| 摘要 |
PROBLEM TO BE SOLVED: To be immune to noise, to transmit sound wave to a distance, to prevent attenuation of the waveform, and to accurately measure the pipe length. SOLUTION: In a state where a measuring mechanism 1 having a measuring part 11 and a measuring pipe 12 is connected to a pipe 3, a sound reception signal emitted from a microphone 103 arranged so that howling occurs in the measuring pipe is received from a speaker 102. Until a sound wave having a large amplitude by a speaker 102 and the microphone 103 occurs in the pipe 3 and a standing wave vector is detected, the frequency of a signal generated from a signal generation part 104 is changed and controlled, By using temperature data in the pipe and the peak frequency of the standing wave at that time, the pipe length is calculated by a control part 21 of a measuring device 2 based on a predetermined expression. COPYRIGHT: (C)2009,JPO&INPIT
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