Oxygen generator - generating higher PSI for storage.

[Dr. Lecter]

To keep things in perspective, argon is roughly 2.33 times as narcotic as nitrogen and the air used in blending any of these mixes is alread ~1% argon. 4% argon in 96% O2 is still a rounding error.

 

[lonebrave]

To keep things in perspective, argon is roughly 2.33 times as narcotic as nitrogen and the air used in blending any of these mixes is alread ~1% argon. 4% argon in 96% O2 is still a rounding error.

So if we say N is narcotic at 30msw (3.16 PN), then we're trying to avoid a situation where PAr is ~1.35...at 4% (max FAr in the scenario we're discussing), that means breathing 96% 02/4% Ar at 572.5m. I'm not seeing a problem here.

To the OP...sorry for the hijack. Hopefully you still get some more input.

 

[DepthCharge]

My point is what is the relationship between pO2, pN2, pCO2, and pAr? The point is no one knows. High pO2 & high pCO2 are thought to be antagonistic towards each other. So why throw in a gas that is known to be more of a problem.
4% at the surface doesn't sound like much.......but remember partial pressure increases with depth and so do the effects.
Later,
John

 

[Dr. Lecter]

My point is what is the relationship between pO2, pN2, pCO2, and pAr? The point is no one knows. High pO2 & high pCO2 are thought to be antagonistic towards each other. So why throw in a gas that is known to be more of a problem.

Translation: I have no idea how 4% argon could be harmful in a breathing mix with a MOD of 20', so I'll just claim it could be a problem and see if I can shift the burden to others to disprove my unsubstantiated claim. I definitely won't mention that air already contains ~1% Ar.

4% at the surface doesn't sound like much.......but remember partial pressure increases with depth and so do the effects.

Translation: I will ignore the fact that two people just discussed--in terms of actual numbers--how depth increasing partial pressure and narcotic effects of argon would likely not be an issue because the MOD for 96% O2 and 4%Ar is ~20', and there's already 1% Ar in breating air already. Since numbers don't appear to be my friend at this point, I will just say it's bad and move on.

All that said, maybe the issue would change if you're considering using the 96/4 mix with a CCR. I just don't know enough about rebreathers to say. But for OC use, it's hard to see how a max 3% increase in Ar would matter given the MODs involved.

 

[iain/hsm]

Translation: I have no idea how 4% argon could be harmful in a breathing mix with a MOD of 20', so I'll just claim it could be a problem and see if I can shift the burden to others to disprove my unsubstantiated claim.

Gentlemen. The penalty for hijacking threads in the compressor section of the forum is that we get to ask you questions.

Breathing pure oxygen, closed circuit in a rebreather such as the Draeger LAR V is one of the reasons why cylinders marked "Diving Oxygen" (under EN 8478) are alway from gaseous oxygen derived from liquid production.
Same reason for deep saturation diving in oxygen make up

Specifically pure oxygen rebreathers that use the metabolic consumption rate of oxygen being consumed from the rebreather bag and that initiate mechanically the refill of the bag are susceptible to inert gas build up from the bottle into the breathing bag, increasing in concentration throughout the dive duration.

You are in effect making your own inert gas concentrator. And another good reason to always "flush the bag" prior to accent.

In mitigation the Maximum Operating Depth MOD with oxygen of say 25 FSW 6MSW will limit the narcotic effect, while and Total Time under Pressure TTUP breathing oxygen metabolically (around 180 minutes) limits the level of inert gas generated.

Now your penalty for hijacking a perfectly good thread on compressors is to work out this Argon mass.

The maths is using a oxygen metabolic uptake of 1 LPM at rest from a breathing rate of say 20 BPM / 2.0 litres (40 RMV) assume the bag at say 10 cm H20 pressure being never fully inflated of deflated and a tidal loop of say 2.5 litres from a breathing bag that is 8.2 litres fully inflated.

The bottle contains 1.5 x 200barg litres 300 litres of which 4% is Argon and the regulator drive pressure 66psi over ambient.

