Nitrox Fills

[Scubaguy62]

So are you saying that using method B does not meet the O2 clean standard?

No. Only that my cylinders are O2 clean and that despite my fill station mixes the gases using continuous gas gas blending into a bank cylinder, from which they fill their customers' cylinders, my cylinders are also available for PP filling.

A cylinder does not have to be O2 clean for continuous gas blending method, as there is no 100% oxygen passing through the components. That does not mean that the process does not meet O2 standard.

 

[nwdiver2]

I use a membrane filter and usually produce 40% O2. Why would a tank that had gas from my system then not be used for partial pressure filling? The partial pressure filled tank has nitrogen form a compressor in it once filled. It may have been filled to 40% O2 in fact.

This assumes the air is properly filtered and stored. Of course the storage tank for pp blending is the scuba tank.

Its paranoia and greed stepping in, I have had this argument with several shops that don’t use membrane filtered O2. It’s a my compressor is better than your compressor argument, because the contamination can just as easily be introduced during pp blending.

 

[wedivebc]

No, its not the PPO2 thats the problem its the FO2.

Can you tell me where you got that information?

 

[jeffkruse2000]

Can you tell me where you got that information?

This is in the oxyhacker companion from Airspeed press. It is also stated in many other sources including NOAA. I do not have those publications at hand to quote from right now.

Read the Oxyhacker companion and all your questions will be answered.

If you continuous blend with an oil compressor that doesn't have filtration designed for creating oxygen compatible air then your tank may get contaminated with oil to the point where PP blending with that tank could be hazardous.

You can put pure O2 in a tank that has oil in it if you do it slow enough. On the other hand, you can ignite the cleanest tank that's been cleaned in a clean room if you put the O2 in to fast.

 

[wedivebc]

This is in the oxyhacker companion from Airspeed press. It is also stated in many other sources including NOAA. I do not have those publications at hand to quote from right now.

Read the Oxyhacker companion and all your questions will be answered.

If you continuous blend with an oil compressor that doesn't have filtration designed for creating oxygen compatible air then your tank may get contaminated with oil to the point where PP blending with that tank could be hazardous.

You can put pure O2 in a tank that has oil in it if you do it slow enough. On the other hand, you can ignite the cleanest tank that's been cleaned in a clean room if you put the O2 in to fast.

I have a copy here and I can't find anywhere do you recall what page?

 

[jeffkruse2000]

I have a copy here and I can't find anywhere do you recall what page?

I'll try and find it tonight when I get home.

My CB blender can be found at: http://www.seanet.com/~katrinakruse/
Jeff

 

[wedivebc]

I'll try and find it tonight when I get home.

My CB blender can be found at: http://www.seanet.com/~katrinakruse/
Jeff

Thanks, nice fish tank BTW

 

[padiscubapro]

This is in the oxyhacker companion from Airspeed press. It is also stated in many other sources including NOAA. I do not have those publications at hand to quote from right now.

Read the Oxyhacker companion and all your questions will be answered.

If you continuous blend with an oil compressor that doesn't have filtration designed for creating oxygen compatible air then your tank may get contaminated with oil to the point where PP blending with that tank could be hazardous.

You can put pure O2 in a tank that has oil in it if you do it slow enough. On the other hand, you can ignite the cleanest tank that's been cleaned in a clean room if you put the O2 in to fast.

You obviously havent seen any compressor heads that have had hole blown through them from trying to push oxygen enriched air through them..

Cast iron, and Carbon Steel heads do well, but any compressor that uses aluminimum blocks or heads is at risk. A majority of the compressors used by diveshops use aluminimum heads... RIX and Ingersol Rand do not use aluminimum heads.

 

[jeffkruse2000]

My (older) Rix SA6 has aluminum heads.

Top of Page 10 of the 4th edition oxygen hackers companion. It says 600psi of O2 should be safer than 3000 psi of air IF safety was a result of PO2 only. It is not. Obviously 3000, even 3500psi of air is safe (as far as combustibility goes). Otherwise all those compressors that use oil and fill air to 3500 psi would blow up. In the beginning of the book it always references FO2's not PO2's.
A lot of people continuous blend Nitrox. Unless you have an oil free compressor like the rix your going to expose the Nitrox to the oil in the cylinders of the compressor.

A surge of O2 above 50% might be burning up the heads you mention.

Hope this helps.

 

[wedivebc]

My (older) Rix SA6 has aluminum heads.

Top of Page 10 of the 4th edition oxygen hackers companion. It says 600psi of O2 should be safer than 3000 psi of air IF safety was a result of PO2 only. It is not. Obviously 3000, even 3500psi of air is safe (as far as combustibility goes). Otherwise all those compressors that use oil and fill air to 3500 psi would blow up. In the beginning of the book it always references FO2's not PO2's.
A lot of people continuous blend Nitrox. Unless you have an oil free compressor like the rix your going to expose the Nitrox to the oil in the cylinders of the compressor.

A surge of O2 above 50% might be burning up the heads you mention.

Hope this helps.

What Vance is saying in the book is that PO2 is not the only factor. Although I have never put enriched air through my compressor (bauer oil lubricated) I personally know of 2 compressors damaged by high PO2. Like Padiscubapro stated above, enriched air and oil are very dangerous.
I took a snip from this web page concerning hyperbaric fires involving high pressure air and combustablility.

http://www.fire.org.uk/IFE/ife-agm/peterLSi.htm

The burning rate in air at 2 bars absolute is 1.4 times that at sea level, and it is 2.3 times as fast at 6 bars. A rise of 4% oxygen contents at normal conditions increases the burning rate by 26%, and a further rise to 31% results in 39% increase.