ppm of oxygen

Date 11-30-2009 10:48 Edited 11-30-2009 16:44

Correction! Correction!
One ppm of oxygen diluted in another gas, expressed in volume by volume, would be 1 milliliter in one cubic meter. Now, as volume of gases depends on pressure and temperature, it's preferrable to express ppm in weigtht by weight. In this case, it would be milligrams of oxygen per kilogram of mixture or grams of oxygen per metric ton of mixture (gas and oxygen).
Giovanni S. Crisi
Sao Paulo - Brazil

I don't understand: have you already received a lot of answers and now you're thanking who sent them?

By waccobird (****)

Date 11-30-2009 10:52

G.S.Crisi
I think he is thanking in advance hoping knowledge like yours will answer his question.
Marshall

By SWP

Date 11-30-2009 14:25

AWS D18.2:1999 shows a photograph of the inside surface of a series of 10 stainless steel tube welds where the purge was varied from 10 ppm to 25,000 ppm. At 50 ppm you just start to see a light straw (gold) discoloration.

By 3.2 Inspector (***)

Date 11-30-2009 16:22 Edited 11-30-2009 20:46

The extent of discolorration at 50 ppm will depend on which purge gas was used.

3.2

(Deleted by 3.2 Inspector)

Holy crap, what did I start?
Maybe the moderator is not aware that different gasses will give different outcome in regards to discolorration

(Deleted by 3.2 Inspector)

By ssbn727 (*****)

Date 11-30-2009 16:41 Edited 11-30-2009 19:32

Okay! So you mention different purging gases... What is the recommended purging gas for 654SMO?

Henry

By ssbn727 (*****)

Date 11-30-2009 17:16 Edited 11-30-2009 17:57

[deleted]

By 3.2 Inspector (***)

Date 11-30-2009 17:33

[deleted]

By ssbn727 (*****)

Date 11-30-2009 17:43 Edited 11-30-2009 19:43

[deleted]

By 3.2 Inspector (***)

Date 11-30-2009 17:46

My Formiergas is 90% nitrogen and 10% hydrogen.
I dont know about 2Ti as I have never heard that designation before.

3.2

By ssbn727 (*****)

Date 11-30-2009 17:57

Well, you are correct for question #1 However, I find it really troubling that you cannot recognize the grade 2 CP Ti which simply means Commercially Pure Grade 2 Ti. So now that I have clarified that for you, can you now answer the question?

Also, for question #1 what is the recommended torch gas for 654SMO when using the GTAW process? This will give you a chance to make up for you not being able to recognize CP Grade2 Ti. ;)

Respectfully, (this time you are earning it!)
Henry

By ssbn727 (*****)

Date 11-30-2009 18:02

Perhaps you can mull it over in your head while you give some advice to the gentleman in this thread who is asking a question that I know you might be familiar with:

http://www.aws.org/cgi-bin/mwf/topic_show.pl?tid=23367

Now remember to come back and answer the second part of question #1 and then you might by then have come up with an acceptable answer for question #2 as well! ;)

Repectfully,
Henry

By 3.2 Inspector (***)

Date 11-30-2009 18:07

Yes, I can answer this fine gentleman.
how can I answer about CP grade2 Ti, when I dont know what it is?

3.2

By 3.2 Inspector (***)

Date 11-30-2009 18:04 Edited 11-30-2009 19:34

For shielding gas when welding SMO I would use pure Argon or maybe a mix of Argon and Nitrogen.
For welding without filler Argon/Nitrogen is recommended, often required by client specifications.

3.2

By ssbn727 (*****)

Date 11-30-2009 18:15 Edited 11-30-2009 19:35

[deleted]

By 3.2 Inspector (***)

Date 11-30-2009 18:18 Edited 11-30-2009 19:32

3% Nitrogen.
3.2

By ssbn727 (*****)

Date 11-30-2009 20:35 Edited 11-30-2009 20:59

We weren't bickering at all moderator! We were actually having a decent discussion as well as as friendly bantor within the discussion... I believe you reads too much into it and overreacted this time... I suppose you're going to check every individual thread in every section as well to see how many have been "infected" also??? The posts were in fact related to the question of PPM's vs Per Cent by volume, so I cannot understand how you can say that we were bickering at all here.

