Small compressors...?

[Lt.Warner]

pescador775
I will respectfully disagree with you. I have been working in the fire service for over 20 years. And I have been drawing the air samples on our compressors for many of those years. Our air will pass most of the time. But there have been times that the test were less than desirable. And yes our compressors were manufactured by a big company like Bauer. Our air is tested of oil particulate, 02 content, and moisture. All I’m saying is if you are planning on owning a compressor for breathing air you should factor in the cost of the test. If it’s man made it can and will fail no matter who mad it. One unit failure that comes to mind. This unit ran great from listen to it you could not tell anything was wrong, however unbeknown to us oil was getting in to our breathing air. This unit had to be serviced by the manufactures rep.

 

[pescador775]

Diester oils in the air supply are easy to identify. Run this test: disconnect the final filter from your compressor and fill the scuba tank directly from the condensator. Without the charcoal filter the oil vapor and gaseous odor will be easy to detect----no test kit necessary other than the human nose. However deficient compared to most animals, the ability to detect minute gaseous contaminants is impressive. It is said that carbon monoxide is odorless. Technically, that is true but carbon monoxide is rarely present without an accompanying contaminant, which does have odor. If the final filter has a triplex type cartridge, and trace CO is getting through, it means that the filter is wet and odors will pass through as well. As far as vapors (different from gas), if any are present the vapor will collect on the wall inside the scuba tank and will have little impact on the air which is breathed; except for the slight odor which may evolve, and this can be detected. If the compressor operator suspects something is amiss he can hold a white cloth over the air stream. If the cloth shows any discolor then an inspection of the equipment should be begun. A big outfit which has insurance and customer relation issues should have the air checked, and hang up a big sign with bold letters. blah, blah. I can understand that. However, if a diver is so bold as to own and operate his own air compressor he should have the minimum technical knowledge to avoid or prevent air quality problems in the first place. Those are facts. My personal opinion is that Americans have been over sensitized to safety issues. This began with Ralph Nader and was picked up by the insurance industry which continues to lobby Congress for all sorts of expensive safety devices, expensive to the consumer but which saves the industry a few bucks. There is a questionable cost/benefit ratio to much of this, to the divers who are loaded up with expensive, bulky stuff of questionable utility and safety. Some things, like hydro testing, make sense. However, yearly regulator inspections or quarterly compressor certs don't. Like yearly "physicals", which were a gimmick invented over 50 years ago, to improve the profit picture for physicians.

 

[pescador775]

Below is a link which makes the case for compressor air quality testing. However, the case is weak. As you will see, an air quality lab was unable to detect a reportedly high level of contaminent. A second lab was selected for additional testing and, as a result, it was claimed that the air from the suspect compressor was tainted with toluene, a gaseous hydrocarbon which ordinarily carries a strong odor (think huffing). What happened to the odor part of this gas I haven't a clue. It was not mentioned in this paper. No diver should use a tank with funny air. Maybe somebody here has info. This incident appears to be the exception which proves the rule, eg, a poorly maintained compressor can produce contaminants and some labs produce questionable results. However, the report below goes on to say that under some conditions the quality of air from a compressor can vary with the time of day and from day to day causing one to wonder if a particular air quality evaluation is useful in general. This article is technical in nature. It should be read and understood by serious compressor operator/owners. However, I view some of its content as speculative and even alarmist. Malfunctions of condensators and chemical filters do occur. Usually, the first indication is water in the SCUBA tank and does not present as a case of the whoozies.

http://www.neptunoworld.com/articles/toluene.html

 

[oxyhacker]

I got to agree with el pescatoradore on this one. An air test only shows the quality of the air at the moment the test sample was taken. But malfunctions, on a
small compressor where the filter cartridge life may be as little as 5 to 18 tankfuls, tend to be transient by nature and it would be just pure luck if one is caught by one, or four, tests. The compressor may have cooked off some carbon last week, making CO-laden air, and may again next week, but if it didn't do it just when the sample was taken, the test won't show it. Or the filtr may have been saturated, and the compressor outputting really lousy air last two weeks ago, then you replaced the filter this week before you took the sample, and the sample will say everything is fine. So at best, given some luck in timing, an air test may alert you to a problem, but at worst it will only give a false sense of security - after all, on a daily basis, a 4 times year check will only have a 1 in 91 chance of finding a transient problem.

However that 4X testing will cost about $500 a year. Not an unreasonable amount of money for a commercial operation, but a lot for an individual owner. So my feeling is most individual compressor owners will do better to be careful about draining their separators, perform regularly some of the DIY air tests pesky and I have mentioned here many times (such as sniff checks, handkerchief tests, and monitoring the color/amount or condenseate), consider fitting a moisture detector and maybe a CO monitor - and most of all, change the filter cartridges more often! Or put the $500 towards another stack.

