how to clean a tank for nx40 max by membrane

[milkathecow]

hi everyone,

I have 40 tanks which have been used with "traditional" air, and am investing in a membrane system. I would like to use those tanks for my clients with nitrox and am wondering how i could clean them or if i really need to clean them ?

system used : membrane max 40%o2

I know about the stickers and stuff, but it's the cleaning process and the "oxy-clean" which i'm not totally sure about ?any help would really be appreciated.

thanks a lot,
Olivier

 

[Drew Sailbum]

The answer you'll get depends upon whom you listen to. The PADI answer is that special cleaning is not necessary in your circumstance since the cylinder will never be exposed to greater than 40% oxygen during the fill process. Some other organizations set the threshold much lower.

In general, a cleaning agent is used to remove all traces of hydrocarbons and then a copious amount of water is used to flush out all traces of the cleaning agent. Foam tests and a blacklight can be used to help verify that the cleaning was successful, hydrocarbons are removed, adn that the cleaning agent has been rinsed away.

 

[jimmac]

The answer you'll get depends upon whom you listen to. The PADI answer is that special cleaning is not necessary in your circumstance since the cylinder will never be exposed to greater than 40% oxygen during the fill process. Some other organizations set the threshold much lower.

In general, a cleaning agent is used to remove all traces of hydrocarbons and then a copious amount of water is used to flush out all traces of the cleaning agent. Foam tests and a blacklight can be used to help verify that the cleaning was successful, hydrocarbons are removed, adn that the cleaning agent has been rinsed away.

If you are using Banked nitrox, i.e. the gass will be mixed outside of the tank its self, I would say you would have no problems filling up to 40% o2 nitrox. However if you will be mixing gass in the tank you will be filling the tank with pure 02 at one point. In the later instance you would defienlty want to have 02 cleaned tanks. This requires AT minium refiting the valve with new o2 clean o-rings and oil. The interier of the tank should also be cleaned with special o2 solution and allowed to dry completely.



Visibility is not an issue

 

[milkathecow]

all in the title... membrane system, no banking or partial pressure... so i'll start with the tanks as they are, and when i do the vis. inspection i'll go for the cleanup and oil out.

 

[Scottri]

I've used Simple Green to O2 clean tanks per the Oxygen Hackers book. Worked fine. I used a Simple Green in an Ultra Sonic cleaner for the valve and parts. Worked great and I still have all my fingers and toes.

 

[netmage]

Your going directly from compressor through the membrane directly into the customers tank? Seems like it'd take forever to fill a tank - as with the membrane you go through alot of wasted compressed air to achieve the higher concentration of o2.

The shop I frequent had a membrane system and they fed it into a bank. Cost was prohibative over the long run and put alot of hours on the compressor. Since they had a large number of bank cylinders they switched over to a homemade stick system and now bank 32%.

Either way. Since neither the tank or valve is seeing anything greater than 40% - no special treatment is required....

Point of note though. I have seen new VIP stickers that have two options:
1. Tank cleaned for Nitrox above 40% and partial pressure filling.
2. Tank cleaned for Premixed Nitrox below 40%.

I have no idea what it means to clean for nitrox premixed nitrox below 40%. I imagine it was a way to convine some rogue shop owners who may have given people flak and wanted to charge for o2 cleaning when not necessary...

 

[BEM]

from catalina's website:

Catalina Cylinders SCUBA cylinders, as-manufactured, are not specifically cleaned for oxygen service and therefore are under no circumstances to be charged with breathing air containing oxygen concentrations in excess of 23.5% (ref. CGA pamphlet G-7.1).

Catalina Cylinders SCUBA cylinders, with approved and fitted valves, and other components, can be charged with breathing air containing oxygen concentrations in excess of 23.5% when the following specific actions are undertaken:


When Catalina Cylinders SCUBA cylinders, fitted valves, and other components are cleaned, maintained, and converted by a technician certified by a recognized and endorsed Enriched Air Nitrox Training and Certification Agency, such as *A.N.D.I. according to the agency's cleaning and conversion guidelines to oxygen service and an oxygen compatible state.


When Catalina Cylinders SCUBA cylinders, fitted valves, and other components are maintained as hydrocarbon free and lubricants compatible with oxygen and aluminum are used.


When all high pressure seat materials (i.e. o-rings, friction washers, lubricants, any other components subject to high pressure gas flow, etc.) are replaced with those deemed as being compatible with high pressure oxygen usage.


When Catalina Cylinders SCUBA cylinders, fitted valves, and other components, once converted by a technician certified by *A.N.D.I. to oxygen service, are to be clearly marked to denote oxygen service.
WARNING: FAILURE TO COMPLY WITH THESE DIRECTIVES MAY RESULT IN CATASTROPHIC FAILURE OF THE CYLINDER AND SERIOUS INJURY OR LOSS OF LIFE.

*A.N.D.I. : American Nitrox Divers International ( or any Manufacturer recognized and endorsed Enriched Air Nitrox Training Agency with Oxygen Service Conversion requirements and procedures which parallel at least those currently practiced by A.N.D.I.).

 

[netmage]

Obviously the lawyers have gotten ahold of this one. Luxfer is taking the same approach....

However they have also backed everyone into a catch-22... They also require an Oxygen compatable valve be placed on the cylinder... To my knowledge such a device doesn't exist for scuba use..

http://www.luxfercylinders.com/support/faq/aluminumoxygen.shtml

 

[BEM]

If you have a Luxfer tank manuf as below, its O2 clean from the factory:

8. Question: Are Luxfer scuba cylinders ready for oxygen service when they leave the Luxfer factory?

Answer: New Luxfer scuba cylinders manufactured from January 1, 2000 , until December 31, 2004 , will have been cleaned for oxygen service at the factory and sealed with an oxygen-compatible cap before being shipped. However, starting on January 1, 2005 , Luxfer will provide oxygen-clean scuba cylinders only by special order. Unless specifically ordered “oxygen clean,” all new Luxfer scuba cylinders will be cleaned for gas mixtures containing only up to 23.5% oxygen. (Of course, it will still be possible to have these cylinders cleaned for use with higher concentrations of oxygen by following the DOT-specified procedures cited above.)

 

[padiscubapro]

hi everyone,

I have 40 tanks which have been used with "traditional" air, and am investing in a membrane system. I would like to use those tanks for my clients with nitrox and am wondering how i could clean them or if i really need to clean them ?

system used : membrane max 40%o2

I know about the stickers and stuff, but it's the cleaning process and the "oxy-clean" which i'm not totally sure about ?any help would really be appreciated.

thanks a lot,
Olivier

BTW do yourself a favor use an oil free compressor if you do.. there was another accident recently with a nitrox stik.. It happened in the philippines, they guy was making 34% and the compressor blew up (he said he couldn't understand why he was followig all the "rules" - less than 40% and so on..).. He got lucky he only lost his leg..