2.6.1 Experiment 1: Calibration of Flow Meter: Rotameter Calibration of flow meters e.g. Rotameter. A flow meter is calibrated by comparing its displayed values with the results obtained from another, accurately verifiable measuring method. Procedure: - Prepare the HM 150 and the HM 150.13. - Switch on the pump on the HM 150. - The gate valve (6) on the HM150.13 and initially set a low flow rate. - Note the display value on the rotameter in a table (see Table 2.1) - Use the HM 150 to perform a volumetric measurement and note the result, and the time taken to obtain it, in the table. - Repeat the previous steps for at least five further settings of the gate valve (6) on the HM150.13. - Calculate the difference between the flow values recorded, calculate any error and plot the results in a graph