Compressor/Nitrox Questions

[Hoosier]

Please correct me if I'm wrong but the way I see this is as follows.

If I do PP mixing, which is probably the way I'm leaning, I can do that safely using the current filtration that came with the compressor. I plan on changing it very regularly to keep the air as clean and dry as possible anyway. Is this correct? Thanks for all your help.

No..... If you want PPblending, you need to get the extra filtration to get an O2 compatible air. Most people is using additional 27~32 inch chamber or two 16 inch chambers. It works for the pp blending, but isn't truly hyper filtered air. Only LF is manufacturing Hyper filter appliance at this moment.

Been there done that.

 

[Slipstrm]

That said, you don't need o2-clean air for PP maxing, since the mixing takes place upstream of the filter and the filter, lines and tank will never see anything higher then 40%.

I THINK WHAT HE MEANT TO SAY WAS IF YOU ARE PP MIXING, YOU WILL NEED O2 CLEAN AIR

 

[pescador775]

There is controversy over PP mixing and a lot of hype about filtration. If I were you I would ignore the hyper filter sales pitch and conduct mixing with the stock Bauer. Change out the cartridges per mfgr recommendations. Clean the Scuba tank after 100 fills or more frequently based on your research. PP mixing is not necessarily more "safe" than continuous flow blending. Each carries about the same risk/reward as filling the gas tank on your boat.

If you were proposing to use an older Bauer with only a condenser and cup of charcoal I would object but the modern Bauer filtration system pumps a lot less oil than suggested by CGA stds for grade "E" air.

 

[cobaltblue]

Pescador, I was kind of leaning towards what you were saying. When speaking with the folks at Bauer, I got two different messages. The first and Bauer's official stance is: No Nitrox. They don't want thier compressors having anything to do with Nitrox officially. Now, the other message was unofficial. They stated that thier air was "O2 clean" coming out of a new PO system. (remember though, no nitrox) I also got the feeling that they see no problem with continuous mixing. (remember though, no nitrox)

Basically the read I got from Bauer was they weren't real excited about someone blowing themselves or thier compressor up running 50% or 60% through it. The person I spoke with, said that some of the other companies CYA by saying the 40% rule. Bauer just chooses to say, remember, no nitrox. What that means to me, I just won't tell them that I love my new compressor and I use it for nitrox.

 

[Hoosier]

Pescador, I was kind of leaning towards what you were saying. When speaking with the folks at Bauer, I got two different messages. The first and Bauer's official stance is: No Nitrox. They don't want thier compressors having anything to do with Nitrox officially. Now, the other message was unofficial. They stated that thier air was "O2 clean" coming out of a new PO system. (remember though, no nitrox) I also got the feeling that they see no problem with continuous mixing. (remember though, no nitrox)

Basically the read I got from Bauer was they weren't real excited about someone blowing themselves or thier compressor up running 50% or 60% through it. The person I spoke with, said that some of the other companies CYA by saying the 40% rule. Bauer just chooses to say, remember, no nitrox. What that means to me, I just won't tell them that I love my new compressor and I use it for nitrox.

I am confused... You are saying two different things.

One:

PP blending doesn't matter with what the manufacture said. The compressor never meets any pure oxygen, so 40%, 50%, or 100% concern aren't relevant. Only CBing is matter with the higher oxygen concentration because you have to run the more pure oxygen to the compressor inlet.

Second:

There is a rasing issue about the Triplex filtration lifetime. Depending on the temperature, its lifetime is huge difference. I am not sure how you can control of air purity with those many factors.

If it works, it will be great to me as an owner of the same tiny Triplex system.

But, I am a little skeptical....

 

[in_cavediver]

I am confused... You are saying two different things.

One:

PP blending doesn't matter with what the manufacture said. The compressor never meets any pure oxygen, so 40%, 50%, or 100% concern aren't relevant. Only CBing is matter with the higher oxygen concentration because you have to run the more pure oxygen to the compressor inlet.

