| 摘要 |
PURPOSE: To accurately measure the average temperature of a medium along a passage by detecting an acoustic wave transmitted through the medium in a high-temperature area with a transmitter and a receiver respectively provided at both ends of the area and measuring the speed of the acoustic wave in the medium by comparing the detected wave with a standard wave. CONSTITUTION: An acoustic transducer 40 generates an acoustic wave pulse in accordance with a signal from a processor 56 and another acoustic transducer 42 receives the pulse through a boiler 10. The acoustic signal received by the transducer 42 contains the acoustic wave pulse and the acoustic noise in the boil 10 and inputted to a processor 56. The processor 56 digitizes the received signal, compares the digital signal with a standard clear transmitted wave sample, and discriminates the maximum value of the correlation function between the sample and received sounds as the arrival time of the received wave. The speed of the pulse is calculated from the time required by the pulse for passing through the boiler 10 and the temperature of a medium is calculated by taking the specific heat and molecular weight of the medium into consideration. Therefore, the average temperature of the medium along a passage can be measured accurately.
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