Mechanical Engineering Department
Loyola Marymount University
Los Angeles, California
In this laboratory experiment, an Omega Model PX- 236-060GV piezoresistive pressure transducer was calibrated, by using an AMTEK model deadweight pressure tester. For the temperature calibration an Jofra Model C-140 temperature calibrator was used. The experiment began by setting up the Jofra Model C-140 temperature calibrator, and taking data from two systems, which were different temperatures. Then the lab went into measuring the outputs of the pressure transducer at different pressures. In conclusion the pressure calibrator and temperature calibrator were proved to be accurate in their measurements through the use of plots, data analysis and statistical analysis methods.
TABLE OF CONTENTS
Results and Discussion
Conclusions and Recommendations
The goal of this lab project was to calibrate temperature and pressure measurement systems. The systems we calibrated, were the Omega Model PX-236-060GV Piezoresistive Pressure Transducer, a thermocouple, and a thermistor. In order to obtain more accurate and precise readings, an AMTEK Model RK Deadweight Pressure Tester was utilized to calibrate an Omega Model PX236-06GV Piezoresistive Pressure Transducer. We had to add metal plates in increments of 5 psig until we reached 60 psig to a deadweight tester. The way we used the results was by using them to calculate the percent error and standard deviation. The results that were expected were that this calibration experiment would use two methods of calibration which both would work well. These results can be used by manufacturers so that less possible mistakes can be done when taking measurements.
Calibration is a comparison between measurements, one of known magnitude or correctness made or set with one device and another measurement made in as similar a way possible with a second device. The device with the known or assigned correctness is called the standard. The second device is the unit under test which is the device being tested. Furthermore temperature calibration is tested using thermocouple and a thermistor. The thermocouple is a junction between two different metals that produces a voltage related to a temperature difference. The thermistor is a semiconductor device that has a negative temperature coefficient of resistance, in contrast to the positive coefficient displayed by most metals. |
Figure : Temperature calibration system (Angelica, 2010) | |
Figure : Pressure calibration system (Angelica, 2010)|
The following equipment and materials used in the experiment were: * Jofra model C-140 Temperature Calibrator
* Probe including a thermistor and K-type thermocouple
* Keithley Model 175 A digital multimeter
* Tegam Model 819 digital temperature measuring system
Figure : Jofra model C-140 Temperature Calibrator|
The experiment procedure was as follows:
* For the temperature calibrations measure and record the output of the two systems at temperatures ranging from 0o C to 100o C in 10o C increments * Then the Jofra calibrator will automatically provide the various temperatures * Then it will take 6 – 7 minutes to produce the desire temperature at steady state * For the thermistor you will measure the resistance
* For pressure calibrations measure and record the pressure transducer output at applied pressures starting at 0 psig increasing up to 60 psig in increments of 5psig
RESULTS AND DISCUSSION
Instrument calibration is one of the primary processes used...