to different problems. Bud
(Offline)

26th May 2007, 11:43	#26 (permalink)
E-man On the loop! Current Rebreather/s: Inspiration Classic Optima Other Rebreather/s: Titan Join Date: Sep 2005 Location: Eastern Coast ;) Posts: 212	Re: Everest Climber A small note against a pendulum rebreather. Once acclimated to altitude the body becomes much more susceptible to CO2.
(Offline)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode