| 摘要 |
PROBLEM TO BE SOLVED: To detect the presence or absence of water under a steel plate 7 constituting a road even if there is a coating 8 on the steel plate 7.SOLUTION: A liquid detection device includes: a transmitting probe 5 for propagating a supersonic wave into a steel plate 7; a receiving probe 6 for receiving a transmitted wave propagating in the steel plate 7; and a transceiver 10 having a transmission part 11 for outputting an electric signal for driving the transmitting probe 5, a receiving part 12 for receiving a signal from the receiving probe 6, and a signal processing part 13 for obtaining the amplitude of the transmitted wave on the basis of an electric signal from the receiving part 12 and discriminating whether a material with which the steel plate 7 is in contact is liquid or gaseous matter. The transmission part 11 adjusts the frequency band of the electric signal for driving the transmitting probe 5 according to the thickness of the steel plate 7, and the receiving part 12 adjusts the frequency band of the electric signal from the receiving probe 6 according to the thickness of the steel plate 7. |
