| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic type gas analytical sensor constructed so that the intensity of sound waves is maintained by avoiding effects of a gas flow rate and preventing ultrasonic waves from being attenuated by diffusion, and the measurement accuracy is improved by reducing interferences by external noises when a composition of the two-component based gas is analyzed with the utilization of an ultrasonic element. SOLUTION: The element 1a for emitting ultrasonic waves and the element 1b for receiving ultrasonic waves are arranged to both ends of a gas passage tube 3, and a tube 4 for reflecting ultrasonic waves which has an inner diameter almost equal to a diameter of an emitting part of the emitting element 1a is inserted via a buffer material 8 into the passage tube. Diffusion holes 5 are set to the reflecting tube 4 in a manner to avoid a gas inlet 7a and a gas outlet 7b and to be distributed uniformly. A temperature sensor is set to a central part of a measurement chamber. The measurement gas is introduced from the gas inlet 7a to flow a gap between the gas passage tube 3 and the ultrasonic reflecting tube 4. A part of the measurement gas is diffused through the diffusion holes 5 to the measurement chamber 6, so that the effects of the flow rate is avoided, ultrasonic waves are prevented from being attenuated, and external noises are prevented from interfering effectively.
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