Construction and Validation of Dew Point Probe Calibration Station
Valtavirta, Erno (2019)
Valtavirta, Erno
2019
Kaikki oikeudet pidätetään
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-201903143055
https://urn.fi/URN:NBN:fi:amk-201903143055
Tiivistelmä
The purpose of this study work is to construct and validate a calibration station for Vaisala oyj. The station will be used for calibrations of dew point measurement sensors produced by Vaisala. Customers will send their probes for calibration periodically to Vaisala Calibration and repair service (CRS) center. This calibration station will be used in Beijing CRS and it will expand the calibration capacity of the center in China.
Periodic calibrations of the measurement probes are needed, because the dew point measurement sensor readings have a tendency to drift. The drifting is caused by various contaminations entering the measurement sensor head from the measurement process, for example: when measuring atmospheric air there can be any number of impurities that will over a period of time pass the protective filter and cause the sensor properties to change. The probe then needs to be adjusted and calibrated to restore the original measurement accuracy of the probe.
The constructed station is a functional copy of station that was implemented before. Implementation of the station differs in the layout, transportability and ergonomics of the station. These features were determined from feedback by the previous stations users and the wishes of the constructed stations end users. Validation of the calibration station is also covered in this thesis. Initial validation was performed on the station to verify that the station is functional. Final validation of the station will be performed at the final operations site. Validation tests consist of a repeatability and comparison tests. In repeatability test the consistency of the calibrations were tested. Comparison test verifies that the station produces valid calibrations by comparing the produced calibrations to calibrations performed with proven station.
The station was constructed as planned. Initial validations were performed and the station was determined to be operational. The station was shipped to its site of operations in China where the final validations will be performed. After the validations have been completed the station can be used for customer probe calibrations.
Periodic calibrations of the measurement probes are needed, because the dew point measurement sensor readings have a tendency to drift. The drifting is caused by various contaminations entering the measurement sensor head from the measurement process, for example: when measuring atmospheric air there can be any number of impurities that will over a period of time pass the protective filter and cause the sensor properties to change. The probe then needs to be adjusted and calibrated to restore the original measurement accuracy of the probe.
The constructed station is a functional copy of station that was implemented before. Implementation of the station differs in the layout, transportability and ergonomics of the station. These features were determined from feedback by the previous stations users and the wishes of the constructed stations end users. Validation of the calibration station is also covered in this thesis. Initial validation was performed on the station to verify that the station is functional. Final validation of the station will be performed at the final operations site. Validation tests consist of a repeatability and comparison tests. In repeatability test the consistency of the calibrations were tested. Comparison test verifies that the station produces valid calibrations by comparing the produced calibrations to calibrations performed with proven station.
The station was constructed as planned. Initial validations were performed and the station was determined to be operational. The station was shipped to its site of operations in China where the final validations will be performed. After the validations have been completed the station can be used for customer probe calibrations.