Argon Flow meter with Nitrogen

[Originaldon]

I have spent the last few weeks reading on the Exit Bag / Nitrogen method. I am quite clear on the method and equipment. The information on here is enough for anyone to be able to competently carry out this method successfully.

However the only question I have is that I have read conflicting information on the use of an Argon Flow Reg an the conversion for use with Nitrogen. I calculated a flow of 12-13LPM which is also backed up in @greenbergs blog. However on this site I have read people saying it needs to be increased to 17-19LPM.

Can anyone confirm what the correct conversion is?

 

[mandyjohnuk]

Hi.
I have the same set up. I was advised the same by the same person. He seems to be very knowledgeable so it would seem to ring true. Anything else is just that. See my posts to see if your regulator is similar to mine.

 

[Greenberg]

I have spent the last few weeks reading on the Exit Bag / Nitrogen method. I am quite clear on the method and equipment. The information on here is enough for anyone to be able to competently carry out this method successfully.

However the only question I have is that I have read conflicting information on the use of an Argon Flow Reg an the conversion for use with Nitrogen. I calculated a flow of 12-13LPM which is also backed up in @greenbergs blog. However on this site I have read people saying it needs to be increased to 17-19LPM.

Can anyone confirm what the correct conversion is?

You have the correct result, my friend. Best!

 

[Riomhaire1]

Can you flow different gas through an uncalibrated device

Often it becomes necessary to use another gas through a flow control device such as a flowmeter, flowmeter regulator, or flow gauge regulator. While the flow control device may be safe and compatible for the other gas, the issue often becomes one of accuracy.

www.harrisproductsgroup.com

It depends what you are doing. If using an argon calibrated flowmeter but with N2 gas - then it will over read - multiply by 0.84 -- so apparent 12.6 litres is actually 15 litres N2
If instead you are putting Argon gas through a N2 calibrated flowmeter, it will under read - divide by 0.84 - so apparent 17 litres is actually 15 litres Argon

I am not selling anything - or referring you to any webpages that I have any profit/interest in.

 

[Greenberg]

Can you flow different gas through an uncalibrated device

Often it becomes necessary to use another gas through a flow control device such as a flowmeter, flowmeter regulator, or flow gauge regulator. While the flow control device may be safe and compatible for the other gas, the issue often becomes one of accuracy.

www.harrisproductsgroup.com

It depends what you are doing. If using an argon calibrated flowmeter but with N2 gas - then it will over read - multiply by 0.84 -- so apparent 12.6 litres is actually 15 litres N2
If instead you are putting Argon gas through a N2 calibrated flowmeter, it will under read - divide by 0.84 - so apparent 17 litres is actually 15 litres Argon

I am not selling anything - or referring you to any webpages that I have any profit/interest in.

I think it is important to show how you reached the calculation considering the flow rate setting is crucial for successful CBT and to fully ensure that the OP has the correct setting. Finally, I am not selling anything but sharing knowledge with the community. Best!

 

[Originaldon]

Thanks for the replies guys. As mentioned I'd calculated 12-13lpm and wanted to confirm after seeing mentions of bumping it up.

 

[thisSideUp]

I arrived at this thread and checked all the figures in the site (here is an updated link with a correction factors table). I understand that the table is constructed with the following formula:
Q2 = Q1 * sqrt(G1/G2)

where:
Q1 is the apparent meter reading,
G1 is the specific gravity (weight in ratio to that of air with the same volume) of the gas for which the regulator is calibrated,
Q2 is the actual volume of the gas you are flowing, and
G2 is the specific gravity of the gas you are actually flowing.


For example, if you are flowing nitrogen gas with an argon-calibrated regulator, the correction factor is the square root of 1.37/0.97 (= 1.18843... ≈ 1.19), given that the specific gravity of Ar is 1.37 and that of N2 is 0.97. If you want a flow rate of 15L/min., your meter should be at 12.6 (or 15/1.19).


I still don't understand the chemistry/physics behind those data. Anyone?