| 摘要 |
PURPOSE:To measure the gas component in good respondency by forming the gas introducing tube part into a cell to the double-tube structure for reference and sample gases and situating the opening surface in the vicinity of the center part of a piezoelectric element plate formed with a gas sensitive film. CONSTITUTION:The humidity measuring cell 9 contains a humidity sensor 3 forming a humidity-sensitive film 33' at the center part of the surface of the piezoelectric element plate 31 through a film electrode 32, and consists of a gas exhausting tube part 2 and a cell vessel 4 having the tubes 10, 11 for introducing the sample and reference gases. The opening part 12 of the tubes 10 and 11 in the cell is of double-tube structure, and the opening surface 13 opposes at the vicinity of the center part of the plate 31. The reference gas and the sample gas are allowed to flow alternately, and the humidity of the sample gas is measured from the variation of the response of the sensor 3. The adverse influence due to the gas adsorption is decreased by separating the introducing tubes for the reference and sample gases, and the respondency and sensitivity of the humidity sensor are improved by introducing the gas to the center part of the piezoelectric element plate under the double-tube structure condition. |