Henry

By 3.2 Inspector (***)

Date 11-30-2009 20:47

For once I tend to agree with you.

3.2

By ssbn727 (*****)

Date 11-30-2009 16:09

Here you go:

This is probably the best of the bunch in this post:

http://209.18.104.171/uploads/docLib_33_UnitsConversionforDetectorTubes.pdf

The rest of these go more in depth with all kinds of situations and varying equations for different conversions as well:

http://www.epa.gov/apti/bces/module2/concentrate/concentrate.htm

http://www.engineeringtoolbox.com/ppm-d_1039.html

http://www.cbu.edu/~rprice/lectures/compos.html

Enjoy! :)

Respectfully,
Henry

http://www.air-dispersion.com/formulas.html

By Nanjing Date 11-30-2009 18:56 Edited 11-30-2009 19:33

What do you mean by sanitary applications? in the food industry, pharmaceutical etc ultra high purity argon is the norm (followed by pickling) and it is therefore easy to calculate O2 ppm.
3.2 Inspector, to avoid confusion, do not mention formier gas and titanium in the same paragraph! itIis a big no no (I know you did not say it is ok to use it but others may missunderstand).
On the subject of grade 2 titanium O2 content is kept to 10-20ppm. I used to buy the meters from Denmark as I could not get them in England.

By MBSims

Date 12-01-2009 02:19 Edited 12-01-2009 04:15

Okay, here is the way to convert % to ppm:

   1 ppm = 1 part / 1,000,000 parts = 0.000001

To convert to percent:

   0.000001 x 100% = 0.0001%

So, if your spec allows 10 ppm maximum:

   10 ppm = 10 parts / 1,000,000 parts = 0.00001
   0.00001 x 100% = 0.001%

To convert % to ppm, just do it the opposite way:

   0.0001% /100% = 0.000001
   0.000001 x 1,000,000 parts = 1 ppm

So, if your analyzer reads 1% oxygen content, the conversion to ppm is:

   1.0% / 100% = 0.01
   0.01 x 1,000,000 parts = 10,000 ppm

Try it on your calculator.

Now the question is - If your limit is on the order of 10 ppm, can your oxygen analyzer detect levels down to 0.001%?

By ssbn727 (*****)

Date 12-01-2009 09:40

Yes indeed! That's the ticket!

It depends on the way the detector tubes are calibrated and what types are sued in the design of the meter.. In other words, if they are calibrated to per cent by volume then usually not because they usually have higher detection ranges than detector tubes calibrated to let's say one part per million + or - 0.5 ppm (Not an actual calibration figure, but it represents basically how they are categorized based on sensitivity and there's a lot of other factors involved also)... So it all depends on the design of the meter and it's intended use.

Respectfully,
Henry

By Nanjing Date 12-02-2009 12:24

Thanks for the lesson in basic arithmetic but I knew that already (I was educated in Scotland!) As I have said previously you have to buy the right equipment. 25 years or so ago I could only get them from Denmark but you can buy them now from Huntingdon Fusion in the UK.

By jwright650 (*****)

Date 12-02-2009 12:35

Nanjing, The arithmetic wasn't posted for your benefit, it was posted for the OP's. He asked a question and was given an answer.

OP asked "Are there any simple formulas for figuring out how many ppm of oxygen there would be for every percent of oxygen detected when purging s/s. We only have a meter that reads in percent."

Marty answered him without any comments about anyone "Okay, here is the way to convert % to ppm:<snip>"

By MBSims

Date 12-02-2009 22:45

Yes, the post showed up directly after yours, but it was a reply to the original poster. I wasn't implying anyone's education was substandard, only trying to answer the original question.