| Gas transportation has become one of the five biggest transportation businesses which plays an important role in national economy and production. At present gas transfer project from western to eastern has been started roundly. During the Tenth-Five Plan, nearly twenty thousand Km pipe-net of "gas transfer from western to eastern" were finished. According to the investigation from the pipe-engineering department, most of eroding holes and pressure cracks in underground pipe appear not in the external surface but the inner surface. So detecting the inner pipe is more important than the external of pipe. Besides these, the pipes' wall will be thicker in their usage, which affects the safety of pipe seriously. The present way to solve the problem is to change the whole pipe. But it wastes much money. So it is very important to develop a new detecting system to solve this problem.A set of moveable detecting equipment of car with rollers is introduced in this paper, which is appropriate to pipes with 20cm diameters. The body of the car is composed of sleeve pieces jointed by universal joint. The detecting device are set on each sleeve piece. A roller ultrasonic probe was designed in the subject, and it sends ultrasonic wave to detect the pipe wall's thickness. In the roller ultrasonic probe is a ultrasonic focusing probe which can strengthen the signal. When this detecting system works inside the pipe independently, programs saved in MCU in the car can control all the moveable car system. At the same time, the data of signal and image of pipe wall are... |
