Calculation of Differential Range - Intergraph Smart Instrumentation - 13.1 - Reference - Hexagon PPM

Integraph Smart Instrumentation Sizing Equations

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  1. Calculate internal pipe diameter at flow temperature:

  2. Calculate correction factor for steam quality (for liquid, water, and gas, Fs=1):

  3. Calculate orifice diameter at flow temperature.

    1. For Lo-Loss tube, Nozzles, and Venturi tubes:

    2. For other orifices:

  4. Calculate pipe Reynolds number:


  5. Calculate b -ratio.

    1. For all Flow meters except Segmental orifices:

    2. Segmental orifices.

      1. Calculate Segmental radius:

      2. Calculate b -ratio:

        HS is calculated with the help of HS0 in accordance with step 3b.

  6. Calculate Discharge coefficient, see Appendix.

  7. First estimate for Differential range:

  8. Calculate gas expansion factor (for liquid and water, Eps=1).

    1. For square edge orifice with 2½D and 8D pipe taps:

    2. For Lo-LOss tube, Venturi tubes and Nozzles:

    3. For eccentric orifices:

    4. For square-edge orifices specified in ISO 5167 - 2003 (flange tappings, corner tappings, and radius tappings):

    5. For other Flow meters:

  9. Calculate new Differential range:


  10. For liquid and water, got to step 13.

  11. Calculate the relative change in differential range:

  12. Repeat steps 8 to 11 until the relative change in the differential range is less than 0.0001.

  13. For quarter of circle (Quadrant Edge) orifice, calculate radius of upstream profile: