It can be done. You have to consider the molecular weights of each gas and the proportion of each gas in the mix. Overall, it isn't worth the time and effort. Use the flow of the primary gas as the basis of your WPS. If you are working with a picky picky client, just record the flow rate when the PQR is qualified and note which scale you used.
Best regards -Al
The difference isn't great. On an L-tec 4 gas flowmeter[Nitrogen, Helium,Argon, Carbon Dioxide & C-25] I have the CO2 and C-25 are read on the same scale. the lines for CO2 & C-25 and for Argon practiclly line up at 30-40 CFH. Nitrogen is only 3-6 CFH higher in this range, but Helium would flow 100 CFH but only show about 35 CFH on an Argon meter. The readings on this meter are all at 50 psig.
thanks. i was aware that the difference was small, i was looking for a conversion table as i do have some very picky clients. thanks again for the replies
So then is it fair to say that Helium flows about 2.8 times faster than Argon does?
In other words, if 250 cf of He will expel in one hour, Argon will expel in 2 hours and 48 min?
Or is this not a reasonable assumption because the actual sale of the meter might not cross over at all flow rates?
Marcus
the density of the gasses is different. causing the cfh reading to be different for different gasses. if the scale does not allow readings of different gasses.
Marcus, this flowmeter has a square plastic tube with the bore for the ball through the middle. All readings are at 50 PSIG. The 2 scales are close but not exactly the same as follows:10 Ar - 20 He, 20 Ar - 55 He, 40 Ar - 120 He, 70 Ar - 220 He. It looks like the ratio is not constant. Hope this helps.