Development Of An Ultrasonic Testing System For Pressure Vessel Based On ARM Processor

Pressure vessels are commonly used in industrial production, such as petroleum, chemical, metallurgy, medicine industry and fields of people’s lives. In order to ensure smooth production process, measure of the pressure vessel is important. In order to avoid undermining the pressure vessel in the process of pressure detection and reduce the risk of accidents, non-destructive testing technology has been widely used. As the non-detructive testing, ultrasonic testing has advantages of high sensitivity, high speed, low cost, harmless to person, and it can locate and quantify the defect points. Especially for the equipments woried under high temperature, high pressure and corrosive conditions, it is necessary to avoid damaging the equipment from raw materials testing to regular checks in daily work.On the basis of research and analysis of the principle of ultrasonic testing, a system for ultrasonically testing the pressure vessel is designed. The system is based on the ARM processor and runs on the embedded Linux system. Compared to the traditional testing equipment, it has many advantages. For example, the testing results can be stored in file system of the flash memory, SD card or USB flash disk, and it can also be stored to the computer via USB or other serial communication for further analysis and research. In fact, the directly obtained data of the device is the ultrasonic transmission time for measuring the specifically set distance, so that the velocity of ultrasonic surface wave in the medium can be calculated. The averaging value from repeated measurements was adopted to reduce the random noise. The reference method (two receiver probes are set) to eliminate the affect of the time delay by the electronic device in the circuit.In the thesis, firstly, the ultrasonic testing theory and technology were carefully studied. And on this basis, the overall design scheme of the embedded ultrasonic pressure vessel detection system based on ARM processor is proposed. Thus both the hardware and software can be designed. Secondly, the detailed description of the overall hardware design of ultrasonic detection system for the pressure vessel is given, which includes the ultrasonic control module, excitation module, receiving module, TDC timing module and communication interfaces. And then, on the basis of hardware devices, transplantation of the Linux system software, hardware driver and the applications is described (the driver and application for TDC-GP21 is most important). The modular hardware design makes the system is more reliable and adjustable. And the structure of modular software makes the programming is easier and also benefits for further maintenance and upgrade. Finally, the lack of work and future research directions is summed up.