One more concern for PP blending. Fill rates. You don't want to dump air over pure o2 at a high fill rate. With a compressor, you are tied to what it delivers. If it was me, I'd want a bank bottle or 'surge' bottle or something so I could control the flow rate independently of the compressor's fill rate.

Second:

There is a rasing issue about the Triplex filtration lifetime. Depending on the temperature, its lifetime is huge difference. I am not sure how you can control of air purity with those many factors.

If it works, it will be great to me as an owner of the same tiny Triplex system.

But, I am a little skeptical....

What part of Indiana are you in again as I can't quite justify a compressor just yet........

 

[Hoosier]

One more concern for PP blending. Fill rates. You don't want to dump air over pure o2 at a high fill rate. With a compressor, you are tied to what it delivers. If it was me, I'd want a bank bottle or 'surge' bottle or something so I could control the flow rate independently of the compressor's fill rate.

Valuable point. Most people eventually end up with the banking system.


What part of Indiana are you in again as I can't quite justify a compressor just yet........

Oops! I thought you knew it...

Boiler Maker,:no

I am in the center of your rival town in the hoosier land.

 

[cobaltblue]

I am confused... You are saying two different things.

One:

PP blending doesn't matter with what the manufacture said. The compressor never meets any pure oxygen, so 40%, 50%, or 100% concern aren't relevant. Only CBing is matter with the higher oxygen concentration because you have to run the more pure oxygen to the compressor inlet.

Second:

There is a rasing issue about the Triplex filtration lifetime. Depending on the temperature, its lifetime is huge difference. I am not sure how you can control of air purity with those many factors.

If it works, it will be great to me as an owner of the same tiny Triplex system.

But, I am a little skeptical....

I tried to seperate what I was trying to say. In fact I was saying two things. First, Bauer officially wants nothing to do with their compressors and Nitrox. Second, from what information I was given, they see no problem (unofficial of course) with either PP or CB blending. The question/point I was trying to address is that from what I gather, no extra "hyper" filtration is needed to PP blend.

The more I get into this, the more I'm finding out that there are all kinds of people who want to give advice on all this and aren't doing it themselves. (I don't mean any of you) That's why I love Scubaboard. We can discuss this here with people who are doing it. Try having a discussion about this with your local dive buddies, it's good for a laugh. Thanks again for allowing me to share in this wonderful knowledge base.

 

[Hoosier]

If you search the board, you can find that I got through the same path you are taking right now. I am not an expert unlike the members who post on this thread. They are all my mentors on this matter. I think I exchanged PM almost every members who frequently post about this subject. In addition, I also contacted Airtek, Bauer, LF, scubacompressor, GMC, and many numerous experts who I got recommendation.

"no extra "hyper" filtration is needed to PP blend."

Sure, it isn't a "must have," but a recommended option. Many divers are using the stock regualtor on the deco bottle wthout having O2 cleaning. But, it isn't recommend. So, it is your choice and risk as always.. My choice was a Hyper filter even for the CBing...

 

[pescador775]

Carbon Dioxide.........1000 ppm
Carbon Monoxide.......10 ppm
Oil mist....................5 mg/m3
Volatile Hydrocarbon...25 ppm
Water......................24 ppm

The above are grade E specs for breathing air as applied to divers' compressors. Take a look at the number for volatiles, 25 ppm. It has been shown that humans can detect the common volatile toluene at 80 ppb (billion). Let's make an assumption that the odor of compressor oil aerosol can be detected at 160 ppb. That is equivalent to 0.12 mg/cubic meter. The "E" standard allows 5 mg/m3. This suggests that if one can smell oil the air is not safe for several reasons but may in fact be lower than permitted by grade E. Oil travels with water as an emulsion. One might assume that if water shows up in the tank then oil is present also, and that is not safe. No water, no oil. No smell, no oil-- or insignificant oil shall we say. Something to think about.