The situation is different for commercial installations. Their larger filters, which may be good for hundreds and hundreds of tankfuls make output quality a less volitile, and given enough tests over long enough, a pattern will emerge. And anyhow the customers will (or ought to) demand it, imperfect as it is, as a lot better than nothing.

BTW, what was the problem you mention, where oil was getting in your air?

pescador775
I will respectfully disagree with you. I have been working in the fire service for over 20 years. And I have been drawing the air samples on our compressors for many of those years. Our air will pass most of the time. But there have been times that the test were less than desirable. And yes our compressors were manufactured by a big company like Bauer. Our air is tested of oil particulate, 02 content, and moisture. All I’m saying is if you are planning on owning a compressor for breathing air you should factor in the cost of the test. If it’s man made it can and will fail no matter who mad it. One unit failure that comes to mind. This unit ran great from listen to it you could not tell anything was wrong, however unbeknown to us oil was getting in to our breathing air. This unit had to be serviced by the manufactures rep.

 

[pescador775]

As usual, your logic is fine tuned. It's too bad that we lost "Genesis" to the peckish gnomes of Scubaboard. He was some kind of genius and I could use another smart guy on the board to keep me straight.

and:

BTW, what was the problem you mention, where oil was getting in your air?

You said it. I was chomping to ask but......the tech is the one to talk to.

Il Commendatore, er Pescadoratore, er, I mean Pesky.

 

[Lt.Warner]

Sorry for the late reply. I just got busy and forgot to check this thread.
pescador775 I do not consider my self "Genesis". I, like you, am simply sharing my opinion. And I hope that we can agree to disagree. I for one feel the need to have air test ran on a quarterly basis. If you do not, I don’t think the compressor police will even care..Lol

I do not know what the problem was that caused the oil to invade the cascade system. We took the sample sent it to the lab. They contacted us and informed us with the problem. We them called the manufacture. They brought a loner unit and took ours to repair the problem. I do not know just what the problem was. We have since sold the unit and all service records followed.

 

[WVMike]

Bruce, it was in October during DEMA, I accept the apology (even though my feelings were hurt ). I will call and take you up on the offer and won't tell.

3200cf at 80 sounds like 40 hours, I had less than 20 and the filter was soaked. Any Ideas as to what could have gone wrong?

I am going to follow the advice on this thread and install a back pressure valve and moisture detector and keep a close eye on it. Any other things I need to look for?

Mike

Mike, look on your compressor. My mobile number is below the name plate and serial number. You can call anytime with questions. Lawrence Factor says that filter is good for 3200 Cu. Ft at 80*


I am not sure when you called that I did not return the phone call, maybe when we were at DEMA? October has been absolutly crazy here with the DEMA show, ALKIN visit and a training class for our dealers. Still if I did not return your phone call I publicly apologize. Bruce

 

[oxyhacker]

Can't find it in writing, but pretty sure that while L-F rates their filters cartridges based on an inlet temperature of 80 degrees that refers to the FILTER STACK inlet temperature, not the compressor inlet/ambient temperature. Air typically outputs the final condensor coils at 15-20 degrees higher than ambient. So on a real 80 degree F day, the inlet temperature for the media stack could be as high as 100 F.

Higher temperature greatly increase air's ability to hold moisture, so cartridge life goes down quickly as temperature goes up. Most compressor and filter suppliers provide filter life charts to help calculate this, but some sources state that a 20 F degree rise in temperature will roughly halve filter life. This is considerably more than "a little"! So given some warmish weather it is entirely possible that you could have wiped out a filter in half the 40 hours you expected. The lack of a backpressure valve is a wild card that makes it even harder to predict.

3200cf at 80 sounds like 40 hours, I had less than 20 and the filter was soaked. Any Ideas as to what could have gone wrong?

 

[WVMike]

This time frame was in the middle of the summer, and it was a hot one. Easily in 90s ambient. Another lesson learned. "Must Air Condition Compressor Building". Thanks for the help. I have been gathering parts to build a blender, via your plans, and want to work out these problems before I start pumping O2 through the compressor.

Higher temperature greatly increase air's ability to hold moisture, so cartridge life goes down quickly as temperature goes up. Most compressor and filter suppliers provide filter life charts to help calculate this, but some sources state that a 20 F degree rise in temperature will roughly halve filter life. This is considerably more than "a little"! So given some warmish weather it is entirely possible that you could have wiped out a filter in half the 40 hours you expected. The lack of a backpressure valve is a wild card that makes it even harder to predict.

 

[Eris Lucan7*]

I own a Coltri MCH6 electro edition;one time a year i put the waterhighpresure cleaner

in the Presure as Carbonefilter Cylinder and Blow te dirt out with Air.Thats My warenty

Its a good Compressor i dont need him over 20 times a year at all so a bigger aint no

good to me.(That air tec oil is damn hard to get anywhere around only oder it help i hate that). 7*