Combined Helium/Oxygen Analysers

nigelh

A post while a 7L bailout is filling with O2 so I'm just sitting listening to the needle valve make little noises to itself....

I have one of the old Abyss TekCheck units and it's getting old and tired (I know how that feels), it needs a couple of new sensors and the battery doesn't seem to stay charged as long as it used to so I'm wondering if it is time for a whole new box.

My wish list is something portable (boatable) that I can plug straight onto the Inspiration feeds as I have them on both counterlung injectors and my stage regulators, is tolerant of a little water in the tubes (I added a trap to the Abyss after having to dry things out once) and has calibration controls so I can feed it 100% He and the 100% O2 and set the readings spot on.

I'd rather not pay a defence budget but I'd rather have a good one than a cheap one as instrumentation is my business and I'd hate to discover I'm dead from breathing a bad mix - just too embarrassing. What do you guys use?

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nigelh

Philippe GERIN

ATOMOX: $550 on sale = £280. here.
Best
Philippe

rjack

That's what I have, although the He fraction cannot be calibrated.

Philippe GERIN

???? Please explain.
Best
Philippe

rjack

It is precalibrated to ambient air, essentially zero helium. There's no knob to adjust. Mine reads about 0.3% just sitting out.

It does not measure helium directly (no helium analyzer does). They all measure the difference in thermal conductivity between a known gas (ambient air) and your unknown gas in your tanks. The difference is presumed to be helium. Having another gas making up any significant fraction in your tanks gas will mislead the sensor. E.g. methane or argon. It will give you a number but it won't be correct.

If it doesn't read 0% or very close to it in ambient air the sensor is bad and needs to be replaced.

Here's their blurb on how it works...
ATOMOX Inc. - HeLIUM ANALYZERS

starfishdiving

I have two of the Analox ATA He-O2 analyzers. I've used them for about 4 years now (one of 'em). Can't complain at all.
They have calibration adjustments for both the O2 and the He.
It measures the He in continuous flow. No need to trap a sample.
Analox is a British company, by the way.
Analox Sensor Technology - Oxygen Analysers and Carbon Dioxide Analysers from the UK
dive safe!

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Randy Williams
Seattle, WA USA

Con***ius say: "Man who say it cannot be done should not bother the man who is doing it."

hoppyinca

Wheatstone Bridge circuit, used in analysis of (gases in) water for nuclear reactors... very reliable; however, I would've thought that they would provide a means for "zeroing" the meter...

hoppyinca

Beanie

me too

but only one and for about two or three years

Don't think you can plug it to an LP hose straight out of the box but I would of though it could be adapted if you wanted, I just analysis all my cylinder before leaving home.

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Beanie
Gallery Admin & Library Assistant.
www.outlawdivers.org.uk
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0871 242 7808

rjack

Nope no adjustment possible, mine reads 0.3% or something like that in ambient air. They claim a ~10 year life. Supposedly if its "off" it needs to be replaced.

For $400 I am real happy.

Decodiver

I used the Analox He/O2 analyser, if you get hold of a suitable sized nipple you can bleed the gas from your manual feed hoses through the analyser with no problem.

Cheers,

Dave Cooper.

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