Calibrate the rotameter with the ball at the settings designated by the instructor. Take readings at the center of the ball. To calibrate, take three soap bubble meter readings at each rotameter reading. Use a stopwatch to time the transit for a pre-determined volume. Record in Table 1 below

Table 1 Rotameter Reading Volume (milliliters) Time (seconds)

1 -1000 58.23

1 -1000 60.15

1 -1000 57.87

2 -1000 28.53

2 -1000 29.78

2 -1000 28.66

3- 1000 19.00

3 -1000 19.54

3 -1000 20.01

3. A. Remove the cassette from the system. B. Set the rotameter to setting designated by instructor. C. Check the flow three times with the bubble meter. Record Data in Table 2 Below

Table 2 Rotameter Reading Volume (milliliters) Time (seconds) Volume (liters)

2.3 -1000 23.45

2.3- 1000 22.78

2.3 -1000 22.3

1 Complete the Flowing Calculations and graphs. A. Determine the flow rates in liters per minute by using the following. Information for calculation of flow rate: 1) Convert milliliter to liters: 1000 ml = 1 L 2) Convert seconds to minutes: 60 seconds = 1 minute 3) Calculate the flow rate at each point using the formula. Q = V/ t Where Q = flow rate in liters per minute V = volume in liters t = time in minutes B. Using the data from Practical Exercise step 2, Plot the rotameter readings (X) versus the calculated flow rates (Y) on a linear graph. Determine a least squares fit of the data (linear regression) Y = mX + b. Where calculated flowrate is the Y variable and rotameter reading is the X variable, m is the slope (X variable coefficient in Excel) and b is the intercept (Intercept coefficient in Excel). Note: Regression can be conducted in Excel.

Make sure to include a copy of the graph of data and results of regression when turning in lab. Regression Equation: Y = _____ X + ______ Goodness of Fit: r2 = _________

C. Based on the calibration curve determine the expected flow rate for the rotameter reading used in part 3. Note: you will need to use the regression equation developed in part B above. Expected Flow Rate =___________

D. Error calculations % Error = [(Observed – Expected) / Expected] * 100 Where: Observed is the measured value and Expected is the actual or theoretical value. Assume that the observed value is the flow rate measured in Part 3 and the expected value is the flow rate calculated in C above.  

Practical Exercise #2: Calibration of a rotameter with an electronic meter 1. Arrange the apparatus as shown. Note: The pump draws air. The air flow starts at the inlet (bottom) of the rotameter.  

2. Calibrate the rotameter with the ball at settings as indicted by the instructor. Take readings at the center of the ball. To calibrate, take three electronic meter readings at each rotameter reading. Record data in table 3 below.

Table 3 Rotameter Reading Flow Rate (lpm) Average

0.5- 0.481

0.5- 0.492

0.5- 0.499

1 -0.975

1 -0.989

1 -0.979

1.5- 1.423

1.5- 1.475

1.5- 1.483

2 -1.899

2 -1.924

2 -1.967

2.5- 2.478

2.5- 2.483

2.5 -2.480  

3. A. Remove the cassette from the system. B. Set the rotameter to setting as indicated by instructor. C. Check the flow three times with the bubble meter. Record data in Table 4 below.

Table 4 Rotameter Reading Flow Rate (lpm) Average

1.2- 1.220

1.2- 1.208

1.2-1.212

Complete the Flowing Calculations and graphs. A. Using the data from Practical Exercise step 2, Plot the rotameter readings (X) versus the calculated flow rates (Y) on a linear graph. Determine a least squares fit of the data (linear regression) Y = mX + b. Where Electronic meter flow rate is the Y variable and rotameter reading is the X variable, m is the slope (X variable coefficient in Excel) and b is the intercept (Intercept coefficient in Excel). Note: Regression can be conducted in Excel. Make sure to include a copy of the graph of data and results of regression when turning in lab. Regression Equation: Y = _____ X + ______

Goodness of Fit: r2 = _________

B. Based on the calibration curve determine the expected flow rate for the rotameter setting in part 3. Note: you will need to use the regression equation developed in part B above. Expect Flow Rate =___________

C. Error calculations % Error = [(Observed – Expected) / Expected] * 100 Where: Observed is the measured value and Expected is the actual or theoretical value. Where: Observed is the measured value and Expected is the actual or theoretical value. Assume that the observed value is the flow rate measured in Part 3 and the expected value is the flow rate calculated in C above.  

Write a Letter of Calibration In the space below: Answer the following questions about your laboratory data and laboratory process It is important to provide an explanation to justify your answers. APA rules must be followed scores will be affected by poor writing of items. The letter must look professional and use APA rules. You will be writing a letter of calibration to the customer who has obtained your services as an IH. You must write in you letter the following items: 

a. What is calibration and when should you perform calibrations with sampling equipment? 

b. What is your acceptable level of error (compared to the slope of 1) and does your measurements meet this level? 

c. What are the methods of calibration used in this lab (they must be named)? 

d. A chart for both methods used showing your data must be in the letter.