Before a rotameter can be used to measure an unknown flow rate, a calibration curve of flow rate versus rotameter reading must be prepared. A calibration technique for liquids is illustrated below. A flow rate is set by adjusting the pump speed; the rotameter reading is recorded, and the effluent from the rotameter is collected in a graduated cylinder for a timed interval. The procedure is carried out twice for each of several pump settings.

(a) Assuming the liquid is water at 25oC, draw a calibration curve of mass flow rate, m (kg/min), versus rotameter reading, R, and use it to estimate the mass flow rate of a water stream for which the rotameter reading is5.3.

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ROTAMETER VARIABLE SPEED PUMP THCHEY STOPWATCH GRADUATED CYLINDER Rotameter Collection Reading Time (min) 2 2 4 4 6 6 8 8 10 10 1 1 1 1 0.5 0.5 0.5 0.5 0.5 0.5 Volume Collected (cm³) 297 301 454 448 300 298 371 377 440 453