Calibration of Load Cells
Team Members
Marc Moss
Brian Vandagriff
November 10, 1998
Summary
A drying oven is used to dry particulate samples. When performing experiments it is useful to know the drying rates of the samples. In order to perform such tasks, it is necessary to weigh the samples at various time intervals to determine the amount of water evaporated. A convenient way to avoid having to remove the samples from the oven is to suspend the trays from cantilevered members with attached load cells.
The drying oven analyzed during this experimentation is located in the Administrative Building. The objective of the experimentation was to calibrate the load cells used in the drying unit. Seven known masses were obtained and weighed using a balance scale. The known masses were then placed into the trays to determine the voltage change in the strain gages, which is displayed on LabView. The data for all eight trays was recorded and calibration curves were made with Excel.
Introduction
The objective of the experimentation was to calibrate the load cells used in the drying unit. Seven known masses were obtained and weighed using a balance scale. The known masses were then placed into the trays to determine the voltage change in the strain gages, which is displayed on LabView. The data for all eight trays was recorded and calibration curves were made with Excel.
Background
The process of drying is a method of thermally removing a liquid from a solid. In a direct heat, cross-circulation dryer, fresh air is drawn into the oven and passed over the heating element by the blower. It is then circulated through the oven and the moist air is exhausted through a vent located on the side. The wet solids are place in trays, which are suspended in the dryer. As the temperature rises the water in the solids evaporates.
Figure 1. Drying Oven
Procedure
- Used four individual masses and made three combinations of the four to total seven mass data points used in the calibration process.
- Masses were weighed on a balance scale.
- Masses were placed into the eight trays provided in the drying oven.
- Potentials were recorded for each of the seven masses in each tray.
- Used Excel to plot calibration curves.
Results
The results are provided in Tables 1 through 8 and the corresponding Charts 1 through 8.
Table 1. Tray 1 Data
Comp. Display (V) / Mass (g)0.2 / 147.5
0.37 / 263.25
0.41 / 295
0.615 / 448.2
1.05 / 743.2
1.27 / 890.7
1.61 / 1153.95
Table 2. Tray 2 Data
Comp. Display (V) / Mass (g)0.24 / 147.5
0.4 / 263.25
0.45 / 295
0.67 / 448.2
1.1 / 743.2
1.31 / 890.7
1.69 / 1153.95
Table 3. Tray 3 Data
Comp. Display (V) / Mass (g)0.14 / 147.5
0.25 / 263.25
0.29 / 295
0.44 / 448.2
0.75 / 743.2
0.89 / 890.7
1.16 / 1153.95
Table 4. Tray 4 Data
Comp. Display (V) / Mass (g)0.24 / 147.5
0.41 / 263.25
0.45 / 295
0.67 / 448.2
1.1 / 743.2
1.31 / 890.7
1.69 / 1153.95
Table 5. Tray 5 Data
Comp. Display (V) / Mass (g)0.24 / 147.5
0.41 / 263.25
0.45 / 295
0.67 / 448.2
1.1 / 743.2
1.31 / 890.7
1.68 / 1153.95
Table 6. Tray 6 Data
Comp. Display (V) / Mass (g)0.235 / 147.5
0.4 / 263.25
0.45 / 295
0.67 / 448.2
1.09 / 743.2
1.3 / 890.7
1.67 / 1153.95
Table 7. Tray 7 Data
Comp. Display (V) / Mass (g)0.22 / 147.5
0.36 / 263.25
0.4 / 295
0.58 / 448.2
0.94 / 743.2
1.12 / 890.7
1.45 / 1153.95
Table 8. Tray 8 Data
Comp. Display (V) / Mass (g)0.295 / 147.5
0.46 / 263.25
0.505 / 295
0.73 / 448.2
1.15 / 743.2
1.36 / 890.7
1.735 / 1153.95
Discussion
All calibration curves constructed were linear. The equations from linear regression will be used in the LabView setup to calibrate the display provided for the user.
Conclusions/Recommendations
We recommend that the data obtained in this experiment should be input into the LabView setup as soon as possible.