| 摘要 |
PURPOSE:To know an uneven state of the inside of a tubular body and to enable the reproduction of the shape of the inside of the tubular body, by using a water distance measuring means to obtain data on water distance while driving transducers for transmitting and receiving ultrasonic waves which are arranged in the circumferential direction of a main body of pig. CONSTITUTION:A main body 1 of pig loaded with a measuring instrument measures the data on the shape of the inside of a tube while it runs by a pressure difference inside a tubular body 2. For this purpose, the distance of transfer of the main body 1 is measured by a range finder 11 and the rotational angle in the circumferential direction of the main body 1 inside the tubular body 2 is detected by an angle gage 12. A thickness gage 21, which is connected to each group of several transducers 6 for transmission and reception of ultrasonic waves provided in a plurality at prescribed intervals in the circumferential direction of the main body 1, transmits and receives ultrasonic waves while driving the transducers 6 and measures data on water distance to the inner surface of the tubular body 2. Based on a predetermined threshold value or the like as a reference, an encoder 24 selects these data and makes them recorded in a recorder 8. After the main body 1 is withdrawn, the data are read out of the recorder 8 and the shape of the inside of the tubular body 2 is restored by a method of interpolation. |
