Which compressor to buy?

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David P

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I am setting up a shop for my business that I can no longer work out of garage. Among other sources of income I am setting up a hydro shop and currently rebuild regulators for a LDS but currently run the tests off of a set of doubles and extra single tank I keep filled up. This is a pain in the butt and because Im looking to expand my businesses I am looking at buying a compressor. I am not planning on becoming a major filling station for my area but I do hope to be the only shop around that offers tri mix and fill O2. With those tidbits I am thinking I need to go with a RIX oiless compressor, but I am no expert. I want a good compressor that is reliable. Bang for the buck would be great but I would rather spend a bit more money now and spend less money and time later.

A couple of months ago I spoke with someone from RIX and supposedly I only need drier cartridges for their compressor where RIX there is a set schedule for repair, at this many hours you rebuild this with this kit for this much money and the after this many more hours you rebuild that with that other kit for that much more money...ect. How do the RIX compressors compare to other compressors in service life? Any input, advise, or leads.... would be greatly appreciated.
 
RIX states that their SA6 compessor is not suitable for NITROX or oxygen. However, some use the RIX for general purposes including pumping NITROX. Pumping oxygen can best be done with a Haskel AGT 15/30 booster cleaned for pure O2. Using a RIX to compress O2 could cause a fire but pumping O2 with an oil lubed compressor could cause an explosion. The RIX can be maintenance intensive and may have a tendency to heat up when pumping dry gases such as argon and oxygen/air mixes. Pumping air, the RIX can be expected to run about 300-400 hours between change outs of some parts like the third stage piston. RIX says that this planned maintenance is easy to do. The RIX is well known for pumping water. Extra filtration and a back pressure valve would be needed.

Oil lubed compressors like the Bauer can run up to 2 thousand hours before any heavy maintenance but of course oil changes and filter maintenance will be needed regularly as specified by the mfgr. This type of compressor can pump NITROX 36 with no problems that I am aware of. I recommend a PAO oil, H1 grade (NUVAIR 455). I suggest that you purchase an oil lubed compressor and construct or purchase a NITROX stick and avoid PP filling of oxygen if possible. If oxygen is to be handled then transfilling oxygen for rescue bottles, stage bottles , etc should be done by decanting or with a booster pump which has been cleaned for this purpose. Topping off oxygen with air may require extra filtration for the oil lubed compressor. This is to avoid any possible oil film from accumulating in an oxygen cleaned and certified tank. Note that it would take a while for this to happen and the possibility of a hazard is relatively small when using a good system but there could be liability concerns unless your system is set up to pump "modified grade E" air which is generally considered to produce an acceptably low level of hydrocarbons. However, when using the continuous blending method, the concern for oxygen clean conditions in the Scuba tank goes away.
 
I agree with pescador775. While the Rix is a fine machine, it should not be used for pumping oxygen. Masterline makes a very fine booster specifically designed for pumping oxygen.

However, I vote for the nitrox membrane system as well. ColtriSub has a very nice 10 CFM system that has the capabilities of pumping either straight air or 24%-40% Nitrox at the flip of a switch. Unfortunately it is spendy ... $19500!

The smallest (and cheapest) system that I have seen as a ready made package is only $6895 but can only run up to one hour and then needs to be shut down for an hour.

Just my $.02
 
The Masterline oxygen booster is a slick little machine. It is less hassle than the Haskel booster but has lower output for the money, primarily because Haskels are readily available on the surplus market
http://www.masterlineinc.com/products/booster.htm.

I see used Bauer compressors on EBay and on govliquidation. Same with LP compressors needed to charge the membrane system. Seems to me that a used Bauer Mariner or Capitano, and Nuvair membrane system could be assembled for about 10K. There might still be a need to stock pure oxygen, however.
 
There have been rumors of compressor scams on ebay (like with just about everything else, esp. rebreathers). Shop wisely, possibly picking up your mechandise in person.

Rix does make machines specifically for pumping O2, but they are extraordinarily expensive. A masterline or haskel booster will be more efficient $$ for moderate O2 volumes.

Do you have a mixing cert? You'll probably need one to allow your insurance to cover this new biz line.
 
How did this thread get onto Haskels and membrane separators so quickly? As I read it, he is looking for a good entry-level system that he wouldn't outgrow too quickly. I'd go for a decent used continuous-duty compressor (Bauer Capitano or better), a continuous mixer and a reasonably sized O3 and He cascade. Then if the gas biz developed, add a Haskel, and then maybe a membrane. I wouldn't bother with a Rix. Clever gadgets, but not really the right rig for a shop. There are some great deals in used medium capacity fill systems now, what with all the fire departments buying new ones with homeland security grants. The $7000 system Ray mentions uses, I think, a MCH-6 Coltri block which just isn't up to commercial service.
 
He said he wants to fill O2. Since he's also getting into trimix, that O2 is going to be at 3000 psi, 30 or 40cf at a time.

I wouldn't bother with a Rix or a Coltri built compressor either.
 
RJACK, I have tried to contact EBay about the scams but not having any luck. The ads are numerous and blatant, two or three compressor auctions at any given time are obvious scams. At first, they were "private" auctions with identities obtained by phishing. Now, one sees auctions with new ID's and no feedback. The descriptions are copied from previous, legitimate auctions.
 
Yeah, David says he will front the money for a good system. Pumping oxygen without a booster won't make any friends among the rebreather set. There is such a thing as getting ahead of oneself so maybe hacker has a point, too. A cascade can satisfy some of the trade but it will be difficult to keep decent head pressures if the cascade is being run down by nitrox fills. Still, if a blending stik is rigged up, then the storage bottles will give more bang for the buck and should be satisfactory for added duty filling hang bottles. I agree, membranes are a bit advanced for a start up.
 
pescador775:
RJACK, I have tried to contact EBay about the scams but not having any luck. The ads are numerous and blatant, two or three compressor auctions at any given time are obvious scams. At first, they were "private" auctions with identities obtained by phishing. Now, one sees auctions with new ID's and no feedback. The descriptions are copied from previous, legitimate auctions.

I have seen them popping up from time to time, buyer beware. Esp. if they ask about using an escrow service and all the other warning flags. If you're dropping this much money on an item, best to be able to check it out in person anyway.
 
https://www.shearwater.com/products/teric/

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