Which compressor to buy?

[David P]

Ok, I guess Ill put in what I'm planning/hoping first I plan to pump air to a bank for the repair bench, and filling cylinders after hydro. If someone wants nitrox I plan on having a simple stick for upto 40% and having a small bank of that too. For anything over 40% I plan on a small cascade with a booster.

Am I understanding correctly that when yall say RIX cant pump O2 do you mean no enriched air? I thought I would be able to just use a stick and introduce the O2 into the suction line...? Hmm intersting I was under the impression that the main reason to get a RIX is because of the O2 compatability...

 

[Slipstrm]

I would avoid Ebay for an item of this magnitude (compressor), I believe its better to go with a new one now and if you'll excuse the term....Do it right, the first time. Believe me it'll save you money, time and effort.
If you get ripped off on Ebay, there goes a large percentage of your start up capital.
If you buy new, you have a warranty to fall back on as well.

 

[pescador775]

The only RIX which is O2 compatible is a custom model of the SA6 made in England. However, the US made RIX is commonly used to pump NITROX. (NITROX is not O2). RIX doesn't recommend pumping NITROX but I am unsure of the reason. I already said all this before, except the England part. When blending NITROX, the oxygen is fed into the stick, not into the "suction line" of the compressor. That would mess up the whole process and cause a hazard. Purchase a RIX but make sure you also get the $1200 filter set to wring out water. At least, get them to certify the dew point of your unit. It should be -60F. SDDiverdude has been hounding RIX for months and threatened a lawsuit until they agreed to send him a filter for free. His dive club had to tumble about 20 tanks. The RIX does not have an oil sump to lubricate reciprocating parts, tie rods and wrist pins. RIX supplies a special grease for this purpose. These parts have questionable longevity. Many divers use the RIX successfully. However, shops which supply a lot of NITROX generally use oil lubed compressors, for example FILL EXPRESS. The oil lubed compressor is simply more rugged when subjected to continuous use. The big upside that I see is that PP filling can be done with a RIX while reducing any maintenance concerns WRT oil intrusion into an oxygen clean scuba tank. I see no advantage for continuous flow blending. The RIX company do not understand the requirements of divers. Their advertising does not connect well with the facts. Mainly, they were supplying units to the Navy who, I presume, were simply emptying or discarding their aluminum tanks when they filled up with water. Now you know.

 

[David P]

The only RIX which is O2 compatible is a custom model of the SA6 made in England. However, the US made RIX is commonly used to pump NITROX. (NITROX is not O2).

Right! but when people said you cant pump 02 I thought they meant the O2 that is injected into the stick...

RIX doesn't recommend pumping NITROX but I am unsure of the reason.

I think all compressor companies say that as a general CYA

I already said all this before, except the England part. When blending NITROX, the oxygen is fed into the stick, not into the "suction line" of the compressor. That would mess up the whole process and cause a hazard.

Yes I understand this, poor choice of wording on my part.

Purchase a RIX but make sure you also get the $1200 filter set to wring out water.

The salesrep said the same thing

The big upside that I see is that PP filling can be done with a RIX while reducing any maintenance concerns WRT oil intrusion into an oxygen clean scuba tank. I see no advantage for continuous flow blending.

right! thats why I was looking at the RIX... but its starting to sound like it would be better all the way around to use a "normal"(?) oil bath compressor and add some extra filtration on it for when I fill tanks with higher O2 levels.

 

[rjack321]

right! thats why I was looking at the RIX... but its starting to sound like it would be better all the way around to use a "normal"(?) oil bath compressor and add some extra filtration on it for when I fill tanks with higher O2 levels.

For commercial use, yes. A (now defunct) shop up here had 2 Rix units and seemed like at least one of them was continually being worked on.

You will need extra filtration since your tech customers will expect you to not contaminate their O2 clean tanks - even when pumping just air or 32%. This is regardless of whether ordinary grade E air is actually that big of a contaminant source or not.

You really need to get that blending cert.

 

[pescador775]

Rjack is right; David, you are going to need a dose of smelling salts before embarking on your high pressure career. A mixing course seems to be in your future. About compressors, the only "oil bath" compressors are rotary and centrifigal. Recip compressors have wet sumps or dry sump. Correct terms to use for recips would be "splash", "force feed" or "pressure". Some use a combination. For example, the Bauer Capitano uses force feed lubrication for the stages. The small Coltri uses splash lubrication.

 

[cobaltblue]

Funny this thread is going right now. I just finished dealing with Bauer on a compressor that I purchased that got damaged in shipping, (FedEx's fault) Long story short, Buy a Bauer. Bauer is awesome to deal with. They are taking care of me better than I could expect. Helping me with other stuff too! All the compressors are going to pump air, get one from a company that will do what it takes to make you happy. Bauer Rocks!

 

[rjack321]

Glad to hear that all worked out with Bauer.

I have a W31 Alkins, which is nicely built IMO. But the distributor (Airtex) screwed up the manufacturing instructions to lawrence factor and they built a bunch of disposable cartridges upside down. They have not tried to contact purchasers, but will exchange a bogus built one. EDIT: my bad they are now contacting users
http://www.airetex.com/news.html

Alkins/Airtex also has flat out lied in their filter usage tables in the owner's manual. They appear to have used Bauer PO cartridge data but substituted coallescer inlet temp with ambient temp.

The unit I have is well built and quiet - which is important in my neighborhood.

 

[David P]

Rjack is right; David, you are going to need a dose of smelling salts before embarking on your high pressure career. A mixing course seems to be in your future. About compressors, the only "oil bath" compressors are rotary and centrifigal. Recip compressors have wet sumps or dry sump. Correct terms to use for recips would be "splash", "force feed" or "pressure". Some use a combination. For example, the Bauer Capitano uses force feed lubrication for the stages. The small Coltri uses splash lubrication.

I completely agree. I am just now starting to look into the compressors for basic use, but I didn't want to be short sighted and buy a compressor that would only work for a year or two. I want something that will grow with me and my company. That is why I am asking here.

 

[rjack321]

Ingesoll Rand's are built like tanks. But are expensive and at least around here parts aren't easy to find.

I'd go for a ~10 cfm Bauer and invest in a fairly large sized bank.

Do you have 3-phase power available? Just having single phase will limit you max size.