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Hi All
I've been lurking on this list for about a month now but since I've recently
looked
into this I thought I'd share some info. My guess is that the sensor
measures the thermoconductivity of the gas mixture. If you have a gas
mixture of O2, N2 and He, it would seem to be relatively easy to find out
the percentage of He in the mix since the thermoconductivity of the various
gases is as follows ( as taken from the CRC)
Air 60.34 cal/sec
nitrogen 60.34 cal/sec
oxygen 61.58 cal/sec
helium 352.1 cal/sec
Even if the relationship of thermoconductivity to gas mixture is not
strictly linear, any amount of helium in the mixture would raise its
thermoconductivity. Coupled with an
O2 sensor, the actual O2, N2 He mix could be determined. Such meters exist
for industrial applications although one I just recently looked into (the KG
1550 Gas Analyser ) had a price tag of around $5900. Hope this helps.
Eric Nelson
Mike Rodriguez wrote:
> At 01:02 PM 1/24/00 EST, Deep1dave@ao*.co* wrote:
>
> >Did anyone see the new Dive-Rite Helium sensor at DEMA? Any thoughts?
>
> Huh? How in the world would that work? Helium is 100% non-reactive,
> even with fluorine. I can't think of any way to detect it, let alone
> measure its concentration without a chromatograph. Maybe they're
> using some indirect method? Anyone know how this sensor works?
>
> -Mike Rodriguez
> <mikey@ma*.co*>
> Pn(x) = (1/(2^n)n!)[d/dx]^n(x^2 - 1)^n
>
> --
> Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
> Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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Hi All
<p>I've been lurking on this list for about a month now but since I've
recently looked
<br>into this I thought I'd share some info. My guess is that the
sensor measures the thermoconductivity of the gas
mixture. If you have a gas mixture of O2, N2 and He, it would seem
to be relatively easy to find out the percentage of He in the mix since
the thermoconductivity of the various gases is as follows ( as taken from
the CRC)
<br>
Air
60.34 cal/sec
<br>
nitrogen 60.34 cal/sec
<br>
oxygen 61.58 cal/sec
<br>
helium 352.1 cal/sec
<p>Even if the relationship of thermoconductivity to gas mixture is not
strictly linear, any amount of helium in the mixture would raise its
thermoconductivity.
Coupled with an
<br>O2 sensor, the actual O2, N2 He mix could be determined.
Such meters exist for industrial applications although one I just recently
looked into (the <a href="http://www.hitech-inst.co.uk/kath.htm">KG 1550
Gas Analyser</a> ) had a price tag of around $5900. Hope this
helps.
<p>Eric Nelson
<p>Mike Rodriguez wrote:
<blockquote TYPE=CITE>At 01:02 PM 1/24/00 EST, Deep1dave@ao*.co* wrote:
<p>>Did anyone see the new Dive-Rite Helium sensor at DEMA? Any
thoughts?
<p>Huh? How in the world would that work? Helium is 100%
non-reactive,
<br>even with fluorine. I can't think of any way to detect it, let
alone
<br>measure its concentration without a chromatograph. Maybe they're
<br>using some indirect method? Anyone know how this sensor works?
<p>-Mike Rodriguez
<br><mikey@ma*.co*>
<br>Pn(x) = (1/(2^n)n!)[d/dx]^n(x^2 - 1)^n
<p>--
<br>Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
<br>Send subscribe/unsubscribe requests to
`techdiver-request@aquanaut.com'.</blockquote>
</html>
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