| 摘要 |
PURPOSE:To enhance inspection efficiency and to improve inspection accuracy, by reflecting light from a light emitting element by a rotary mirror to irradiate the film on the inner surface of a pipe to be inspected to perform rotary scanning and receiving the change in the quantity of reflected light by a photoelectric converter element. CONSTITUTION:The laser beam generated from a semiconductive laser element is condensed by a lens to be projected to a pipe to be inspected in the center axis direction thereof and reflected by a rotary mirror to irradiate the inner wall of the pipe to be inspected as a spot with a diameter of 1mm or less. The photoelectric converter element of a light receiver receives weak reflected beam from the surface of the film on the inner surface of said pipe to photoelectrically convert of reflected beam. This electric signal is amplified by an amplifier 20 through a connection cable 16 to be inputted to a cathode ray tube oscilloscope 22 of a cathode the through a differentiator 21 and receives the observation of a wave form to be automatically recorded on a pen writing oscillograph 24 through a peak hold circuit 23. When there was a voltage signal exceeding the threshold value preset by a comparator 25, that is, the increase in the quantity of reflected beam, an alarm is emitted by an automatic alarm 26 to discriminate the pressure of a coating inferior part. |
