Ahmad Keshavarz

One of the issues that the gas company is facing is finding underground polyethylene gas pipes that have been taken into consideration. There are several ways to find underground polyethylene gas pipes, each with its own advantages and disadvantages. This faces to some problems such as fault due to gas branching and other buried pipes, the time consuming and the need to cut off the gas of the under test area. One of the methods of finding the underground polyethylene gas pipes is using acoustic method. In this project, based on this method, gas pipe locator device is designed, manufactured and tested. In this device, after the removing of the gas Regulator, by connecting the acoustic transmitter to the gas pipe, an audio signal is sent into the pipe and then the test area scanned using a geophone. According to the experiments and simulations, it was found that, depending on soil type, moisture content and soil compactness, there were certain frequencies that the geophone received the most power on the gas pipe. Accordingly, the received signal is first analyzed by sending an acoustic chirp signal into the pipe and receiving the signal from the geophone. In order to properly analyze the received signal, the effects of environmental noise have been eliminated. Then more power frequencies are selected. Finally, by sending selected frequencies into the pipe and scanning the test area, the pipe location is estimated. The device was able to detect the pipe location with an error of less than 20 cm in field tests in Bushehr, which was done in coordination with the Bushehr gas company.