| 摘要 |
PURPOSE: To obtain an ultrasonic distance measuring apparatus whose detection performance at a high temperature is enhanced by a method wherein a part of a wave-guiding rod is placed in a high-temperature atmosphere, a probe is attached to the surface of the wave- guiding rod other than the part and a shielding member which has interposed a substance whose acoustic impedance is largely different is installed at the side face of the wave-guiding rod. CONSTITUTION: A transmitting probe 1 and a wave-guiding rod 2 for transmission are compression-bonded by a probe holder 3 via a contact medium, and a receiving probe 4 and a wave-guiding rod 5 for reception are compression-bonded by a probe holder 6 via a contact substance. A substance whose acoustic impedance is largely different, e.g. the air, is interposed between side faces of the wave-guiding rods 2, 5, and shielding members 7, 8 which shield respective interference noises are attached by using a heat-resistant adhesive 9. The wave-guiding rods 2, 5 are fixed at a constant interval by using a fin 10 for cooling, and a part of them is placed in an ultrasonic propagation medium 11 in a high-temperature atmosphere such as a molten metal or the like. The probes 1, 4 are attached to surfaces of the wave-guiding rods 2, 5 other than the part, and the distance is measured by an ultrasonic distance measuring part 13 on the basis of the required time of ultrasonic waves in the back and forth route of the prove 1→the wave-guiding rod 2→an object 12 to be measured→the wave-guiding rod 5→the probe 4.
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