Bad air originating in tank and not compressor

[DandyDon]

Don't shoot me down guys but you know household CO detectors such as fireangel etc could you use one of those as these detect low PPM and are readily available for £15 - £25. I know you might get a few sideways looks but if you haven't got the funds for a "proper" analyser could this be used (slight air purge out of tank)

Not really sensitive enough in ultra low range. This model at 26 GBP looks appealing and claims to read down to 10 ppm, and would be great for home or hotel room, but we really need accurate readings lower than that. Carbon monoxide alarm - digital 7 year life | FireAngel

If you wanted to try to use one as an affordable "better than nothing" tester, you'd need more info from the manufacturer: how long does it take to react at 10 ppm, how accurate is it in that range, and how sensitive is it to humidity? You could try it in a 2 gallon freezer ziplock, filling the bag partially full from the tank, and watching as the minimum time passes. I did that with the first CO tester I tried, learned that ziplocks with the slider handle are easiest to close well while you're testing from a tank slightly opened, and a bag would usually last me 3 or 4 dives/tests before it starting leakin too fast, but that model gave me too many other problems.

 

[Doc Harry]

Corrosion studies of steel scuba cylinders performed by the University of Rhode Island revealed that severe corrosion could produce elevated levels of CO just from oxidation of the steel.

http://inrhode.uri.edu/search/?sear...Search&searchlimits=&searchorigarg=tcorrosion

 

[grf88]

Corrosion studies of steel scuba cylinders performed by the University of Rhode Island revealed that severe corrosion could produce elevated levels of CO just from oxidation of the steel.

InRhode

Thank you Doc Harry, this one really had me scratching my head. I really did not think that the compressor could be the source in this instance due to the absence of any CO in the other steel tanks.

---------- Post added August 17th, 2014 at 09:02 PM ----------

These recipes may come in handy for a couple of posters to this thread:
Three Crow Recipes

 

[nadwidny]

Corrosion studies of steel scuba cylinders performed by the University of Rhode Island revealed that severe corrosion could produce elevated levels of CO just from oxidation of the steel.

InRhode

Can't seem to read the paper through that link. I know that paper is out there since I've seen it elsewhere a few years ago so I'll see if i can dig it up.

 

[vincent54]

It's been awhile since I've used my chemistry degree, but a paper from 1978 is dated.

Please let me know the chemical reaction to take Iron Oxide to CO.
It takes a lot of energy to break CO2 to CO, and I don't see anything in a rust lined tank producing that much CO. C02 would be the only available Carbon in an air filled tank, with the exception of trace C0. I think it is instrument error or there was contamination from compressor air already present. . It reminds me of the paper on Cold Fusion.

 

[flots am]

. . .

 

[grf88]

Another source of carbon is the steel itself. I don't know what percentage of carbon is used in the steel for scuba tanks but when we a talking parts per million of CO even 0.25% might be significant.

 

[vincent54]

It would have to be available carbon. An oxide layer would be coating the entire inside surface of tank.

 

[Bob DBF]

What would a CO detector do if it tested a tank with very high levels of CO2, and whatever else was happening in the tank? I know some instruments will act weird if used for conditions not included in their design.



Bob
-------------------------------------
Always use the right tool for the job. A hammer is the right tool for any job. Anything can be used as a hammer.

 

[vincent54]

If the sensor is an IR, then it is affected by water and C02 levels.