re-using disposable compressor filter particles/parts???

[needmynitrogenfix]

hello,
i would like anyone who knows about compressors to reply and tell me what they know about this. i have worked at several dive shops and all have used the small bauer compressors which each fill two tanks at a time and use blue plastic disposable filters about one foot long and two inches diameter. most shops replaced the filters after the recommended amout of air passage but two did not: (1) east marine dive center(langkawi and perhentians) - they dump out both the black particles and white particles onto a tray(now all mixed up) and put them in the sun to dry. they would wash and put out to dry the other parts and felt pads inside the filter. then they would reassemble the filters, but instead of keeping black particles seperate from white and in the correct chambers of the filter, they would fill each section with a mix of the already mixed up black and white particles (which have been used...many times)! (2) i wont name the shop - would do the same as above, but throw out the particles and replace with new particles(from canisters they purchased) , placing white and black in the correct sections of the filter where each should go. just curious to know if (1) and/or (2) is acceptable? im guessing (1) is not and (2) might be ok? thanks for your input!

 

[clownfishsydney]

While some people can and do repack the Bauer filters, you would never do what the first one did. You can theoretically dry the white ones (Molecular Sieve), I do not think you can reactivate the black ones (carbon) this way. I know that some people when they do repack do it as per 2. This is acceptable, although most will only do it for a few repacks as they said the plastic body started to deteriorate.

I repack my filter but I have a stainless steel repackable filter.

 

[Peter69_56]

Reusable filters are ok on dive compressors, as I have one, however the procedure is to throw ALL the contents; felt pads, activated charcoal (black particles), molecular sieve (white particles) and replace them in the correct order with NEW material. The only things I keep are the metal cylinder and the metal separation plates. All the consumable material is disposed of and NON kept even if it looks somewhat ok.

Anything less than new filters (or new material if refillable cartridges) is NOT acceptable in a commercial dive shop, or if you supply air to other than yourself.

What people do with their own air is their business and if they are stupid enough to be a cheapskate with air filer products to save a few bucks over their life, all I can say is they are a temporary citizen. My personal opinion is that its utter stupidity to think the average user can bleach out and wash out in water, contaminates sufficiently to supply constant and clean breathing air. My life and those of others is worth far more than the cost of the material.

Just goes to show one should test all their gas before use, particularly so in third world dive sites.

 

[NAM001]

As stated above the norm is to replace the chems. It looks like the shop is trying to dry our the chems. first the 2 chems should be a desicant and a carbon filter granules. I have no idea what can they think can be done with charcole settng in the sun as far as rejuvinating them. In regards to the desicant to renue it would take an oven at perhaps 500 f to cook the moisture out of it. I wouldnt get my gas there!!!!! Perhaps someone can elighten me if there is a benifit to this at all.

 

[Camerone]

The actual answer is "it depends," not "throw everything away." Mixing everything and trying to dry it in the sun, however, is right up there with the stupidest ideas I've ever heard. Not knowing or caring who they are, I would personally stay away from those people before they injure someone with that kind of behavior. Drying in the sun is never an effective or correct technique... and you can't tell from "looking" whether the material is okay or not.

If you have an oil free compressor that's working properly, like a Rix, the only major output is water vapor. The "white stuff" is Molecular Sieve 13X, which will primarily adsorb (not absorb... very different process) the water vapor present, drying the air, which makes the following chemicals more effective. With everything working right, you could, in theory, reuse the same chemicals forever, although you'd have to be assured things always were right with the compressor.

If you have an oiled compressor (Bauer, Coltri, etc), it's different, as there are oil particles in that stream as well, and those, too, are adsorbed by the sieve.

You can bake off the water, if it's only water - that is, you have a Rix - an oil free compressor, by heating in an oven (doesn't have to be that high heat.) You then have to cool that material in a fairly dry environment to refresh it. If it's oil + water in the 13x, you might as well consider the 13X "spent" for all practical purposes and just dispose of it.

It's all moot, though. The stuff is cheap enough to just use new.

The second chemical which might be there is hopcalite (omitted sometimes on oil-free units). It's a manganese based catalyst to convert carbon monoxide to carbon dioxide. It also can remove other volatile organic components. It's got to be bone dry to work. If your 13X is spent, your hopcalite is due for replacement, since it's probably saturated. This is a grey-ish material.

The carbon (activated charcoal - the "black stuff") needs to go after all of that. Its job is to remove the volatiles that get through and clean up bad odors/smells. It's not going to take out the CO2, it _will_ catch residual oils if there are any, and it will be trashed by water.

In _theory_ you can regenerate it, too, but you would need an industrial type kiln to reach the temperatures you need to do it. It's also a renewable resource (coconut shells) and dirt cheap, so you replace it.

As far as the rest of the material goes, there's just pads and a spring. I reuse the pads and springs. The pads get cleaned in a long soak in the ultrasonic cleaner with a degreaser to remove any oil trapped in there, rinsed thoroughly, and baked dry. I replace them when they look worn. Their only real job is as a particulate filter (moot with the coalescer, anyway), and to separate out the layers during packing (helps to avoid channeling in the filter). Eminently reusable stuff.

 

[NAM001]

Here is an article that has been around for a while that is exellent in explaining compressors and filtration
Understanding SCUBA Compressors and Filtration

 

[needmynitrogenfix]

thanks for all the answers guys!