Distinguishing between directed and reflected ultrasonic signals generated by a compressed air leak source based on spectral analysis

The principle of compressed air leak ultrasonic detection in pneumatic systems was introduced. The detection mistakes caused by a reflected ultrasonic was analyzed and a method solving this problem through distinguishing a reflected ultrasonic was proposed. Compressed air leak directed and reflected ultrasonic signals were studied through measurement tests. The obvious differences between the spectra of directed and reflected ultrasonic signals were found and analyzed. An algorithm for distinguishing a reflected ultrasonic was designed and using it the reflectance characteristic coefficient (RCC) of the reflected ultrasonic was calculated. From the case study, it was shown that the RCC value of a directed ultrasonic signal is below 100 while that of a reflected ultrasonic signal is above 200. The results were valuable for distinguishing a reflected ultrasonic and avoiding detection mistakes caused by a reflected ultrasonic in ultrasonic leak detection.