Recommendation for Oxygen Meter for Gas Purge.

[iam42]

Hi Guys,

I need to purchase an Oxygen meter for an upcoming job we are doing. I need to be able to measure the oxygen content for a super duplex job that will be purged with Argon and Nitrogen.

Does anyone have any recommendations for a meter that will do the job and as I have never done this before does anyone have any advice or tips for getting the most accurate measurements?

Thanks

 

[EdStainless]

there are two types of Oxygen meters.
One uses fuel cells, basically a salt water battery and the voltage generated is proportional to the oxygen content.
These are bulky and a bit delicate, but they are very reliable and not terribly expensive.
The other type uses a heated ceramic sensor.
These are very robust but more expensive.
Reach out to specialty gas suppliers and see what you can lease.

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P.E. Metallurgy, Plymouth Tube

 

[iam42]

Thanks Ed,

We will probably purchase one as we seem to have a lot of SDSS work coming up.

 

[EdStainless]

Look for a system, packaged with flow meter and sample pump all in one box.
I haven't bought one in 20 years so I am not sure what is out there.

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P.E. Metallurgy, Plymouth Tube

 

[racookpe1978]

Surprised your weld spec ? calls for a nitrogen purge. Most often, pure Argon is expected for welding without back-gouging/backgrinding when a EB ring (consumable insert) or backing ring can't be used Or is the N2 purge for a operating case to eliminate oxygen during ops?

 

The folks at Huntingdon can help with all your purging needs.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[EdStainless]

Since they are welding duplex they are using Ar + 2-5% Nitrogen for backing gas

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P.E. Metallurgy, Plymouth Tube

 

Since they are welding duplex they are using Ar + 2-5% Nitrogen for backing gas

If it is the original 2205 (UNS S31803), then yes.
The newer version, UNS S32205, has enhanced minimum N content (and one or two other tweaks) that make N addition to the purge gas unnecessary (although as always YMMV).
All 2205 duplex I have encountered in the past few years has been dual certified to both, since the compositions fully overlap. However with existing plant you may not be certain and its probably best to assume it is S31803.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[EdStainless]

We add N to backing gas for any N modified alloy, duplex, superaustenitic, 304LN, or 200 series.
It does no harm.

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P.E. Metallurgy, Plymouth Tube

 

[iam42]

Thanks for all the help guys, I have decided to go ahead and purchase a meter from Huntingdon Fusion