| 摘要 |
PURPOSE:To provide a method for determining the extent of deterioration of cable coating material while laying the cable as it is without requiring any destructive sampling. CONSTITUTION:A probe P is applied to the outer peripheral surface of the coating material 12 of a cable 1 being laid and ultrasonic wave is transmitted from an ultrasonic transmitter S in the probe P toward the conductor 11 of the cable 1. The ultrasonic wave propagates through the coating material 12 and reflected on the conductor 11 before it is received by a receiver R. The velocity of ultrasonic wave propagating through the coating material 12 varies, as compared with that when the coating material is sound, according to the variation of breaking elongation due to deterioration of the coating material 12 and the variation corresponds to the extent of deterioration. Consequently, the extent of deterioration can be determined by determining the velocity of ultrasonic wave propagating through the coating material 12. |
