Application Research For The Online Corrosion Monitoring System Based On Ultrasonic Technology

In recent years,the portable ultrasonic thickness meter based on the principle of the pulse reflection type ultrasonic thickness has used widely in the pipeline and vessel wall thickness of offline testing field.However,it cannot satisfy the requirements for some particularly serious corrosion occasions.To ensure the production safety,we need the long-term real-time online monitoring to play an accident warning function.The foreign scholars have proposed an ultrasonic corrosion online monitoring scheme that the ultrasonic testing equipment installed in the pipeline by the waveguide technology.However,the domestic corrosion monitoring system research is not mature,and the application is very small in high-corrosion field such as oil field and chemical plants.This paper designed ultrasonic corrosion monitoring system to provide the basis of corrosion monitoring in high-corrosion field.This thesis worked is composed of six parts: First,this part reviews the background and significance of this research and the main corrosion monitoring technology,and clarifies the research status of ultrasonic corrosion monitoring and the waveguide technology.Second,the basic principle of ultrasonic corrosion monitoring and the design principle of a waveguide device are given,which provide the theoretical basis for system design,The system design scheme is determined by comparison.Thirdly,this part designs the front-end waveguide.Ascertains the design parameters of the waveguide,designs two sets of fixtures according to the practical application requirements,and carries out the steady state thermal analysis and transient wave analysis by using ANSYS software to verify a good performance of temperature buffer and the guided wave performance of the waveguide.Fourth,the hardware circuits of ultrasonic corrosion monitoring system are selected,designed and simulated.According to the overall scheme of the system,the power circuits,ultrasonic transmitting circuits,receiving circuits,time measuring circuits,control circuits and radio circuits design in turn to form a complete ultrasonic corrosion monitoring system.Fifth,this part analyzes the workflows of system software,builds the PC interface by LABVIEW platform.Sixth,this part finished the debugging of the circuit boards and achieved its circuit function.And then the different thickness of the steel plate is measured to determine the systematic error.At the same time,analyzing the causes of the systematic error to provide the basis of the instrument error compensation.