60 orifice cheating

***sadave*** · 11th October 2006, 02:11

Have a look at Dave Teubner's (dteubner on RBW) site, he used to dive a Ray before he got his Sports Kiss, and has done quite a bit of work on flow rates, jets, etc etc etc...

He's a very smart man...

Research etc

I think the one you want is loop 02 percentage calculator for SCR's... But i'm sure you'll find some of the others usefull too...

grandizer52 · 11th October 2006, 07:09

Yea the dark side....since the dawn of time...sometime in the 70's when i was faced my failure in the cave (womb) cheat!!!!! has anyone wasted the $$$ on that 100% orifice? (since ron said) i'm starting the conversion this weekend
stay tuned
laytah
steve

silent running · 11th October 2006, 08:06

It was a long time ago, but I used to use a mismatch orifice/nitrox mix. I think it was a 60% orifice with 38% nitrox. Max depth 170ft FO2 of 26% or so, can't remember all the math/flow rates. It worked well beyond 100ft -venting say every 6-8 breaths if I remember correctly. But shallow and under higher work loads, I had problems. The Drager demand valves on the 4 different units I used were way too tight and after a hypoxic event in high current at 15-20ft, had to BO and surface, got blown pretty far off the dive site and sat for a while before the RIB found me. All the units were rentals dived and maintained by the owners, and I found a big variance in the flow rates of all the 60% orifices I used. This, and the lousy demand/bypass valve and the lack off efficiency turned me off SCR as more simple alternative to CCR. But there were very few production CCRs back then-1998.

I now own a Prism and I'm very happy I went CCR. I find it at least as simple and it has way more advantages than a mass flow sonic orifice SCR. -Andy

pirateeye · 11th October 2006, 13:15

I woud like to see the chart also.

jar_uk1 · 11th October 2006, 18:53

Quote: (Originally Posted by pirateeye)

I woud like to see the chart also.

I found the original link, I can take no credit or blame for it, but I found it useful.

http://www.airheadsscuba.com/inspired.html

ther is some other inttereting stuff onn the other pages there. It took me a while to find the link as I was given a hard copy of tthe page originally.

I notice there is a small difference in the figures for the flow rates and the figures I have, but they are tiny and I dont think my flow meter resolves ANYWHERE near the accuracy needed to tell the difference! so i could not tell you what the REAL flow rate is to 1/10 L per min

John R

4ster · 12th October 2006, 02:57

Oh hell, I wasn't going to put this up.

On the otherhand the attached pdf might be useful to someone. I print it double sided then laminate it and stuff it in with the spare parts.

Double check the MODs. I think depth in feet, I just converted the tables to meters last night and havn't had a chance to check the new MODs. If someone spots an error, please let me know.

Steve

grandizer52 · 13th October 2006, 05:43

So going conversion...what should i do as...Step 1)

Deepthought · 13th October 2006, 20:21

Attached is a copy of the O2 concentration table from the NRC workbook

Its a good illustration of how different your breathing mix can be from that in the tank. Ideally you calculate MOD and CNS O2 loading based on the tank mix but remember that your non deco limit is lower because you are actually breathing a 'weaker' nitrox mix than the tank.

Shows why being able to monitor pO2 is not really an optional extra.

Cheers

Andy

grandizer52 · 14th October 2006, 05:22

This is all good info,
I was at work and tore into a LAR V man is that simple... where can i get a kiss valve to start? it's not listed on the jetsam site...
thanx

laytah
steve

**Freef** · 21st October 2006, 20:10

http://www.rebreatherworld.com/semi-...culations.html

Follow the discussion as well for soem 'hot under the collar' entertainment.

Email me/PM me your email address for some further spreadsheets.

