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[7p-A411-9] Stability improvement by temperature and pressure-calibration for the pressure sensor using a quartz oscillator in outdoor use
Keywords:hydrogen sensor, hydrogen society, fuel cell
The stability improvement of the pressure sensor using a temperature-stable quartz oscillator is necessary for the practical application to a hydrogen sensor for outdoor use because the sensor output is influenced by atmospheric pressure, temperature, and humidity. In this study, this was accomplished by preamp-temperature- and pressure- calibration of the sensor output. The pressure-calibration of the sensor was carried out using the pressure dependence of the sensor output at around the atmospheric pressures in our previously report. The change in the sensor output induced by the change in pressure can be calculated by the pressure dependence of the sensor output, thereby, the sensor output can be pressure-calibrated by subtracting the calculated change in the sensor output induced by the change in pressure using the pressure dependence. The sensor output linearly increased with atmospheric pressure.
The sensor output is also influenced by temperature at the preamp which is connected to the sensor and increased linearly with preamp-temperature. As well as the pressure-calibration, the sensor output was preamp-temperature-calibrated using the preamp-temperature dependence of the sensor output with keeping other conditions constant. The sensor output can be both calibrated above by preamp-temperature-calibrating the pressure-calibrated sensor output.
Sensor output, preamp temperature, atmospheric pressure, temperature and humidity were measured consecutively for 24 hours for several months at outdoor.
The sensor output normally fluctuated more than 1% of the average for 24 hours, which is unacceptable level as a hydrogen sensor. However, the stability in both calibrated sensor output was drastically improved compared to the pressure-, the preamp temperature-, and the experimental sensor output for 24 hours.
Finally, it was shown that the calibration method developed in this study is sufficiently effective to improve stability in the output from the pressure sensor below 0.33% for long time measurement, which is the necessary level for practical use of a hydrogen sensor in outdoor environments.
The sensor output is also influenced by temperature at the preamp which is connected to the sensor and increased linearly with preamp-temperature. As well as the pressure-calibration, the sensor output was preamp-temperature-calibrated using the preamp-temperature dependence of the sensor output with keeping other conditions constant. The sensor output can be both calibrated above by preamp-temperature-calibrating the pressure-calibrated sensor output.
Sensor output, preamp temperature, atmospheric pressure, temperature and humidity were measured consecutively for 24 hours for several months at outdoor.
The sensor output normally fluctuated more than 1% of the average for 24 hours, which is unacceptable level as a hydrogen sensor. However, the stability in both calibrated sensor output was drastically improved compared to the pressure-, the preamp temperature-, and the experimental sensor output for 24 hours.
Finally, it was shown that the calibration method developed in this study is sufficiently effective to improve stability in the output from the pressure sensor below 0.33% for long time measurement, which is the necessary level for practical use of a hydrogen sensor in outdoor environments.