Detecting holes in pipe using radar unit moved longitudinally along pipe

摘要

The method uses a radar unit, moved along inside the pipe longitudinally, and at right angles to the movement direction across a transmitter aerial, arranged between two receiver aerials. The transmitter signals reflected at the pipe are received across the receiving aerials. The received signals are evaluated in an evaluation unit, and based on the evaluation, holes be established in the pipe and their position indicated. An amplitude modulated transmitter signal as a transmitter signal is continuously transmitted. The receiver signals after their detection, summation, amplification and demodulation, are converted in to DC signals, which are supplied to an evaluation unit. With the failure to reach a predetermined lower DC voltage signal level, the evaluation unit indicates the corresp. point in the pipe, identified as provided with a hole, and the position of this hole is indicated in the pipe.