11th October 2006, 02:11	#11 (permalink)
*sadave* Administrator Current Rebreather/s: Sport Kiss Other Rebreather/s: Not Bought Yet Classic Kiss Join Date: Jun 2005 Location: Brisbane, Queensland Posts: 1,131	Re: 60 orifice cheating Have a look at Dave Teubner's (dteubner on RBW) site, he used to dive a Ray before he got his Sports Kiss, and has done quite a bit of work on flow rates, jets, etc etc etc... He's a very smart man... Research etc I think the one you want is loop 02 percentage calculator for SCR's... But i'm sure you'll find some of the others usefull too... __________________ Wave!
(Offline)

11th October 2006, 07:09	#12 (permalink)
grandizer52 Sport Kiss & Shearwater Current Rebreather/s: Sport Kiss Other CCR Home Build Other Rebreather/s: Not Bought Yet Sport Kiss Classic Kiss MK 15.X Other CCR Home Build Join Date: May 2006 Location: pearl city hawaii EARTH moving to Iscandar Posts: 254	Re: 60 orifice cheating Yea the dark side....since the dawn of time...sometime in the 70's when i was faced my failure in the cave (womb) cheat!!!!! has anyone wasted the $$$ on that 100% orifice? (since ron said) i'm starting the conversion this weekend stay tuned laytah steve
(Offline)

11th October 2006, 08:06	#13 (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: 1,873	Re: 60 orifice cheating It was a long time ago, but I used to use a mismatch orifice/nitrox mix. I think it was a 60% orifice with 38% nitrox. Max depth 170ft FO2 of 26% or so, can't remember all the math/flow rates. It worked well beyond 100ft -venting say every 6-8 breaths if I remember correctly. But shallow and under higher work loads, I had problems. The Drager demand valves on the 4 different units I used were way too tight and after a hypoxic event in high current at 15-20ft, had to BO and surface, got blown pretty far off the dive site and sat for a while before the RIB found me. All the units were rentals dived and maintained by the owners, and I found a big variance in the flow rates of all the 60% orifices I used. This, and the lousy demand/bypass valve and the lack off efficiency turned me off SCR as more simple alternative to CCR. But there were very few production CCRs back then-1998. I now own a Prism and I'm very happy I went CCR. I find it at least as simple and it has way more advantages than a mass flow sonic orifice SCR. -Andy
(Offline)

11th October 2006, 13:15	#14 (permalink)
pirateeye New Member Current Rebreather/s: Dolphin Other Rebreather/s: Not Bought Yet Dolphin Join Date: Aug 2006 Location: New Hampshire Posts: 49	Re: 60 orifice cheating I woud like to see the chart also. __________________ Why Buy It When You Can Spend More to Build It
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11th October 2006, 18:53	#15 (permalink)
jar_uk1 RBW Member Current Rebreather/s: Inspiration Vision Dolphin Other Rebreather/s: Dolphin Join Date: Dec 2005 Location: Bracknell, UK Posts: 69	Re: 60 orifice cheating Quote: (Originally Posted by pirateeye) I woud like to see the chart also. I found the original link, I can take no credit or blame for it, but I found it useful. http://www.airheadsscuba.com/inspired.html ther is some other inttereting stuff onn the other pages there. It took me a while to find the link as I was given a hard copy of tthe page originally. I notice there is a small difference in the figures for the flow rates and the figures I have, but they are tiny and I dont think my flow meter resolves ANYWHERE near the accuracy needed to tell the difference! so i could not tell you what the REAL flow rate is to 1/10 L per min John R
(Offline)

13th October 2006, 05:43	#17 (permalink)
grandizer52 Sport Kiss & Shearwater Current Rebreather/s: Sport Kiss Other CCR Home Build Other Rebreather/s: Not Bought Yet Sport Kiss Classic Kiss MK 15.X Other CCR Home Build Join Date: May 2006 Location: pearl city hawaii EARTH moving to Iscandar Posts: 254	Re: 60 orifice cheating So going conversion...what should i do as...Step 1)
(Offline)

14th October 2006, 05:22	#19 (permalink)
grandizer52 Sport Kiss & Shearwater Current Rebreather/s: Sport Kiss Other CCR Home Build Other Rebreather/s: Not Bought Yet Sport Kiss Classic Kiss MK 15.X Other CCR Home Build Join Date: May 2006 Location: pearl city hawaii EARTH moving to Iscandar Posts: 254	Re: 60 orifice cheating This is all good info, I was at work and tore into a LAR V man is that simple... where can i get a kiss valve to start? it's not listed on the jetsam site... thanx laytah steve Last edited by grandizer52 : 15th October 2006 at 10:39. Reason: can spell
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21st October 2006, 20:10	#20 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,427	Have a look at... http://www.rebreatherworld.com/semi-...culations.html Follow the discussion as well for soem 'hot under the collar' entertainment. Email me/PM me your email address for some further spreadsheets. __________________ David. Diving the mahogany rebreather.
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