| 摘要 |
PURPOSE:To obtain a sound-wave measuring instrument, wherein dust and the like are not attached to the tip of a waveguide for transmitting and receiving sound waves even if the temperature, the flow speed and the like of fluid containing a large amount of dust are measured. CONSTITUTION:In a sound-wave measuring instrument, the tip of a waveguide 2 is connected to the opening part of a duct side wall 1 surrounding fluid to be measured, and a sound-wave transmitter 3 and a sound-wave receiver 4 are provided at the other end. The transmitted signal from a waveform generator 6 is converted into the sound wave with the sound-wave transmitter 3, and the sound wave is transmitted into a duct through the waveguide 2. The sound wave, which is propagated through the fluid in the duct, is received with the other sound-wave receiver 4 and amplified with a receiving amplifier 9. The sound wave is converted into the digital value with an A/D converter 10. A propagation-time or attenuation-factor detector 11 obtains the propagating time of the sound wave in the duct or the attenuation factor during the propagation. A temperature/speed/concentration computing unit 12 obtains the temperature, the speed and the concentration of the fluid based on the obtained propagating time and the attenuation factor. A jetting port 14, which jets vapor or water toward the direction of the tip of the waveguide, is provided in the waveguide 2. |