Forget PPC02, canister duration and water temperature for the purposes of the question Im not that hard on folk. I look forward to a properly worked out answer from each and every one of you, as is the custom of the compressor section of this forum. Iain Middlebrook

 

[Dr. Lecter]

The penalty for using "maths" as a noun in any forum is a snarky yet on-point response, such as:

All that said, maybe the issue would change if you're considering using the 96/4 mix with a CCR. I just don't know enough about rebreathers to say. But for OC use, it's hard to see how a max 3% increase in Ar would matter given the MODs involved.

 

[DepthCharge]

Well each to there own.....didn't think that people would try to make it a more personal attack than attacking the facts. Anyway, I didn't work out the numbers because frankly I'm not that interested. I was trying to make the point that why inculde a less than desirable gas in what you're breathing? Just doesn't make any sence to me. When I learned about diving the focus was on minimizing risk. To me that is adding risk that can be avoided.
Anyway hope you have many safe dives
John

 

[manni-yunk]

Well each to there own.....didn't think that people would try to make it a more personal attack than attacking the facts. Anyway, I didn't work out the numbers because frankly I'm not that interested. I was trying to make the point that why inculde a less than desirable gas in what you're breathing? Just doesn't make any sence to me. When I learned about diving the focus was on minimizing risk. To me that is adding risk that can be avoided.
Anyway hope you have many safe dives
John

I dont think people realize the % of argon in most tanks is already approaching 1%. 4% isnt anything Im concerned with at all.

 

[iain/hsm]

I trust I'm not too hard here, this is not an attack but sadly by your stated "lack of interest" you show to have totally miss understood the point.Thereby the risk that you (and others) with incorrect statements cause and the resultant unforeseen consequence from them remain, unless IMHO challenged.

Further the post goes off topic and nonsense is blended with informed knowledge to a point that either someone "cleans" up the nonsense or it remains to become in some ways accepted fact. Im sure you see my point here.

For the benefit of others reading the OP required an oxygen concentrator and now were off on the argon question, All the "Argon" posters here just need to appreciate the difference between a 4% inert gas in an open circuit scuba set up, against 4% in a pure oxygen closed circuit set up. Further when did this 4% inert gas become argon (fact) LOL

Granted its an interesting subject but it clogs up the OP's original question.

If as you state when you learned diving the focus was on minimising risk I agree so we need IMHO to work out those numbers to assure ourselves and others reading of some pretty substantive risk avoidance. We can also highlight the risk of inert gas in certain breathing applications, and not let open circuit cloud the risk here.

Production of oxygen by the PSA method for producing nitrox IMHO needs both the producers of the gas product and divers using it to appreciate the application of that product it's limitations and its applications. When compared say to pure oxygen derived from a liquid distillate for example, closed circuit to semi closed, open circuit to PP02 controlled.

It's subtle detailed and contains mathematics, but I can assure you once grasped it's knowledge gained that will stick and make sense. Once again no attack, nothing personal my statement is pretty general. Iain Middlebrook

 

[DepthCharge]

Ian, I wasn't referring to you, sorry you got that impression. Again as I'm primarily a RB diver (99%) I tend to look at things a bit more critically. I actually looked into a concentrator years ago but found the best would only produce about 93% O2 with the balance being Ar. ( actually a quick look today and the vast majority still only claim 93%......so 96% maybe a bit.........optimistic).
As you know using a gas that has any type of "contamination" in it in a rebreather is a death wish.
To explain for those that don't know much about rebreathers:
Once a RB diver reaches the depth they want, no further dilutent is added, more or less stays constant (except what is entering the "tissue compartments". The only thing that gets added is O2. Now if your O2 is contaminated, that also gets added. So the average O2 consumption is about 1L/min (actually a bit less, but this makes the math a bit easier). So if you have 4% of a contaminent you have 960 ml O2 and 40 ml of contaminent added. Now you metabloize the O2 but leave the contaminate, so the next minute you've added the mext 960 ml and the 40 ml, but now there is 80 ml of the contaminate in the loop. Now this happens every minute.
It's not uncommon to do 2-4+ dives on a RB, so I'll let someone else finish that math. Figure a loop volume of 10L.
Now there are ways that it can be done, freq. dilutent flushes, but that's not the point of a RB.
And yes it's probably ok to breathe some, I'm sure people do it all the time, but it's not for me. Maybe my personal standards are a bit strict, but they work for me.
Later,
John