ASMI Flow Nozzle

[PFM]

Hello all,

Please help the rookie with a question, I have several ASMI Nozzles I know they were used on a high end air flow bench, I have some doccuments on them but no CFM numbers. The info is as follows, Effective Area .484823, Actual Pressure Ratio 1.049138, RH? 38.24, Mass Flow 0.071831, Corrected Mass Flow 0.071889. Now how one gets from this info to 55 CFM @ 15" water depression (measured) 0r 77 CFM@25" water depression is the info I seek.

Thanks in advance,

PFM

 

[jsummerfield]

First, I assume that you are refering to flow nozzles that conform with ASME MFC-3M-1989, Measurement of Fluid Flow in Pipes Using Orifice, Nozzle, and Venturi. These are volumetric flow meters.

Second, if the fluid density, temperature and pressure are the same, a square root relationship exists between the volumetric flow rate and the pressure drop. You can use this simple fact to adjust the pressure differential range for a higher or lower flow range.

Some generic flow calculation software exists, perhaps available on-line. Also, most flow element suppliers have software to calculate the pressure differential range given the details of the meter, and the physical properties of the fluid. Start with the supplier of those flow elements. If this does not work, you can find a contact supplier in your area from the ISA.ORG site where they have assorted instrumentation vendor listings.

John