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Originally Posted by airborn
Flow Rate Conversion [volume] sanity check...
I'm trying to measure small volume CFM (or ACFM) through an air line under pressure.
I have a liter/min flowmeter gauge. IF I convert the LPM to CFM
on the conversion WWW site...is this ACFM or SCFM ? I'm assuming SCFM...but the conversion says just "CFM".
Don't I have to factor in SCFM for my location (1-SCFM = about 1.064 ACFM for my location @ 75-deg F). Thanks !
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You need to know what you are trying to measure and what your instrument actually measures. The volume of a gas is a function of temperature and pressure. A box that holds 1 cubic foot holds 28.3495 L; that is a simple volume conversion. However, the amount of gas in that box is complex; it is usually restated to standard temperature and pressure, and is really an air mass, disguised.
Your problems are two fold:
*Metric gas measures normally use "normal," a pressure of 101.325 kPa and 0 °C, while foot based measures use 101.325 kPa and
several (non!) "standard" temperatures which differ by industry. Do you know what "standard" in scfm means in your industry?
*Compressed air volume is almost always measured as "free air" at the intake with corrections for pressure and temperature; it is NOT measured as a volume in the compressed state, but pressure is measured there. Do you know if your flow meter is calibrated to read equivalent free air or is it calibrated to flow at pressure?
Finally, do you want flow at free air conditions or at pressure?
08-05-2008, 06:15 AM
Air Pressur Conversion - LPM to CFM (or ACFM)
Linear Mode
