Some question about Steel tanks

[jean yves]

1.Is it most of the steel tanks get rust inside?All of my steel tanks get rusted inside,due to the compressor can't have 100%dry air.
2.Does you all put oil(edible)inside the tanks?Over here,when I send my tanks for inspection,they put some oil inside it so won't get rust easily.
3.My poseidon compressor(Don't really know what is the modal-about 7 years old)have one seporator and 2 purification chamber.Deliver about 150L/min.Manual drain system,drain every 10 min.I notice that the air I get was not 100% dry!Inside the purification chamber have one filter(change every 50 hrs) which take out the smell,moisture.How to get 100% dry air?
Thanks!

yves

 

[Whitelightnin]

If you are serious, you need to understand that putting oil OF ANY KIND in your tank is DEADLY. You will breath some into your lungs & it will cause any of several lung diseases. NO OIL is safe to breath. Not food grade, not peanut oil, not coconut oil.

There is a chemical that we use when we hydro tanks to help keep them from rusting. But it is very diluted and even then, we have to give the tank a quick rinse with plain water to remove most of the diluted stuff. Moving, dry air is what you should use to dry your tank.

Flash rust is not cause for concern. All steel tanks will have some. Don't worry about it.

James

 

[jean yves]

If you are serious, you need to understand that putting oil OF ANY KIND in your tank is DEADLY. You will breath some into your lungs & it will cause any of several lung diseases. NO OIL is safe to breath. Not food grade, not peanut oil, not coconut oil.

There is a chemical that we use when we hydro tanks to help keep them from rusting. But it is very diluted and even then, we have to give the tank a quick rinse with plain water to remove most of the diluted stuff. Moving, dry air is what you should use to dry your tank.

Flash rust is not cause for concern. All steel tanks will have some. Don't worry about it.

James

Ok,Nitrox aside.
Just found out from the Tanks inspection company.The oil they put is 'Parafine'.(Hope I not misspelled it).Can get it from the pharmacy here.After the tanks finish inspect,they put it under the sun to hot it up and pour half cup of the oil inside the tanks,so it will absorb the oil better.They put this oil is to prevent the tanks from getting rusted fast and it is also a 'French regulation'.So it is a must to do it for steel tanks even at France.So may be it is difference in the USA.

 

[jean yves]

Off course the tanks they put oil in it is not for nitrox use.
What I want to know is 'Is it all the steel tanks get rusted inside?' because I read some tread and found out that some of your steel tanks are clean inside but not mine.And I'm looking a way to have my tanks from getting rusted and to have my compressor for a 100% moisture free fill.That's what I want to find out.Unfortuntely,till now my question still there.And Why the French goverment set out this regulation for all the steel tanks to put oil-'parafine' inside?I'm sure the goverment won't set out this rule if there is no advantages.And why in the USA you all no need to put oil inside the tanks?
I found out this board was a good place for me to learn and not for... and there is still 'a lot of helpful' diver here that I know.
If anyone feel that my post was to stir up some problem or let someone feel upset,then I apologise about this.

*It is not only now they out oil in the tanks,but they already have this regulation many years already.Me,myself already use this kind of tanks for many years and also those tourist from around the world who dive here and use the tanks here.

 

[aquaoren]

Off course the tanks they put oil in it is not for nitrox use.
What I want to know is 'Is it all the steel tanks get rusted inside?' because I read some tread and found out that some of your steel tanks are clean inside but not mine.And I'm looking a way to have my tanks from getting rusted and to have my compressor for a 100% moisture free fill.That's what I want to find out.Unfortuntely,till now my question still there.And Why the French goverment set out this regulation for all the steel tanks to put oil-'parafine' inside?I'm sure the goverment won't set out this rule if there is no advantages.And why in the USA you all no need to put oil inside the tanks?
I found out this board was a good place for me to learn and not for... and there is still 'a lot of helpful' diver here that I know.
If anyone feel that my post was to stir up some problem or let someone feel upset,then I apologise about this.

