| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for detecting the direction of rotation of a sensor pig, even in the case where an orientation meter cannot be mounted to the sensor pig. SOLUTION: Since the sensor pig 3 is provided with a plurality of sensors 7 along the inner circumference of a pipe 1, the whole surfaces of the circumference of the pipe 1 can be inspected. No measuring devices are provided inside the sensor pig 3. Sensor control circuits, range finders, recording devices, batteries, etc., are housed in the body parts of a front pig 2 and a rear pig 4, and a first angle meter 8 and a second angle meter 9 are provided for the front pig 2 and rear pig 4, to detect the angles in the circumferential direction of the front pig 2 and rear pig 4. The angle in the circumferential direction of the sensor pig 3 is computed through the use of the output of the two angle meters, to know which sensor corresponds to which location in the circumferential direction of the pipe 1. In one method, the angle in the circumferential direction of the sensor pig 3 is obtained from the weighted mean of the first angle meter 8 and the second angle meter 9 at the same time.
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