Welding Tips and Tricks

Does anyone have experience of using gas purifiers, which cleans inpurities down to 1 ppm or so?

Markus wrote:Does anyone have experience of using gas purifiers, which cleans inpurities down to 1 ppm or so?

Hi Markus
Sorry, I can't answer the question, but judging from the prices I pay for gas, I would've thought you couldn't get anything more pure!

You can pay for certified 'pure' argon, but typically most gas shops consider anything more than 99.999 percent (I think) homogenous 'pure', but you can pay for certificates of compliance stating that the bottle is 'more pure' than that. Then, if you have moisture in your argon or something like that, they will replace the bottle for free. Otherwise, they just chock it up to a bad batch and swap you another fill. The biggest problem is that most times, a bottle is bumped a few times back up to full before it actually gets evacuated properly, which saves backend costs, and time mainly for the gas supplier. But every time you do that you theoretically dilute the purity of the argon because you don't know what was actually in the bottle. And that 2ppm quickly becomes 15ppm where most agree that a noticeable effect on weld quality is seen.

what would you be welding that need that parameter?

My supplier lists several different types of argon:

Argon, Industrial Grade, Compressed
Shielding gas for MIG and TIG welding processes and for plasma cutting.
Welding and cutting a wide range of ferrous and non-ferrous materials.
Gas Properties: Colourless, tasteless and odourless. Inert to all materials at all temperatures and pressures.
Impurities: Oxygen 10ppm, Nitrogen 25ppm, Moisture 15ppm
Grade: Industrial Grade
Supply Mode: Cylinder
Brand: BOC
Application: Industrial
Industry: Industrial
Gas Code: 061
Type of Gas: Argon
Gas Composition: Argon greater than 99.995%


Argon, High Purity Grade, Compressed
Argon is one of the most commonly used carrier gases in gas chromatography. It is also the gas of choice for Inductively Coupled Plasma (ICO) spectroscopy.
Gas Properties: Colourless, tasteless and odourless. Inert to all materials at all temperatures and pressures.
Application: Specialty Gas
Grade: Scientific Grade
Supply Mode: Cylinder
Brand: BOC
Industry: Scientific
Gas Code: 062
Type of Gas: Specialty Gas
Gas Composition: Argon greater than 99.997%
Impurities: Oxygen less than 5ppm, Moisture less than 10ppm, Nitrogen less than 15ppm


Argon, Ultra High Purity Grade, Compressed:
Argon is one of the most commonly used carrier gasaes in gas chromatography. It is also the gas of choice for Inductively Coupled Plasma (ICO) spectroscopy.
Gas Properties: Colourless, tasteless and odourless. Inert to all materials at all temperatures and pressures.
Application: Specialty Gas
Grade: Scientific Grade
Supply Mode: Cylinder
Brand: BOC
Industry: Scientific
Gas Code: 262
Type of Gas: Specialty Gas
Gas Composition: Argon greater than 99.999%
Impurities: Hydrocarbons (as methane) less than 0.2ppm, Carbon Monoxide less than 0.2ppm, Carbon Dioxide less than 0.5ppm, Oxygen less than 1ppm, Hydrogen less than 1ppm, Moisture less than 2ppm, Nitrogen less than 5ppm

It seems that if we are looking for anything more pure than 99.995% Argon, it is classed as a specialty gas.

Incidentally, the price is almost double for 99.999% purity compared to the 99.995% job.

Cheers
Ranger

What do you need for ?

I know you Can get 99.9995% and 99.9999% That is also Call argon 6n or 6.0 there are also a 7.0 =99,99999% but dont wanne Price

Normaly welding gas, is 99,99%

Sorry for the delay in answering.

Yup there is ultra high purity gases available, but prizes are also sky high. Why I asked about purifiers then? Because I read this article those purifiers is used.

http://www.arcmachines.com/applications ... -gas-lines

I'm just wondering that how expensive gas purifiers might be?

Markus,
There are quite a few different gas purifiers on the market ranging from under $100 to many thousands of dollars. Problem is there are very few that can remove the multitude of impurities that can be in the gas. There are a number of processes to remove different impurities and each require different equipment so an in-line purifier is usually only good for one type of impurity. So when they say they can purify a gas to less than 1ppb, I would have to ask, less than 1ppb of what? A mole seive can do this for moisture, but not H2S, see what I mean. Usually you would need about four different kinds of in-line purifiers to obtain ultra high purity gas at the outlet, and then they only last a short while before they need replacement or regeneration.

If you're doing orbital welds for high purity tubing or laser welding these things might be practical, but for the average welder they would be overkill and not cost effective.

Len