Flow Detection Technology Research Based On Ultrasonic

Flow meters are indispensable instruments in the development of industry. The developments of flow meters towards intelligence and automation are very essential especially in the field of petroleum energy industry. In order to meet the demands of oil production sites, this dissertation explore and developed a flow meter based on ultrasonic detection method.Operating principles of the ultrasonic Doppler flow meter are analyzed in the first place. The corresponding flow rate measurement model based on ultrasonic Doppler method is built in the second place. Next, circuits of detection processing are designed and prototype machines of this new type ultrasonic flow rate meter are constructed. Meanwhile, calibration tests for ultrasonic flow rate measurements are performed. In the process of designing measurement circuits, anti-interference performance and electromagnetic compatibility are fully considered, and many studies are made in the process of choosing electronic components and chips. In improving the overall measurement accuracy, drawing on the previous design experience, focusing considered weak signal acquisition, key components of the selection, the whole layout, electromagnetic compatibility, interference and other details of the design.In our laboratory conditions, relative electromagnetic compatibility experimental tests have been carried out and results show that anti-interference capability of the ultrasonic flow rate measurement circuit hardware meets the requirement of normal operation. Interferences from frequency converter are measured in a lot of experiments such that adequate measurement precision can be reached. By adding proper filter to the power ports of the frequency converter, these interferences are suppressed effectively therefore interference problems are solved.In order to verify the reliability and precision of this system, firstly, a suit of prototype machines are devised and equipped using the existing devices and pipes in the laboratory. Then a series of feasible testing methods are proposed and an amount of calibration experiments are performed. The experimental results demonstrate that the precision of this flow meter increases significantly compared with competing products now available. Finally, this ultrasonic flow meter has also reached reliable and stable performance. The test conclusions show that the flow meter has high reliability, stability, electromagnetic compatibility and accuracy, comparison of previous designs in terms of accuracy and performance has improved to some extent, can better meet the needs of industrial measurement, meanwhile, the foundation has been laid a certain for further improve the measurement accuracy of the subsequent research.