Pseudo Partial Pressure Blending using HP 300 cuft rented tank?

[Basking Ridge Diver]

Doesn't seem too difficult. Once that is made up the ongoing part of o2 cleaning valves and tanks would have to be done but that isn't too bad either.

Cost prohibitive and I don't own the current compressor the fire company does. Remember this is why I dive ID and not manifolded - I am constrained by the fire company rules on filling - I must use the blast containment for safety purposes.

So I have taken this Grade E air to 124 feet - no ill effects and I have an analyzer for both CO and O2 now. All readings are as expected for Grade E air which is clean despite what others may say and since I have been diving it for several years now - my observation is this is acceptable for me.

After I read the Oxygen Hackers guide I hope I can speak with more knowledgeable on the subject and fill in the gaps of my current understanding.

*** added ****
Currently I don't see the need to go above 40% for my needs - so I don't see the benefit of OCA... And for under 40% you do not need Oxygen clean...

 

[tbone1004]

Cost prohibitive and I don't own the current compressor the fire company does. Remember this is why I dive ID and not manifolded - I am constrained by the fire company rules on filling - I must use the blast containment for safety purposes.

So I have taken this Grade E air to 124 feet - no ill effects and I have an analyzer for both CO and O2 now. All readings are as expected for Grade E air which is clean despite what others may say and since I have been diving it for several years now - my observation is this is acceptable for me.

After I read the Oxygen Hackers guide I hope I can speak with more knowledgeable on the subject and fill in the gaps of my current understanding.

*** added ****
Currently I don't see the need to go above 40% for my needs - so I don't see the benefit of OCA... And for under 40% you do not need Oxygen clean...

If you are PP blending, it needs to be OCA because you are filling it with Oxygen. It is literally that simple. If you look at the analysis, it may well be OCA even if it just says Grade E, but you have to look

 

[RayfromTX]

I have looked at that site and determined it is still a "risk" using 100% O2 and you are "cross contaminating" the tank using Grade E and O2 - but this maybe easier and more efficient. Oh and the "The Nitrox Stik is available for purchase for $2300 (up to 30 CFM compressors)" pricing is a bit higher than I wanted...

Mixing Stick

I overpaid a bit at 450 dollars. You can build your own for less than half that. Wait until you read up a bit more and read the oxyhacker's guide a couple of times. Mine is rock solid with almost no adjustment from a full tank of O2 down to near empty. I set my regulator on the O2 at 25 psi so below that I have to adjust the flow meter to keep the content right as I drain it on down to less than 10 psi.

IMG_1746

• RayfromTX
• Aug 17, 2017

 

[Basking Ridge Diver]

Wait until you read up a bit more and read the oxyhacker's guide a couple of times. Mine is rock solid with almost no adjustment from a full tank of O2 down to near empty.

I got it today and I will read it a few times before attempting anything. But if I may ask what size O2 bottle do you use and how many fills do you get?
Thanks

 

[RayfromTX]

My tank of 219 cu ft. of o2 will make about 1,500 cu ft of 32%

 

[Basking Ridge Diver]

check the report on your scba compressor, it may well be OCA if there is no oil present *there isn't on the SCBA compressor that I use

It is not motor oil but special oil used for SCBA compressors. It is an AirPower International compressor with an air cleaner...

For my purposes I am going to treat it as OCA / Grade E for now.

Do you use Industrial O2 or Medical O2?

Thanks

 

[tbone1004]

It is not motor oil but special oil used for SCBA compressors. It is an AirPower International compressor with an air cleaner...

For my purposes I am going to treat it as OCA / Grade E for now.

Do you use Industrial O2 or Medical O2?

Thanks

the special oil is still oil and is still combustible in a high O2 environment. The air cleaner doesn't really matter, it's the filter stacks at the end of it.

I have an O2 generator that works similar to a membrane system, but if I was purchasing for me, I would use industrial O2

 

[Basking Ridge Diver]

the special oil is still oil and is still combustible in a high O2 environment. The air cleaner doesn't really matter, it's the filter stacks at the end of it.

I guess the kicker is - I am using the cascade system (banks) to top off with air once the O2 is in the - not the compressor - the compressor is giving me the 3 banks of 6000 psi in 2 bottles each which as cooled down and is 0 PPM CO2 or "dirty" I have been checking my previous fills.

If I understand this correctly - the banked air which is 6000 PSI will push into my scuba tank which is give or take about 900 PSI and I will fill to 3000 PSI... Again if my understanding is correct - an O2 clean scuba tank and 1st stage should receive this without issue... Unless I am completely missing the point. I talked with John at NESS and he also thought this would work...

Thanks
As I get closer to my first mix - I realize that the voodoo black magic makes me a bit nervous...
And yes there is a filter stack - what I do not know is how it really works to tell you if it makes it OCA...

 

[RayfromTX]

You really should test your air.
Compressed Air Testing - Trace Analytics

 

[RayfromTX]

I guess the kicker is - I am using the cascade system (banks) to top off with air once the O2 is in the - not the compressor - the compressor is giving me the 3 banks of 6000 psi in 2 bottles each which as cooled down and is 0 PPM CO2 or "dirty" I have been checking my previous fills.

What does this mean. Your compressor is not providing air at 0 ppm CO2. There must be a typo.