*It is not only now they out oil in the tanks,but they already have this regulation many years already.Me,myself already use this kind of tanks for many years and also those tourist from around the world who dive here and use the tanks here.

Faber tanks from Italy have an internal coating from the factory that prevents rusting.

 

[FredT]

Off course the tanks they put oil in it is not for nitrox use.
I found out this board was a good place for me to learn and not for... and there is still 'a lot of helpful' diver here that I know.
If anyone feel that my post was to stir up some problem or let someone feel upset,then I apologise about this.

*It is not only now they out oil in the tanks,but they already have this regulation many years already.Me,myself already use this kind of tanks for many years and also those tourist from around the world who dive here and use the tanks here.

To keep tanks clean and dry increase the either the residence time in the final drying filter or the size of the filter. One of the easy ways to to do this is to put a 130-150 bar crecking pressure valve down stream of the final filter, and put a check valve between the compressor and the first coalescing filter. This maintains the pressure in the filter bank even while not fillng tanks while still allowing the compressor to be unloaded for startup. This technique is called "pressure drying". It also will increase the effective life of your filters by 3X since most of the water is stripped in the coalescer using this method. Since you are getting moisture past the filter you have saturated the dessicant well before the 50 hours have passed.

Parafine is a wax, not an oil. IF it's dispersed in the final boiling rinse water it will lightly seal the surface of the tank. It will however be a real bear to get out if you ever want to clean them for O2 use. This method was used to provide a protective coating on the barrels of black powder firearms before the advent of smokeless powder and works well. Vapor pressure is high enough it shouldn't be aspirated.

Step one is to pressure dry the air. Applying a chemical coating of ANY type inside a SCUBA tank sould be the last resort.


FT

 

[derwoodwithasherwood]

Interesting. I did a bit of a search and "parafine" seems to be a trade name of a chemical made from silk protein based amino acid compound and aqueous polyurethane. It seems to be used for treating fabrics and in skin care products. It also has water absorbent properties. No mention of Scuba tanks though.

There is a very similar word in Dutch -- "paraffine" -- which I think is equivalent to mineral oil or baby oil. Mineral oil is petroleum based, but edible in the sense that it is often used as a laxative. It would reduce rusting but certainly should not be used with oxygen. And in strong enough concentrations, it is a repiratory irritant -- it can cause coughing or shortness of breath. I don't think I would want it inside my Scuba cylinder.

And in English, the word "paraffin" denotes either:

1.) (Canada and the US) a man-made wax used for candles, sealers and lubricants. It can be distilled from petroleum (usually as a byproduct of gasoline production), coal tar or wood tar. It is sometimes used in processed foods like chocolate, jam, ice cream, etc. as a filler or preservative. It's often used to coat fruit as a preservative. It would be an excellent rust preventer and is not an inhilation hazard but certainly should not be used in the presence of oxygen.

2.) (United Kingdom) Kerosene. As in jet fuel, related to diesel fuel. Not something I would want in my Scuba tank.

As far as getting your air "100% dry", I'm not an expert but I don't think that's possible -- or at least, I don't think that's realistic. The air will always contain a tiny bit of moisture. The trick is to reduce it enough so the dew point temperature is so low the moisture will not condense. High pressure and low temperature naturally condense water out of the air. Lowering the pressure defeats the purpose and chilling the air before it gets into the cylinder might be too expensive. So that leaves filters. You only have 2 filters? Maybe you need more or better filters. Have you ever had your air tested to see what the dew point acutally is?

 

[Leadking]

Faber tanks from Italy have an internal coating from the factory that prevents rusting.

It's not a "coating" it a phosphate "treatment"- big difference

 

[SubMariner]

Ok. Now that the personal insults and off topic dross has been cleaned out of this thread, it's now back in this forum.

Play nice, or the thread will be closed/removed from the public view.

Your co-operation in this matter is greatly appreciated.

 

[aquaoren]

It's not a "coating" it a phosphate "treatment"- big difference

Than why wouldn't you explain what the big difference is for all that don't know it?