View Full Version : OT - testing an O2 concentrator?

09-15-2010, 08:41 PM
There was some recent mention here about oxygen concentrators for use operating small torches and such. As it happened, I was offered one for free the other day so I grabbed it.

The person who gave it to me said they had replace it with a new unit because it seemed to not quite be producing O2 properly. She determined that because when the patient was using it at full flow, it would raise their blood oxygen saturation some, but not quite enough. A new unit at the same flow would bring the blood sats up where they belong, so this was deemed sub-par.

I have not played with this yet, but am wondering if any of you guys have any ideas as to how I could test this to see if it is, indeed, concentrating oxygen. Closed container testing on the cat is out, as we don't have a cat, and my wife won't let me near the kids with it. Any clever thoughts?

09-15-2010, 09:16 PM
Can't help you with the testing, but do know that on the larger capacity flow glass working torches they have to gang 2,3 or 4 together to get enough output for the torches to operate properly. And that is with rebuilt units.

Biggest reason they haven't caught on in the welding field cost of a unit the proper size for a regular torch.

The beaders that use them swear by them.
here is a forum that may have somebody that can be of some hekp (http://www.lampworketc.com/forums/)

09-15-2010, 11:00 PM
The old trick in chemistry class was to stick a glowing wood splint into the oxygen stream. If the oxygen level is high in the gas stream, the splint will burst into flame. Use appropriate care while doing this. . . blah blah blah.


09-16-2010, 12:10 AM
The burning ember test will tell you if the unit is working, but not if it's working as it should. Even with a reference for a comparison, it's going to be subjective...as in "how fast did it burst into flames".

09-16-2010, 01:34 AM
There is a meter they use to test concentrators. The only place I have ever seen one was at a shop where they were servicing these machines.


People say I'm getting crankier as I get older. That's not it. I just find I enjoy annoying people a lot more now. Especially younger people!!!

09-16-2010, 09:49 AM
O2 partial pressure meters are commonly used in technical scuba diving. I'd bet that if you went to a shop that did nitrox or trimix fills when they were slow and offered $5 if they would test your concentrator you would know for sure.

09-16-2010, 01:45 PM
Here is an easy way to test for oxygen content of the output of the O2 concentrator...


Who would have thought that rust could be useful? ;<)


Lew Hartswick
09-16-2010, 02:35 PM
Here is an easy way to test for oxygen content of the output of the O2 concentrator...


Who would have thought that rust could be useful? ;<)

I was going to suggest burning the O2 with H2 and measuring the amount of water produced. :-)

09-16-2010, 05:52 PM
That pdf giving precise instructions seems a bit over complex to me.

The principle's right though. At school, it was to turn some kind of glass beaker upside down over a burning candle. As the candle burns, the oxygen is replaced by carbon dioxide one for one. Now, the CO2 dissolves, sucking the water up. The volume left when the candle goes out is a measure of the O2 that was there.

Of course, the candle goes out well before all the O2 is gone, but still.

Do two identical runs of this, bubbling your concentrate up into the beaker somehow, and you'll get a good indication.

The more you do it, the more accurate you'll get. For example, to really use all the oxygen, and produce no CO2, use magnesium strip instead of a candle.

09-16-2010, 06:55 PM
Hire a personal 3 in 1 gas monitor, the kind you clip onto your lapel that give you a warning when the o2 goes down or theres co above 80 ppm etc, stick it in a clear bag, stick the outgas hose from the concentrator in the bag switch on and read the O2 of the display [thats what i did today anyway]
flow can be checked with a rotameter used for argon [ok i know the compensation bit but its close enough!] three in ones are remarkably accurate and get regular calibrations by law.

09-16-2010, 09:34 PM
Thanks for all of the links and ideas. Excellent stuff.

Yeah, PT, I know this won't run a "real" torch, I'm thinking of it for use with my small Smith "Little Torch" jewelers torch. I already have a seperate acetlyene B tank that I run an air-acetylene torch with at my small-stuff bench. With the concentrator, I avoid having to wheel my big oxy-acet rig over to use the O2 tank when I use the Little Torch.

Not something I really needed, but hey, it was free!!

Thanks again for the input. The collective brain power here never ceases to amaze.