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?
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 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.
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%?