Diving MCCR beyond depth limits?

teksimple · 2nd July 2007, 09:12

Quote: (Originally Posted by DepthCharge)

OK, I'm curious, care to fill me ( and everyone else)in on the oxygen controller?

Sure! How about if I take it to a new thread...here.

Andy Del · 2nd July 2007, 13:08

you can have a look at this thread, which contains images of how
I got my KISS to go a bit deeper..

http://www.rebreatherworld.com/kiss-...s+modification

It's relatively easy to do, and works a treat: you just need somewhere to put the extra O2 bottle. Having said that, the same idea on a copis meg is even easier!

tibby · 2nd July 2007, 18:45

Quote: (Originally Posted by ardhill)

Thanks Dave

I am in no mad rush to get myself killed by modifying a unit and jumping into 100m of water when I am not safe in 10m on a Rebreather

I am just doing my homework and find out out what is possible. You all have reasons why you prefer one style of unit over another, I am beginning to understand what I like and don't like after looking at RBs for some time. I am just further developing my understanding and the possibilities and possible restrictions I would have if I were to go with a MCCR over ECCR. And specifically restrictions in the MCCR units I have my eye mostly on.

I have had enough incidents on OC, to not learn that being stupid under water has a tendency to shorten your life expectancy

.

I'm about where you are and I just finished reading Mastering Rebreathers by Jeff Bozanic. If you haven't read it already I would reccomend it. I think it would help a lot in understanding the differences beteen units better. It surely helped me.
Cheers,
Tibby

Janwillem Bech · 3rd July 2007, 21:03

Gas flow through an orifice

Jan Willem Bech
Rebreathers Worldwide

Janwillem Bech · 3rd July 2007, 21:04

or...

MCCR in Depth

Jan Willem Bech
Rebreathers Worldwide

ardhill · 3rd July 2007, 21:15

Thanks Jan

I was actually browsing your site when you posted those links

**Freef** · 3rd July 2007, 22:47

The quick answer is that there needs to be a certain pressure differential over an orifice to generate sonic flow.

If you are below sonic flow you are not getting the 'correct' flow of gas. The deeper you go, the higher the pressure on the 'supplied' side and the less flow you will get once you are below the threshold pressure difference.

For example, the Dolphin first stage runs at 16 bar [ish]. I get a flow of 5.8 L/min from the 60% jet. If I plug in a 9.5 bar first stage I then only get a flow of 5.8 L/min using the 40% jet, which supplies 10.4 L/min when at the correct supply pressure.

2nd July 2007, 09:12	#21 (permalink)
teksimple Enlightened Alpinist Current Rebreather/s: Sport Kiss MK 15.X Other Rebreather/s: Sport Kiss Classic Kiss Join Date: Apr 2005 Location: Back in Hawaii Posts: 495	Re: Diving MCCR beyond depth limits? Quote: (Originally Posted by DepthCharge) OK, I'm curious, care to fill me ( and everyone else)in on the oxygen controller? Sure! How about if I take it to a new thread...here. __________________ ---- _____________ "I don't know the percentage of the Internet that's valid, do you? Jesus, it's scary." - Hunter S. Thompson
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2nd July 2007, 13:08	#22 (permalink)
Andy Del Classic KISSer Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Feb 2005 Location: Australia, Sunny Sydney Posts: 410	Re: Diving MCCR beyond depth limits? you can have a look at this thread, which contains images of how I got my KISS to go a bit deeper.. http://www.rebreatherworld.com/kiss-...s+modification It's relatively easy to do, and works a treat: you just need somewhere to put the extra O2 bottle. Having said that, the same idea on a copis meg is even easier! __________________ Yellow - the colour of greatness!
(Online)

2nd July 2007, 18:45	#23 (permalink)
tibby untitled Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: May 2007 Location: Salt Lake City, UT Posts: 336	Re: Diving MCCR beyond depth limits? Quote: (Originally Posted by ardhill) Thanks Dave I am in no mad rush to get myself killed by modifying a unit and jumping into 100m of water when I am not safe in 10m on a Rebreather I am just doing my homework and find out out what is possible. You all have reasons why you prefer one style of unit over another, I am beginning to understand what I like and don't like after looking at RBs for some time. I am just further developing my understanding and the possibilities and possible restrictions I would have if I were to go with a MCCR over ECCR. And specifically restrictions in the MCCR units I have my eye mostly on. I have had enough incidents on OC, to not learn that being stupid under water has a tendency to shorten your life expectancy . I'm about where you are and I just finished reading Mastering Rebreathers by Jeff Bozanic. If you haven't read it already I would reccomend it. I think it would help a lot in understanding the differences beteen units better. It surely helped me. Cheers, Tibby
(Offline)

3rd July 2007, 21:03	#24 (permalink)
Janwillem Bech New Member Current Rebreather/s: Inspiration Classic Other CCR Other SCR Other Rebreather/s: Other CCR Other SCR Join Date: Feb 2005 Location: Netherlands Posts: 89	Re: Diving MCCR beyond depth limits? Gas flow through an orifice Jan Willem Bech Rebreathers Worldwide
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3rd July 2007, 21:04	#25 (permalink)
Janwillem Bech New Member Current Rebreather/s: Inspiration Classic Other CCR Other SCR Other Rebreather/s: Other CCR Other SCR Join Date: Feb 2005 Location: Netherlands Posts: 89	Re: Diving MCCR beyond depth limits? or... MCCR in Depth Jan Willem Bech Rebreathers Worldwide
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3rd July 2007, 21:15	#26 (permalink)
ardhill New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Feb 2007 Location: Belfast, Northern Ireland Posts: 46	Re: Diving MCCR beyond depth limits? Thanks Jan I was actually browsing your site when you posted those links __________________ Paul (Note: I currently don't dive a Rebreather, but dive OC. So if anything I say about breathers sounds suspect - it probably is)
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3rd July 2007, 22:47	#27 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,356	Re: Diving MCCR beyond depth limits? The quick answer is that there needs to be a certain pressure differential over an orifice to generate sonic flow. If you are below sonic flow you are not getting the 'correct' flow of gas. The deeper you go, the higher the pressure on the 'supplied' side and the less flow you will get once you are below the threshold pressure difference. For example, the Dolphin first stage runs at 16 bar [ish]. I get a flow of 5.8 L/min from the 60% jet. If I plug in a 9.5 bar first stage I then only get a flow of 5.8 L/min using the 40% jet, which supplies 10.4 L/min when at the correct supply pressure. __________________ David. Currently owner of two differently sized ankles. Last edited by Freef : 3rd July 2007 at 22:48. Reason: clarity
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