Abstract:
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Dew point sensors are used in industry to detect the presence of small levels of water vapor. Critical measurements in compressed air, breathing air, metals processing, battery making, plastics processing, natural gas and petrochemical production require water vapor levels to remain in the 1-6000 PPMv (parts per million by volume) or equivalent -76 to 0ºC Td (frost point temperature) range or less. Two Temperature/Two Pressure Generators are used to supply a test gas steam for calibrating and validating a wide variety of sensors and instruments. The system produces a controlled dew or frost point temperature (Td) by saturating air or other test gas at a depressed temperature in a pressure controlled vessel. The gas exiting the saturator is then depressurized and warmed to the test conditions. Chilled mirror hygrometers fundamentally measure dew or frost point temperature by controlling the temperature of metal mirror to an equilibrium point by the use of feedback from an infrared emitter and detector pair such that the mass of condensed mass of water (frost) is constant. A design of experiment and review of the expected uncertainty of the system will be presented.
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