Orifice meters are commonly used to measure flow rates, but they are highly non- linear devices. Because of this, special care must be taken when preparing calibra- tion curves for these meters. The equation relating volumetric flow rate V, to the measured pressure drop AP, across the orifice is V = ion in Excel AgCo2g ΔΡ VI-B¹ P For purposes of creating a calibration curve, the details of the equation are unimportant (as long as the other terms stay constant). It is necessary that we see the theoretical relationship between flow rate and pressure drop να VΔΡ. (6.12) ³Dr. Tom Bitterwolf's Honors Chemistry class at the University of Idaho. Data used with the permission of Dr. Bitterwolf. V (ft³. MIN) 3.9 7.9 11.8 16.7 19.6 23.6 27.5 31.4 36.3 39.3 (6.13) Also, the pressure drop across the orifice plate depends on the flow rate, not the other way around. So, VAP should be regressed as the dependent variable (y values) and the volumetric flow rate as the independent variable (x values): AP(psi) 0.13 0.52 1.18 2.09 3.27 4.71 6.41 8.37 10.59 13.08 a. Calculate VAP values at each flow rate from the tabulated data. b. Regress V and VAP, using Excel's Regression Analysis Package (found by selecting Tools/Data Analysis...) to create a calibration curve for this orifice meter. c. Check the line fit and residual plots to make sure that your calibration curve really fits the data.