| 摘要 |
PURPOSE:To eliminate a problem of torsion of a cable due to rotation of a detection pig in a tube to be measured, by a method wherein a shaft driven to be rotated and also to rotate the pig is made hollow and a photodetector and a light emitting element are respectively provided at both ends of the hollow shaft. CONSTITUTION:A light emitting element 57 is always emitting light by a current given through a cable 111 and a signal converter 56 of a rotary driver pig 50 from a processor 70. This light is photoelectrically converted to electric energy with a photodetector 18 of a detection pig 10 through a hollow part of a motor shaft 52 to be stored into a capacitor 19 and also to be supplied to an output circuit 16 and a light emitting circuit 11. Light emitting from a light emitting element 12 is projected through a projection lens 13 and a light projecting/ receiving window 100 and is reflected on the inner surface of a tube P to be measured. The reflected light is focused with a light receiving lens 14 and again passed through the window 100 to form an image on a one dimensional photodetector 15. Here, a signal is outputted to specify the light receiving element on which the image of the reflected light is formed, actuates an element 17 to perform a corresponding light emitting operation and an optical signal is sent to an element 58 to be converted into an electrical signal. This signal is amplified and converted with the signal converter 56 into a digital signal to be outputted to the processor 70. |
