Use of O2 clean tanks in remote areas...

[diverbrian]

I can't win here.

A bit of background, my LDS carries pre-mixed EAN36 and will use that PP a blend below that if desired. Many of the charters and dive shops up here have Nitrox but use the PP method to make it so I finally broke down and had my tanks O2 cleaned so that I could have Nitrox when I travel. About the only divers at our LDS that go to this time and expense are the techies for the reason that our shop doesn't need the tanks to be O2 clean to fill them with nitrox.

This worked great until last weekend. When it came time to get air fills, I couldn't even risk getting an air fill where I was diving as the dive operators up there aren't using Grade E air to my knowledge. Thankfully, I had brought two single 120's for just such an emergency, but I am getting frustrated here. I would have preferred my doubles on the second day.

I want to go dive North of there and the situation is just as bad. It was suggested to me to get my own filter to take with me on the road to ensure that their air doesn't violate the O2 clean rating on my tanks. Is this a doable option or do I have to load my already overpacked vehicle with more tanks just to dive for more than two days up there. I am sure other people have run into these issues? If the filter option is possible, how do I acquire one and how much can I expect to pay? Ideas?

 

[Boogie711]

They're not cheap. There are a few threads over on Deco Stop.

 

[Ontario Diver]

They're not cheap. There are a few threads over on Deco Stop.

They are not cheap, nor are they user friendly, nor are they small.

You would need more than just a single filter. You would need a water extractor as well.

For the money, you could get lots and lots of O2 cleanings done instead of buying a filter system. Or you could buy some blue slime and learn to O2 clean yourself. It ain't hard.

 

[oharag]

Could someone clarify the issue with filling O2 clean tanks with regular air? I'm new to diving. I've just purchased tanks recently, and I'm going to get them O2 cleaned for partial blending Nitrox (I am Nitrox certified). Isn't regular air the same as Nitrox? It's just at EAN21. Is it the case when you go with partial blending of Nitrox you always have to go this route?

Thanks
oharag

 

[MikeFerrara]

I just clean my tanks periodically and if a place is pumping air that isn't clean enough to go in my tanks I don't want to breath it anyway.

As for hyper-filters, check out Global. They sell a portable one already set up with everything you need for around $1500. You could probably get the part cheaper and throw it together yourself it will see what you need.

 

[salty]

Know the diffrences and standards for E and J air. Ask to see the shops lates air report and see how close it is the E standards. A lot of shops have systems that produce E air but if they dont do Nitrox they wont ask for the elavated rating.

 

[chrisch]

They are not cheap, nor are they user friendly, nor are they small.

You would need more than just a single filter. You would need a water extractor as well.

For the money, you could get lots and lots of O2 cleanings done instead of buying a filter system. Or you could buy some blue slime and learn to O2 clean yourself. It ain't hard.

I sort of agree with the latter half of this but not the first part. Why do you need a water filter? A secondary filter to take the hydrocarbons out is all that is needed. Our club had one and it was about 2inch diameter by a couple of feet long. I regret I do not know the price, but I suspect not terribly expensive.

These filters use charcoal and the problem with them is the constant pressurisation and depressurisation that causes them to degrade.

Scuba air should be water free and no recognised outlet should pump air with water in it.

You need to take the OIL out for pure O2...

Chris

 

[Ontario Diver]

I sort of agree with the latter half of this but not the first part. Why do you need a water filter? A secondary filter to take the hydrocarbons out is all that is needed. Our club had one and it was about 2inch diameter by a couple of feet long. I regret I do not know the price, but I suspect not terribly expensive.

These filters use charcoal and the problem with them is the constant pressurisation and depressurisation that causes them to degrade.

Scuba air should be water free and no recognised outlet should pump air with water in it.

You need to take the OIL out for pure O2...

Chris

The water extractor is required to keep the filter dry. Without it, the filter life is significantly reduced. These filters use more than just charcoal. They have several components to them that remove hydrocarbons, CO, and other things. I can't remember the name but the stuff that remove CO is especially bothered by humidity.

For Nitrox compatable air ( Grade E ), there is more to be removed than just hydrocarbons. If there is oil in your air - your compressor's piston rings are shot.

 

[chrisch]

Ok I have found the product. I am very sorry but I cannot find a North American supplier so the link is for the UK

http://www.div1ng.com/asp/product.asp?product=316

Scuba air should not have CO or water in it. Period. If it has CO its not fit to breathe. Water rusts the tank. You need to remove hydrocarbons to reduce oil contamination to keep the tanks O2 clean. Water and CO will not burn and cannot therefore invalidate the O2 clean sticker.

The price is UKP 72 plus postage. I think thats a little under US$200.

I am sure similar products must be available in the US & Canada. I doubt though if the brand Beaver is as well known there!! (Yes we know what it is this side of the pond too..)

Best
Chris
IANTD Gas Blender and O2 Service Technician

 

[pescador775]

Diverbrian,
That is actually a difficult question, not because there are no solutions but because the question elicits dialogue based on misinformation. That is disturbing because there are so many 'blenders' and 'nitrox' divers who are tripping over this one.

Do NOT buy the 'personal' air filter. That is not suitable.

Probably, every dive shop in the US produces grade E or better. That is because very little technology is needed to achieve that level of air purity. However, shops that routinely jam nitrox through the method of partial pressure mixing are obligated to filter the compressor air to grade J by means of something called a hyper filter. They do this extra, expensive step to avoid liability and because of the rather strident advice and information they get from certain organizations. These organizations get their info from government agencies and the US Navy to whom expense is a taxpayer problem. That is, they can specify zero, zero contaminant option without fear of the cost or practicality common to the civilian community.

In fact, grade E air is good enough for partial pressure mixing. I know this because it is done frequently without problem. The caveat is that the tank must be cleaned more frequently. I can't suggest how often but perhaps once every 100 fills would be prudent.

There are two contaminants that need to be considered. The obvious is oil vapor which can, over several years, produce a microscopic coating on the tank walls. One method of checking for this is ultraviolet (black) light inspection. The other contaminant is particles of carbon and dacron which come from the filtration system itself. This can only be stopped by a micronic filter made of some hard material such as stainless steel or ceramic. I could advise you how to build such a filter over private mail but it appears to me that any filter (no mechanical separator), just a filter, which contains a triplex type cartridge, would be sufficient. Considering that the air coming from a grade E compressor (almost all of them meet tis std) would be filtered again by a triplex cartridge, there should be no remaining contaminant at all, or at least not measureable. Technically, this is not air polishing but so what? The available cartridges almost all contain a micronic filter and plenty of chemicals to scrub oil, water and odor. That micronic filter disk or cylinder is the important thing because charcoal dust is the real bad stuff to watch out for.

If you are really concerned about air purity that is the way to go and should be cheaper than buying one of the overpriced hyper filters.

I am not very knowledgable about the market for such devices since I would just build my own so maybe others will locate a source for a reasonably priced inline filter. However, remember this, the device must contain dessicant, charcoal and a micronic filter. A CO chemical is unnecessary since dive shop compressors do not produce carbon monoxide. You might want to skip any located in a known pollution zone however.