2 O2 and Diluent inflators on 1 counter lung

[wazza]

Dear friends

I am just wondering if any one can explain this picture for me, why this guy is using 2 O2 and Diluent inflators on his counter lungs?

I know he is using it for 3mix but what I want to know is why and how he is dealing with it and what is the procedure of 3mix with the machine

Second question where can I fined the constant PPO2 us navy tables to plan a dive with the ccr.

Thanks one more time for the time and help.

 

[teksimple]

First question is a stumbler for me. Will wait to hear the answer from someone else.

Second question. Why use the Navy PPO2 Tables? You can get them in the Navy diving manual at Supsalv.org, (http://supsalv.org/00c3_publications.asp?destPage=00c3&pageId=3.9) but as far as any USN tables that I have seen, you are limited to only 0.7 PPO2. In the 30's, the guidelines for Navy divers was not to exceed 2.5 PPO2, go figure.

Why not get Vplanner or GAP or Decoweenie? Make your own tables, with a better algorithm (or at least one that you can choose).

 

[wedivebc]

Dear friends

I am just wondering if any one can explain this picture for me, why this guy is using 2 O2 and Diluent inflators on his counter lungs?

I know he is using it for 3mix but what I want to know is why and how he is dealing with it and what is the procedure of 3mix with the machine

Second question where can I fined the constant PPO2 us navy tables to plan a dive with the ccr.

Thanks one more time for the time and help.

I can understand the need for offboard diluent. It allows you to change the mix during the dive. User a richer diluent during the shallower portion of the dive and your O2 solenoid fires less often. The offboard O2 must be for redundancy.
In Jeff Bonzanics mastering rebreathers book there are a few constant PO2 tables

 

[gkndivebum]

[...]Second question where can I fined the constant PPO2 us navy tables to plan a dive with the ccr. [...]

Can't help you with the picture, though the guesses rendered so far seem reasonable to
me (given that I've only had 1/2 a cup of coffee so far this morning )

Re: constant PO2 tables. IANTD has a nice set for 1.2 ATA with both air and normoxic trimix
diluent no-stop and some deco tables as well. You can get them from Dive Rite Express, but
there's bound to be someplace you can get them closer to where you are.

 

[caveseeker7]

Hi Wassim,

your first answer should be pretty much answered, 2 manual addition valves per side as redundancy (in case of manual valve, 1st stage or tank valve failure).

US NAVY constant PO2 tables come in 0.7 ata and 1.3 ata (for the MK16) only afaik, and are as all NAVY tables very agressive.

Constant pO2 tables are available from NAUI (RGBM - including the ones in Bozanic's "Mastering Rebreathers") and IANTD (VPM-B) for air and trimix diluents. You can purchase them through their websites.

Stefan

 

[wazza]

I can understand the need for offboard diluent. It allows you to change the mix during the dive. User a richer diluent during the shallower portion of the dive and your O2 solenoid fires less often. The offboard O2 must be for redundancy.
In Jeff Bonzanics mastering rebreathers book there are a few constant PO2 tables

Thanks for your answer

please can u explain it for me in more details.
Do you mean like when we dive trimix we have a travel mix and bottom mix ( in a way the inspiration is like that as well) .
And what do u mean by offboard O2.
And do u plan the dive then using a diving software and telling the software when, where and what the new mix is being changed.

Please hope u can exactly tell me how is a trimix dive with the ccr is done with more then a mix and a tank.

Thanks again

 

[nigelvh]

I am just wondering if any one can explain this picture for me, why this guy is using 2 O2 and Diluent inflators on his counter lungs?

I have two DIL injectors and one O2 injector.

If I have to switch to semiclosed bailout and plug in the stage I do not wish to unplug my working system as that deprives me of any means of injecting DIL if I break something. Having two means I have time to think, time to fix things without going OC. OK this isn't quite true now I have added the ADV.

I never quite saw the point of two oxygen injectors as I not see a plan that would call for me to carry oxygen and if I did I could inject on the DIL side. If I had two I'd probably replace the lower one with a dump valve so I could clear the gloop out of the exhale lung if it starts to mount up.

 

[wedivebc]

Thanks for your answer

please can u explain it for me in more details.
Do you mean like when we dive trimix we have a travel mix and bottom mix ( in a way the inspiration is like that as well) .
And what do u mean by offboard O2.
And do u plan the dive then using a diving software and telling the software when, where and what the new mix is being changed.

Please hope u can exactly tell me how is a trimix dive with the ccr is done with more then a mix and a tank.

Thanks again

Although I am not CCR trimix trained I will give you my best understanding of it. Your onboard gas is very limited. I carry 20cf of dil and O2 on my rebreather plus 30cf OC bailout gas as a sling. Let's say I had a failure of the o2 delivery system, could be lost gas or electronics etc. I could use my OC and bailout, but if I needed more time a better option is to run my unit as a semi closed rebreather which allows me to use my 20cf more efficiently. I could also, if I had an extra port, plug in my 30cf bailout and use it as diluent for scr bailout (offboard). Another option is to use different gasses as diluent for different legs of a dive but that is outside my level of training and maybe padiscubapro will jump in on that aspect of it.

 

[wazza]

thanks guys for the help.
I am looking for some one to do the ccr course for me, hope I can fined one as fast as I can, at least this would stop me from asking these stupid questions. anyway I just got the
TDI ccr manual and the inspiration manual form there web site and I am trying to teach my self a bout it until I take the course.
take care guy and thanks a lot.
Stefan thanks for every thing and maybe next week I will PM you.
bye for now

 

[padiscubapro]

Although I am not CCR trimix trained I will give you my best understanding of it. Your onboard gas is very limited. I carry 20cf of dil and O2 on my rebreather plus 30cf OC bailout gas as a sling. Let's say I had a failure of the o2 delivery system, could be lost gas or electronics etc. I could use my OC and bailout, but if I needed more time a better option is to run my unit as a semi closed rebreather which allows me to use my 20cf more efficiently. I could also, if I had an extra port, plug in my 30cf bailout and use it as diluent for scr bailout (offboard). Another option is to use different gasses as diluent for different legs of a dive but that is outside my level of training and maybe padiscubapro will jump in on that aspect of it.

different diluents for different legs are a waste of gas, although they could come in handy if you have to run SCR..

The biggest mistake many trimix ccr divers do is to do a loop flush with say air to "get the helium out " of the loop, and then make this change on their dive planning software (or computer) .. This gets them out of the water quicker but is ABSOLUTELY incorrect.. You are on a closed system, after a few minutes you have HELIUM IN THE LOOP!! If you do a flush with air and don't make a software change you will add a LITTLE bit of margin because the Helium will be lower than expected but IT IS THERE!